Revert "Update go-containerregistry to get https://github.com/google/go-containerregistry/pull/693"

This reverts commit f55c34ab92.

vendor/github.com/prometheus/client_golang/prometheus/build_info.go

@@ -1,29 +0,0 @@
-// Copyright 2019 The Prometheus Authors
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-// http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-// +build go1.12
-
-package prometheus
-
-import "runtime/debug"
-
-// readBuildInfo is a wrapper around debug.ReadBuildInfo for Go 1.12+.
-func readBuildInfo() (path, version, sum string) {
-	path, version, sum = "unknown", "unknown", "unknown"
-	if bi, ok := debug.ReadBuildInfo(); ok {
-		path = bi.Main.Path
-		version = bi.Main.Version
-		sum = bi.Main.Sum
-	}
-	return
-}

vendor/github.com/prometheus/client_golang/prometheus/build_info_pre_1.12.go

@@ -1,22 +0,0 @@
-// Copyright 2019 The Prometheus Authors
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-// http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-// +build !go1.12
-
-package prometheus
-
-// readBuildInfo is a wrapper around debug.ReadBuildInfo for Go versions before
-// 1.12. Remove this whole file once the minimum supported Go version is 1.12.
-func readBuildInfo() (path, version, sum string) {
-	return "unknown", "unknown", "unknown"
-}

vendor/github.com/prometheus/client_golang/prometheus/collector.go

@@ -29,72 +29,27 @@ type Collector interface {
 	// collected by this Collector to the provided channel and returns once
 	// the last descriptor has been sent. The sent descriptors fulfill the
 	// consistency and uniqueness requirements described in the Desc
-	// documentation.
-	//
-	// It is valid if one and the same Collector sends duplicate
-	// descriptors. Those duplicates are simply ignored. However, two
-	// different Collectors must not send duplicate descriptors.
-	//
-	// Sending no descriptor at all marks the Collector as “unchecked”,
-	// i.e. no checks will be performed at registration time, and the
-	// Collector may yield any Metric it sees fit in its Collect method.
-	//
-	// This method idempotently sends the same descriptors throughout the
-	// lifetime of the Collector. It may be called concurrently and
-	// therefore must be implemented in a concurrency safe way.
-	//
-	// If a Collector encounters an error while executing this method, it
-	// must send an invalid descriptor (created with NewInvalidDesc) to
-	// signal the error to the registry.
+	// documentation. (It is valid if one and the same Collector sends
+	// duplicate descriptors. Those duplicates are simply ignored. However,
+	// two different Collectors must not send duplicate descriptors.) This
+	// method idempotently sends the same descriptors throughout the
+	// lifetime of the Collector. If a Collector encounters an error while
+	// executing this method, it must send an invalid descriptor (created
+	// with NewInvalidDesc) to signal the error to the registry.
 	Describe(chan<- *Desc)
 	// Collect is called by the Prometheus registry when collecting
 	// metrics. The implementation sends each collected metric via the
 	// provided channel and returns once the last metric has been sent. The
-	// descriptor of each sent metric is one of those returned by Describe
-	// (unless the Collector is unchecked, see above). Returned metrics that
-	// share the same descriptor must differ in their variable label
-	// values.
-	//
-	// This method may be called concurrently and must therefore be
-	// implemented in a concurrency safe way. Blocking occurs at the expense
-	// of total performance of rendering all registered metrics. Ideally,
-	// Collector implementations support concurrent readers.
+	// descriptor of each sent metric is one of those returned by
+	// Describe. Returned metrics that share the same descriptor must differ
+	// in their variable label values. This method may be called
+	// concurrently and must therefore be implemented in a concurrency safe
+	// way. Blocking occurs at the expense of total performance of rendering
+	// all registered metrics. Ideally, Collector implementations support
+	// concurrent readers.
 	Collect(chan<- Metric)
 }
 
-// DescribeByCollect is a helper to implement the Describe method of a custom
-// Collector. It collects the metrics from the provided Collector and sends
-// their descriptors to the provided channel.
-//
-// If a Collector collects the same metrics throughout its lifetime, its
-// Describe method can simply be implemented as:
-//
-//   func (c customCollector) Describe(ch chan<- *Desc) {
-//   	DescribeByCollect(c, ch)
-//   }
-//
-// However, this will not work if the metrics collected change dynamically over
-// the lifetime of the Collector in a way that their combined set of descriptors
-// changes as well. The shortcut implementation will then violate the contract
-// of the Describe method. If a Collector sometimes collects no metrics at all
-// (for example vectors like CounterVec, GaugeVec, etc., which only collect
-// metrics after a metric with a fully specified label set has been accessed),
-// it might even get registered as an unchecked Collector (cf. the Register
-// method of the Registerer interface). Hence, only use this shortcut
-// implementation of Describe if you are certain to fulfill the contract.
-//
-// The Collector example demonstrates a use of DescribeByCollect.
-func DescribeByCollect(c Collector, descs chan<- *Desc) {
-	metrics := make(chan Metric)
-	go func() {
-		c.Collect(metrics)
-		close(metrics)
-	}()
-	for m := range metrics {
-		descs <- m.Desc()
-	}
-}
-
 // selfCollector implements Collector for a single Metric so that the Metric
 // collects itself. Add it as an anonymous field to a struct that implements
 // Metric, and call init with the Metric itself as an argument.

vendor/github.com/prometheus/client_golang/prometheus/counter.go

@@ -136,7 +136,7 @@ func NewCounterVec(opts CounterOpts, labelNames []string) *CounterVec {
 	return &CounterVec{
 		metricVec: newMetricVec(desc, func(lvs ...string) Metric {
 			if len(lvs) != len(desc.variableLabels) {
-				panic(makeInconsistentCardinalityError(desc.fqName, desc.variableLabels, lvs))
+				panic(errInconsistentCardinality)
 			}
 			result := &counter{desc: desc, labelPairs: makeLabelPairs(desc, lvs)}
 			result.init(result) // Init self-collection.

vendor/github.com/prometheus/client_golang/prometheus/desc.go

@@ -67,7 +67,7 @@ type Desc struct {
 
 // NewDesc allocates and initializes a new Desc. Errors are recorded in the Desc
 // and will be reported on registration time. variableLabels and constLabels can
-// be nil if no such labels should be set. fqName must not be empty.
+// be nil if no such labels should be set. fqName and help must not be empty.
 //
 // variableLabels only contain the label names. Their label values are variable
 // and therefore not part of the Desc. (They are managed within the Metric.)
@@ -80,6 +80,10 @@ func NewDesc(fqName, help string, variableLabels []string, constLabels Labels) *
 		help:           help,
 		variableLabels: variableLabels,
 	}
+	if help == "" {
+		d.err = errors.New("empty help string")
+		return d
+	}
 	if !model.IsValidMetricName(model.LabelValue(fqName)) {
 		d.err = fmt.Errorf("%q is not a valid metric name", fqName)
 		return d
@@ -93,7 +97,7 @@ func NewDesc(fqName, help string, variableLabels []string, constLabels Labels) *
 	// First add only the const label names and sort them...
 	for labelName := range constLabels {
 		if !checkLabelName(labelName) {
-			d.err = fmt.Errorf("%q is not a valid label name for metric %q", labelName, fqName)
+			d.err = fmt.Errorf("%q is not a valid label name", labelName)
 			return d
 		}
 		labelNames = append(labelNames, labelName)
@@ -115,7 +119,7 @@ func NewDesc(fqName, help string, variableLabels []string, constLabels Labels) *
 	// dimension with a different mix between preset and variable labels.
 	for _, labelName := range variableLabels {
 		if !checkLabelName(labelName) {
-			d.err = fmt.Errorf("%q is not a valid label name for metric %q", labelName, fqName)
+			d.err = fmt.Errorf("%q is not a valid label name", labelName)
 			return d
 		}
 		labelNames = append(labelNames, "$"+labelName)
@@ -152,7 +156,7 @@ func NewDesc(fqName, help string, variableLabels []string, constLabels Labels) *
 			Value: proto.String(v),
 		})
 	}
-	sort.Sort(labelPairSorter(d.constLabelPairs))
+	sort.Sort(LabelPairSorter(d.constLabelPairs))
 	return d
 }
 

vendor/github.com/prometheus/client_golang/prometheus/doc.go

@@ -11,12 +11,10 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-// Package prometheus is the core instrumentation package. It provides metrics
-// primitives to instrument code for monitoring. It also offers a registry for
-// metrics. Sub-packages allow to expose the registered metrics via HTTP
-// (package promhttp) or push them to a Pushgateway (package push). There is
-// also a sub-package promauto, which provides metrics constructors with
-// automatic registration.
+// Package prometheus provides metrics primitives to instrument code for
+// monitoring. It also offers a registry for metrics. Sub-packages allow to
+// expose the registered metrics via HTTP (package promhttp) or push them to a
+// Pushgateway (package push).
 //
 // All exported functions and methods are safe to be used concurrently unless
 // specified otherwise.
@@ -74,10 +72,7 @@
 // The number of exported identifiers in this package might appear a bit
 // overwhelming. However, in addition to the basic plumbing shown in the example
 // above, you only need to understand the different metric types and their
-// vector versions for basic usage. Furthermore, if you are not concerned with
-// fine-grained control of when and how to register metrics with the registry,
-// have a look at the promauto package, which will effectively allow you to
-// ignore registration altogether in simple cases.
+// vector versions for basic usage.
 //
 // Above, you have already touched the Counter and the Gauge. There are two more
 // advanced metric types: the Summary and Histogram. A more thorough description
@@ -121,17 +116,7 @@
 // NewConstSummary (and their respective Must… versions). That will happen in
 // the Collect method. The Describe method has to return separate Desc
 // instances, representative of the “throw-away” metrics to be created later.
-// NewDesc comes in handy to create those Desc instances. Alternatively, you
-// could return no Desc at all, which will mark the Collector “unchecked”.  No
-// checks are performed at registration time, but metric consistency will still
-// be ensured at scrape time, i.e. any inconsistencies will lead to scrape
-// errors. Thus, with unchecked Collectors, the responsibility to not collect
-// metrics that lead to inconsistencies in the total scrape result lies with the
-// implementer of the Collector. While this is not a desirable state, it is
-// sometimes necessary. The typical use case is a situation where the exact
-// metrics to be returned by a Collector cannot be predicted at registration
-// time, but the implementer has sufficient knowledge of the whole system to
-// guarantee metric consistency.
+// NewDesc comes in handy to create those Desc instances.
 //
 // The Collector example illustrates the use case. You can also look at the
 // source code of the processCollector (mirroring process metrics), the
@@ -183,6 +168,7 @@
 // method can then expose the gathered metrics in some way. Usually, the metrics
 // are served via HTTP on the /metrics endpoint. That's happening in the example
 // above. The tools to expose metrics via HTTP are in the promhttp sub-package.
+// (The top-level functions in the prometheus package are deprecated.)
 //
 // Pushing to the Pushgateway
 //

vendor/github.com/prometheus/client_golang/prometheus/fnv.go

@@ -1,16 +1,3 @@
-// Copyright 2018 The Prometheus Authors
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-// http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
 package prometheus
 
 // Inline and byte-free variant of hash/fnv's fnv64a.

vendor/github.com/prometheus/client_golang/prometheus/gauge.go

@@ -147,7 +147,7 @@ func NewGaugeVec(opts GaugeOpts, labelNames []string) *GaugeVec {
 	return &GaugeVec{
 		metricVec: newMetricVec(desc, func(lvs ...string) Metric {
 			if len(lvs) != len(desc.variableLabels) {
-				panic(makeInconsistentCardinalityError(desc.fqName, desc.variableLabels, lvs))
+				panic(errInconsistentCardinality)
 			}
 			result := &gauge{desc: desc, labelPairs: makeLabelPairs(desc, lvs)}
 			result.init(result) // Init self-collection.

vendor/github.com/prometheus/client_golang/prometheus/go_collector.go

@@ -1,22 +1,9 @@
-// Copyright 2018 The Prometheus Authors
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-// http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
 package prometheus
 
 import (
+	"fmt"
 	"runtime"
 	"runtime/debug"
-	"sync"
 	"time"
 )
 
@@ -26,41 +13,12 @@ type goCollector struct {
 	gcDesc         *Desc
 	goInfoDesc     *Desc
 
-	// ms... are memstats related.
-	msLast          *runtime.MemStats // Previously collected memstats.
-	msLastTimestamp time.Time
-	msMtx           sync.Mutex // Protects msLast and msLastTimestamp.
-	msMetrics       memStatsMetrics
-	msRead          func(*runtime.MemStats) // For mocking in tests.
-	msMaxWait       time.Duration           // Wait time for fresh memstats.
-	msMaxAge        time.Duration           // Maximum allowed age of old memstats.
+	// metrics to describe and collect
+	metrics memStatsMetrics
 }
 
-// NewGoCollector returns a collector that exports metrics about the current Go
-// process. This includes memory stats. To collect those, runtime.ReadMemStats
-// is called. This requires to “stop the world”, which usually only happens for
-// garbage collection (GC). Take the following implications into account when
-// deciding whether to use the Go collector:
-//
-// 1. The performance impact of stopping the world is the more relevant the more
-// frequently metrics are collected. However, with Go1.9 or later the
-// stop-the-world time per metrics collection is very short (~25µs) so that the
-// performance impact will only matter in rare cases. However, with older Go
-// versions, the stop-the-world duration depends on the heap size and can be
-// quite significant (~1.7 ms/GiB as per
-// https://go-review.googlesource.com/c/go/+/34937).
-//
-// 2. During an ongoing GC, nothing else can stop the world. Therefore, if the
-// metrics collection happens to coincide with GC, it will only complete after
-// GC has finished. Usually, GC is fast enough to not cause problems. However,
-// with a very large heap, GC might take multiple seconds, which is enough to
-// cause scrape timeouts in common setups. To avoid this problem, the Go
-// collector will use the memstats from a previous collection if
-// runtime.ReadMemStats takes more than 1s. However, if there are no previously
-// collected memstats, or their collection is more than 5m ago, the collection
-// will block until runtime.ReadMemStats succeeds. (The problem might be solved
-// in Go1.13, see https://github.com/golang/go/issues/19812 for the related Go
-// issue.)
+// NewGoCollector returns a collector which exports metrics about the current
+// go process.
 func NewGoCollector() Collector {
 	return &goCollector{
 		goroutinesDesc: NewDesc(
@@ -79,11 +37,7 @@ func NewGoCollector() Collector {
 			"go_info",
 			"Information about the Go environment.",
 			nil, Labels{"version": runtime.Version()}),
-		msLast:    &runtime.MemStats{},
-		msRead:    runtime.ReadMemStats,
-		msMaxWait: time.Second,
-		msMaxAge:  5 * time.Minute,
-		msMetrics: memStatsMetrics{
+		metrics: memStatsMetrics{
 			{
 				desc: NewDesc(
 					memstatNamespace("alloc_bytes"),
@@ -282,7 +236,7 @@ func NewGoCollector() Collector {
 }
 
 func memstatNamespace(s string) string {
-	return "go_memstats_" + s
+	return fmt.Sprintf("go_memstats_%s", s)
 }
 
 // Describe returns all descriptions of the collector.
@@ -291,27 +245,13 @@ func (c *goCollector) Describe(ch chan<- *Desc) {
 	ch <- c.threadsDesc
 	ch <- c.gcDesc
 	ch <- c.goInfoDesc
-	for _, i := range c.msMetrics {
+	for _, i := range c.metrics {
 		ch <- i.desc
 	}
 }
 
 // Collect returns the current state of all metrics of the collector.
 func (c *goCollector) Collect(ch chan<- Metric) {
-	var (
-		ms   = &runtime.MemStats{}
-		done = make(chan struct{})
-	)
-	// Start reading memstats first as it might take a while.
-	go func() {
-		c.msRead(ms)
-		c.msMtx.Lock()
-		c.msLast = ms
-		c.msLastTimestamp = time.Now()
-		c.msMtx.Unlock()
-		close(done)
-	}()
-
 	ch <- MustNewConstMetric(c.goroutinesDesc, GaugeValue, float64(runtime.NumGoroutine()))
 	n, _ := runtime.ThreadCreateProfile(nil)
 	ch <- MustNewConstMetric(c.threadsDesc, GaugeValue, float64(n))
@@ -325,35 +265,13 @@ func (c *goCollector) Collect(ch chan<- Metric) {
 		quantiles[float64(idx+1)/float64(len(stats.PauseQuantiles)-1)] = pq.Seconds()
 	}
 	quantiles[0.0] = stats.PauseQuantiles[0].Seconds()
-	ch <- MustNewConstSummary(c.gcDesc, uint64(stats.NumGC), stats.PauseTotal.Seconds(), quantiles)
+	ch <- MustNewConstSummary(c.gcDesc, uint64(stats.NumGC), float64(stats.PauseTotal.Seconds()), quantiles)
 
 	ch <- MustNewConstMetric(c.goInfoDesc, GaugeValue, 1)
 
-	timer := time.NewTimer(c.msMaxWait)
-	select {
-	case <-done: // Our own ReadMemStats succeeded in time. Use it.
-		timer.Stop() // Important for high collection frequencies to not pile up timers.
-		c.msCollect(ch, ms)
-		return
-	case <-timer.C: // Time out, use last memstats if possible. Continue below.
-	}
-	c.msMtx.Lock()
-	if time.Since(c.msLastTimestamp) < c.msMaxAge {
-		// Last memstats are recent enough. Collect from them under the lock.
-		c.msCollect(ch, c.msLast)
-		c.msMtx.Unlock()
-		return
-	}
-	// If we are here, the last memstats are too old or don't exist. We have
-	// to wait until our own ReadMemStats finally completes. For that to
-	// happen, we have to release the lock.
-	c.msMtx.Unlock()
-	<-done
-	c.msCollect(ch, ms)
-}
-
-func (c *goCollector) msCollect(ch chan<- Metric, ms *runtime.MemStats) {
-	for _, i := range c.msMetrics {
+	ms := &runtime.MemStats{}
+	runtime.ReadMemStats(ms)
+	for _, i := range c.metrics {
 		ch <- MustNewConstMetric(i.desc, i.valType, i.eval(ms))
 	}
 }
@@ -364,33 +282,3 @@ type memStatsMetrics []struct {
 	eval    func(*runtime.MemStats) float64
 	valType ValueType
 }
-
-// NewBuildInfoCollector returns a collector collecting a single metric
-// "go_build_info" with the constant value 1 and three labels "path", "version",
-// and "checksum". Their label values contain the main module path, version, and
-// checksum, respectively. The labels will only have meaningful values if the
-// binary is built with Go module support and from source code retrieved from
-// the source repository (rather than the local file system). This is usually
-// accomplished by building from outside of GOPATH, specifying the full address
-// of the main package, e.g. "GO111MODULE=on go run
-// github.com/prometheus/client_golang/examples/random". If built without Go
-// module support, all label values will be "unknown". If built with Go module
-// support but using the source code from the local file system, the "path" will
-// be set appropriately, but "checksum" will be empty and "version" will be
-// "(devel)".
-//
-// This collector uses only the build information for the main module. See
-// https://github.com/povilasv/prommod for an example of a collector for the
-// module dependencies.
-func NewBuildInfoCollector() Collector {
-	path, version, sum := readBuildInfo()
-	c := &selfCollector{MustNewConstMetric(
-		NewDesc(
-			"go_build_info",
-			"Build information about the main Go module.",
-			nil, Labels{"path": path, "version": version, "checksum": sum},
-		),
-		GaugeValue, 1)}
-	c.init(c.self)
-	return c
-}

vendor/github.com/prometheus/client_golang/prometheus/histogram.go

@@ -16,9 +16,7 @@ package prometheus
 import (
 	"fmt"
 	"math"
-	"runtime"
 	"sort"
-	"sync"
 	"sync/atomic"
 
 	"github.com/golang/protobuf/proto"
@@ -110,9 +108,8 @@ func ExponentialBuckets(start, factor float64, count int) []float64 {
 }
 
 // HistogramOpts bundles the options for creating a Histogram metric. It is
-// mandatory to set Name to a non-empty string. All other fields are optional
-// and can safely be left at their zero value, although it is strongly
-// encouraged to set a Help string.
+// mandatory to set Name and Help to a non-empty string. All other fields are
+// optional and can safely be left at their zero value.
 type HistogramOpts struct {
 	// Namespace, Subsystem, and Name are components of the fully-qualified
 	// name of the Histogram (created by joining these components with
@@ -123,7 +120,7 @@ type HistogramOpts struct {
 	Subsystem string
 	Name      string
 
-	// Help provides information about this Histogram.
+	// Help provides information about this Histogram. Mandatory!
 	//
 	// Metrics with the same fully-qualified name must have the same Help
 	// string.
@@ -165,7 +162,7 @@ func NewHistogram(opts HistogramOpts) Histogram {
 
 func newHistogram(desc *Desc, opts HistogramOpts, labelValues ...string) Histogram {
 	if len(desc.variableLabels) != len(labelValues) {
-		panic(makeInconsistentCardinalityError(desc.fqName, desc.variableLabels, labelValues))
+		panic(errInconsistentCardinality)
 	}
 
 	for _, n := range desc.variableLabels {
@@ -187,7 +184,6 @@ func newHistogram(desc *Desc, opts HistogramOpts, labelValues ...string) Histogr
 		desc:        desc,
 		upperBounds: opts.Buckets,
 		labelPairs:  makeLabelPairs(desc, labelValues),
-		counts:      [2]*histogramCounts{&histogramCounts{}, &histogramCounts{}},
 	}
 	for i, upperBound := range h.upperBounds {
 		if i < len(h.upperBounds)-1 {
@@ -204,56 +200,30 @@ func newHistogram(desc *Desc, opts HistogramOpts, labelValues ...string) Histogr
 			}
 		}
 	}
-	// Finally we know the final length of h.upperBounds and can make buckets
-	// for both counts:
-	h.counts[0].buckets = make([]uint64, len(h.upperBounds))
-	h.counts[1].buckets = make([]uint64, len(h.upperBounds))
+	// Finally we know the final length of h.upperBounds and can make counts.
+	h.counts = make([]uint64, len(h.upperBounds))
 
 	h.init(h) // Init self-collection.
 	return h
 }
 
-type histogramCounts struct {
+type histogram struct {
 	// sumBits contains the bits of the float64 representing the sum of all
 	// observations. sumBits and count have to go first in the struct to
 	// guarantee alignment for atomic operations.
 	// http://golang.org/pkg/sync/atomic/#pkg-note-BUG
 	sumBits uint64
 	count   uint64
-	buckets []uint64
-}
-
-type histogram struct {
-	// countAndHotIdx enables lock-free writes with use of atomic updates.
-	// The most significant bit is the hot index [0 or 1] of the count field
-	// below. Observe calls update the hot one. All remaining bits count the
-	// number of Observe calls. Observe starts by incrementing this counter,
-	// and finish by incrementing the count field in the respective
-	// histogramCounts, as a marker for completion.
-	//
-	// Calls of the Write method (which are non-mutating reads from the
-	// perspective of the histogram) swap the hot–cold under the writeMtx
-	// lock. A cooldown is awaited (while locked) by comparing the number of
-	// observations with the initiation count. Once they match, then the
-	// last observation on the now cool one has completed. All cool fields must
-	// be merged into the new hot before releasing writeMtx.
-	//
-	// Fields with atomic access first! See alignment constraint:
-	// http://golang.org/pkg/sync/atomic/#pkg-note-BUG
-	countAndHotIdx uint64
 
 	selfCollector
-	desc     *Desc
-	writeMtx sync.Mutex // Only used in the Write method.
+	// Note that there is no mutex required.
 
-	// Two counts, one is "hot" for lock-free observations, the other is
-	// "cold" for writing out a dto.Metric. It has to be an array of
-	// pointers to guarantee 64bit alignment of the histogramCounts, see
-	// http://golang.org/pkg/sync/atomic/#pkg-note-BUG.
-	counts [2]*histogramCounts
+	desc *Desc
 
 	upperBounds []float64
-	labelPairs  []*dto.LabelPair
+	counts      []uint64
+
+	labelPairs []*dto.LabelPair
 }
 
 func (h *histogram) Desc() *Desc {
@@ -271,84 +241,36 @@ func (h *histogram) Observe(v float64) {
 	// 100 buckets: 78.1 ns/op linear - binary 54.9 ns/op
 	// 300 buckets: 154 ns/op linear - binary 61.6 ns/op
 	i := sort.SearchFloat64s(h.upperBounds, v)
-
-	// We increment h.countAndHotIdx so that the counter in the lower
-	// 63 bits gets incremented. At the same time, we get the new value
-	// back, which we can use to find the currently-hot counts.
-	n := atomic.AddUint64(&h.countAndHotIdx, 1)
-	hotCounts := h.counts[n>>63]
-
-	if i < len(h.upperBounds) {
-		atomic.AddUint64(&hotCounts.buckets[i], 1)
+	if i < len(h.counts) {
+		atomic.AddUint64(&h.counts[i], 1)
 	}
+	atomic.AddUint64(&h.count, 1)
 	for {
-		oldBits := atomic.LoadUint64(&hotCounts.sumBits)
+		oldBits := atomic.LoadUint64(&h.sumBits)
 		newBits := math.Float64bits(math.Float64frombits(oldBits) + v)
-		if atomic.CompareAndSwapUint64(&hotCounts.sumBits, oldBits, newBits) {
+		if atomic.CompareAndSwapUint64(&h.sumBits, oldBits, newBits) {
 			break
 		}
 	}
-	// Increment count last as we take it as a signal that the observation
-	// is complete.
-	atomic.AddUint64(&hotCounts.count, 1)
 }
 
 func (h *histogram) Write(out *dto.Metric) error {
-	// For simplicity, we protect this whole method by a mutex. It is not in
-	// the hot path, i.e. Observe is called much more often than Write. The
-	// complication of making Write lock-free isn't worth it, if possible at
-	// all.
-	h.writeMtx.Lock()
-	defer h.writeMtx.Unlock()
+	his := &dto.Histogram{}
+	buckets := make([]*dto.Bucket, len(h.upperBounds))
 
-	// Adding 1<<63 switches the hot index (from 0 to 1 or from 1 to 0)
-	// without touching the count bits. See the struct comments for a full
-	// description of the algorithm.
-	n := atomic.AddUint64(&h.countAndHotIdx, 1<<63)
-	// count is contained unchanged in the lower 63 bits.
-	count := n & ((1 << 63) - 1)
-	// The most significant bit tells us which counts is hot. The complement
-	// is thus the cold one.
-	hotCounts := h.counts[n>>63]
-	coldCounts := h.counts[(^n)>>63]
-
-	// Await cooldown.
-	for count != atomic.LoadUint64(&coldCounts.count) {
-		runtime.Gosched() // Let observations get work done.
-	}
-
-	his := &dto.Histogram{
-		Bucket:      make([]*dto.Bucket, len(h.upperBounds)),
-		SampleCount: proto.Uint64(count),
-		SampleSum:   proto.Float64(math.Float64frombits(atomic.LoadUint64(&coldCounts.sumBits))),
-	}
-	var cumCount uint64
+	his.SampleSum = proto.Float64(math.Float64frombits(atomic.LoadUint64(&h.sumBits)))
+	his.SampleCount = proto.Uint64(atomic.LoadUint64(&h.count))
+	var count uint64
 	for i, upperBound := range h.upperBounds {
-		cumCount += atomic.LoadUint64(&coldCounts.buckets[i])
-		his.Bucket[i] = &dto.Bucket{
-			CumulativeCount: proto.Uint64(cumCount),
+		count += atomic.LoadUint64(&h.counts[i])
+		buckets[i] = &dto.Bucket{
+			CumulativeCount: proto.Uint64(count),
 			UpperBound:      proto.Float64(upperBound),
 		}
 	}
-
+	his.Bucket = buckets
 	out.Histogram = his
 	out.Label = h.labelPairs
-
-	// Finally add all the cold counts to the new hot counts and reset the cold counts.
-	atomic.AddUint64(&hotCounts.count, count)
-	atomic.StoreUint64(&coldCounts.count, 0)
-	for {
-		oldBits := atomic.LoadUint64(&hotCounts.sumBits)
-		newBits := math.Float64bits(math.Float64frombits(oldBits) + his.GetSampleSum())
-		if atomic.CompareAndSwapUint64(&hotCounts.sumBits, oldBits, newBits) {
-			atomic.StoreUint64(&coldCounts.sumBits, 0)
-			break
-		}
-	}
-	for i := range h.upperBounds {
-		atomic.AddUint64(&hotCounts.buckets[i], atomic.LoadUint64(&coldCounts.buckets[i]))
-		atomic.StoreUint64(&coldCounts.buckets[i], 0)
-	}
 	return nil
 }
 
@@ -532,7 +454,7 @@ func (h *constHistogram) Write(out *dto.Metric) error {
 // bucket.
 //
 // NewConstHistogram returns an error if the length of labelValues is not
-// consistent with the variable labels in Desc or if Desc is invalid.
+// consistent with the variable labels in Desc.
 func NewConstHistogram(
 	desc *Desc,
 	count uint64,
@@ -540,9 +462,6 @@ func NewConstHistogram(
 	buckets map[float64]uint64,
 	labelValues ...string,
 ) (Metric, error) {
-	if desc.err != nil {
-		return nil, desc.err
-	}
 	if err := validateLabelValues(labelValues, len(desc.variableLabels)); err != nil {
 		return nil, err
 	}

vendor/github.com/prometheus/client_golang/prometheus/http.go

@@ -0,0 +1,523 @@
+// Copyright 2014 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package prometheus
+
+import (
+	"bufio"
+	"bytes"
+	"compress/gzip"
+	"fmt"
+	"io"
+	"net"
+	"net/http"
+	"strconv"
+	"strings"
+	"sync"
+	"time"
+
+	"github.com/prometheus/common/expfmt"
+)
+
+// TODO(beorn7): Remove this whole file. It is a partial mirror of
+// promhttp/http.go (to avoid circular import chains) where everything HTTP
+// related should live. The functions here are just for avoiding
+// breakage. Everything is deprecated.
+
+const (
+	contentTypeHeader     = "Content-Type"
+	contentLengthHeader   = "Content-Length"
+	contentEncodingHeader = "Content-Encoding"
+	acceptEncodingHeader  = "Accept-Encoding"
+)
+
+var bufPool sync.Pool
+
+func getBuf() *bytes.Buffer {
+	buf := bufPool.Get()
+	if buf == nil {
+		return &bytes.Buffer{}
+	}
+	return buf.(*bytes.Buffer)
+}
+
+func giveBuf(buf *bytes.Buffer) {
+	buf.Reset()
+	bufPool.Put(buf)
+}
+
+// Handler returns an HTTP handler for the DefaultGatherer. It is
+// already instrumented with InstrumentHandler (using "prometheus" as handler
+// name).
+//
+// Deprecated: Please note the issues described in the doc comment of
+// InstrumentHandler. You might want to consider using
+// promhttp.InstrumentedHandler instead.
+func Handler() http.Handler {
+	return InstrumentHandler("prometheus", UninstrumentedHandler())
+}
+
+// UninstrumentedHandler returns an HTTP handler for the DefaultGatherer.
+//
+// Deprecated: Use promhttp.Handler instead. See there for further documentation.
+func UninstrumentedHandler() http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, req *http.Request) {
+		mfs, err := DefaultGatherer.Gather()
+		if err != nil {
+			http.Error(w, "An error has occurred during metrics collection:\n\n"+err.Error(), http.StatusInternalServerError)
+			return
+		}
+
+		contentType := expfmt.Negotiate(req.Header)
+		buf := getBuf()
+		defer giveBuf(buf)
+		writer, encoding := decorateWriter(req, buf)
+		enc := expfmt.NewEncoder(writer, contentType)
+		var lastErr error
+		for _, mf := range mfs {
+			if err := enc.Encode(mf); err != nil {
+				lastErr = err
+				http.Error(w, "An error has occurred during metrics encoding:\n\n"+err.Error(), http.StatusInternalServerError)
+				return
+			}
+		}
+		if closer, ok := writer.(io.Closer); ok {
+			closer.Close()
+		}
+		if lastErr != nil && buf.Len() == 0 {
+			http.Error(w, "No metrics encoded, last error:\n\n"+lastErr.Error(), http.StatusInternalServerError)
+			return
+		}
+		header := w.Header()
+		header.Set(contentTypeHeader, string(contentType))
+		header.Set(contentLengthHeader, fmt.Sprint(buf.Len()))
+		if encoding != "" {
+			header.Set(contentEncodingHeader, encoding)
+		}
+		w.Write(buf.Bytes())
+	})
+}
+
+// decorateWriter wraps a writer to handle gzip compression if requested.  It
+// returns the decorated writer and the appropriate "Content-Encoding" header
+// (which is empty if no compression is enabled).
+func decorateWriter(request *http.Request, writer io.Writer) (io.Writer, string) {
+	header := request.Header.Get(acceptEncodingHeader)
+	parts := strings.Split(header, ",")
+	for _, part := range parts {
+		part := strings.TrimSpace(part)
+		if part == "gzip" || strings.HasPrefix(part, "gzip;") {
+			return gzip.NewWriter(writer), "gzip"
+		}
+	}
+	return writer, ""
+}
+
+var instLabels = []string{"method", "code"}
+
+type nower interface {
+	Now() time.Time
+}
+
+type nowFunc func() time.Time
+
+func (n nowFunc) Now() time.Time {
+	return n()
+}
+
+var now nower = nowFunc(func() time.Time {
+	return time.Now()
+})
+
+func nowSeries(t ...time.Time) nower {
+	return nowFunc(func() time.Time {
+		defer func() {
+			t = t[1:]
+		}()
+
+		return t[0]
+	})
+}
+
+// InstrumentHandler wraps the given HTTP handler for instrumentation. It
+// registers four metric collectors (if not already done) and reports HTTP
+// metrics to the (newly or already) registered collectors: http_requests_total
+// (CounterVec), http_request_duration_microseconds (Summary),
+// http_request_size_bytes (Summary), http_response_size_bytes (Summary). Each
+// has a constant label named "handler" with the provided handlerName as
+// value. http_requests_total is a metric vector partitioned by HTTP method
+// (label name "method") and HTTP status code (label name "code").
+//
+// Deprecated: InstrumentHandler has several issues. Use the tooling provided in
+// package promhttp instead. The issues are the following:
+//
+// - It uses Summaries rather than Histograms. Summaries are not useful if
+// aggregation across multiple instances is required.
+//
+// - It uses microseconds as unit, which is deprecated and should be replaced by
+// seconds.
+//
+// - The size of the request is calculated in a separate goroutine. Since this
+// calculator requires access to the request header, it creates a race with
+// any writes to the header performed during request handling.
+// httputil.ReverseProxy is a prominent example for a handler
+// performing such writes.
+//
+// - It has additional issues with HTTP/2, cf.
+// https://github.com/prometheus/client_golang/issues/272.
+func InstrumentHandler(handlerName string, handler http.Handler) http.HandlerFunc {
+	return InstrumentHandlerFunc(handlerName, handler.ServeHTTP)
+}
+
+// InstrumentHandlerFunc wraps the given function for instrumentation. It
+// otherwise works in the same way as InstrumentHandler (and shares the same
+// issues).
+//
+// Deprecated: InstrumentHandlerFunc is deprecated for the same reasons as
+// InstrumentHandler is. Use the tooling provided in package promhttp instead.
+func InstrumentHandlerFunc(handlerName string, handlerFunc func(http.ResponseWriter, *http.Request)) http.HandlerFunc {
+	return InstrumentHandlerFuncWithOpts(
+		SummaryOpts{
+			Subsystem:   "http",
+			ConstLabels: Labels{"handler": handlerName},
+			Objectives:  map[float64]float64{0.5: 0.05, 0.9: 0.01, 0.99: 0.001},
+		},
+		handlerFunc,
+	)
+}
+
+// InstrumentHandlerWithOpts works like InstrumentHandler (and shares the same
+// issues) but provides more flexibility (at the cost of a more complex call
+// syntax). As InstrumentHandler, this function registers four metric
+// collectors, but it uses the provided SummaryOpts to create them. However, the
+// fields "Name" and "Help" in the SummaryOpts are ignored. "Name" is replaced
+// by "requests_total", "request_duration_microseconds", "request_size_bytes",
+// and "response_size_bytes", respectively. "Help" is replaced by an appropriate
+// help string. The names of the variable labels of the http_requests_total
+// CounterVec are "method" (get, post, etc.), and "code" (HTTP status code).
+//
+// If InstrumentHandlerWithOpts is called as follows, it mimics exactly the
+// behavior of InstrumentHandler:
+//
+//     prometheus.InstrumentHandlerWithOpts(
+//         prometheus.SummaryOpts{
+//              Subsystem:   "http",
+//              ConstLabels: prometheus.Labels{"handler": handlerName},
+//         },
+//         handler,
+//     )
+//
+// Technical detail: "requests_total" is a CounterVec, not a SummaryVec, so it
+// cannot use SummaryOpts. Instead, a CounterOpts struct is created internally,
+// and all its fields are set to the equally named fields in the provided
+// SummaryOpts.
+//
+// Deprecated: InstrumentHandlerWithOpts is deprecated for the same reasons as
+// InstrumentHandler is. Use the tooling provided in package promhttp instead.
+func InstrumentHandlerWithOpts(opts SummaryOpts, handler http.Handler) http.HandlerFunc {
+	return InstrumentHandlerFuncWithOpts(opts, handler.ServeHTTP)
+}
+
+// InstrumentHandlerFuncWithOpts works like InstrumentHandlerFunc (and shares
+// the same issues) but provides more flexibility (at the cost of a more complex
+// call syntax). See InstrumentHandlerWithOpts for details how the provided
+// SummaryOpts are used.
+//
+// Deprecated: InstrumentHandlerFuncWithOpts is deprecated for the same reasons
+// as InstrumentHandler is. Use the tooling provided in package promhttp instead.
+func InstrumentHandlerFuncWithOpts(opts SummaryOpts, handlerFunc func(http.ResponseWriter, *http.Request)) http.HandlerFunc {
+	reqCnt := NewCounterVec(
+		CounterOpts{
+			Namespace:   opts.Namespace,
+			Subsystem:   opts.Subsystem,
+			Name:        "requests_total",
+			Help:        "Total number of HTTP requests made.",
+			ConstLabels: opts.ConstLabels,
+		},
+		instLabels,
+	)
+	if err := Register(reqCnt); err != nil {
+		if are, ok := err.(AlreadyRegisteredError); ok {
+			reqCnt = are.ExistingCollector.(*CounterVec)
+		} else {
+			panic(err)
+		}
+	}
+
+	opts.Name = "request_duration_microseconds"
+	opts.Help = "The HTTP request latencies in microseconds."
+	reqDur := NewSummary(opts)
+	if err := Register(reqDur); err != nil {
+		if are, ok := err.(AlreadyRegisteredError); ok {
+			reqDur = are.ExistingCollector.(Summary)
+		} else {
+			panic(err)
+		}
+	}
+
+	opts.Name = "request_size_bytes"
+	opts.Help = "The HTTP request sizes in bytes."
+	reqSz := NewSummary(opts)
+	if err := Register(reqSz); err != nil {
+		if are, ok := err.(AlreadyRegisteredError); ok {
+			reqSz = are.ExistingCollector.(Summary)
+		} else {
+			panic(err)
+		}
+	}
+
+	opts.Name = "response_size_bytes"
+	opts.Help = "The HTTP response sizes in bytes."
+	resSz := NewSummary(opts)
+	if err := Register(resSz); err != nil {
+		if are, ok := err.(AlreadyRegisteredError); ok {
+			resSz = are.ExistingCollector.(Summary)
+		} else {
+			panic(err)
+		}
+	}
+
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		now := time.Now()
+
+		delegate := &responseWriterDelegator{ResponseWriter: w}
+		out := computeApproximateRequestSize(r)
+
+		_, cn := w.(http.CloseNotifier)
+		_, fl := w.(http.Flusher)
+		_, hj := w.(http.Hijacker)
+		_, rf := w.(io.ReaderFrom)
+		var rw http.ResponseWriter
+		if cn && fl && hj && rf {
+			rw = &fancyResponseWriterDelegator{delegate}
+		} else {
+			rw = delegate
+		}
+		handlerFunc(rw, r)
+
+		elapsed := float64(time.Since(now)) / float64(time.Microsecond)
+
+		method := sanitizeMethod(r.Method)
+		code := sanitizeCode(delegate.status)
+		reqCnt.WithLabelValues(method, code).Inc()
+		reqDur.Observe(elapsed)
+		resSz.Observe(float64(delegate.written))
+		reqSz.Observe(float64(<-out))
+	})
+}
+
+func computeApproximateRequestSize(r *http.Request) <-chan int {
+	// Get URL length in current go routine for avoiding a race condition.
+	// HandlerFunc that runs in parallel may modify the URL.
+	s := 0
+	if r.URL != nil {
+		s += len(r.URL.String())
+	}
+
+	out := make(chan int, 1)
+
+	go func() {
+		s += len(r.Method)
+		s += len(r.Proto)
+		for name, values := range r.Header {
+			s += len(name)
+			for _, value := range values {
+				s += len(value)
+			}
+		}
+		s += len(r.Host)
+
+		// N.B. r.Form and r.MultipartForm are assumed to be included in r.URL.
+
+		if r.ContentLength != -1 {
+			s += int(r.ContentLength)
+		}
+		out <- s
+		close(out)
+	}()
+
+	return out
+}
+
+type responseWriterDelegator struct {
+	http.ResponseWriter
+
+	handler, method string
+	status          int
+	written         int64
+	wroteHeader     bool
+}
+
+func (r *responseWriterDelegator) WriteHeader(code int) {
+	r.status = code
+	r.wroteHeader = true
+	r.ResponseWriter.WriteHeader(code)
+}
+
+func (r *responseWriterDelegator) Write(b []byte) (int, error) {
+	if !r.wroteHeader {
+		r.WriteHeader(http.StatusOK)
+	}
+	n, err := r.ResponseWriter.Write(b)
+	r.written += int64(n)
+	return n, err
+}
+
+type fancyResponseWriterDelegator struct {
+	*responseWriterDelegator
+}
+
+func (f *fancyResponseWriterDelegator) CloseNotify() <-chan bool {
+	return f.ResponseWriter.(http.CloseNotifier).CloseNotify()
+}
+
+func (f *fancyResponseWriterDelegator) Flush() {
+	f.ResponseWriter.(http.Flusher).Flush()
+}
+
+func (f *fancyResponseWriterDelegator) Hijack() (net.Conn, *bufio.ReadWriter, error) {
+	return f.ResponseWriter.(http.Hijacker).Hijack()
+}
+
+func (f *fancyResponseWriterDelegator) ReadFrom(r io.Reader) (int64, error) {
+	if !f.wroteHeader {
+		f.WriteHeader(http.StatusOK)
+	}
+	n, err := f.ResponseWriter.(io.ReaderFrom).ReadFrom(r)
+	f.written += n
+	return n, err
+}
+
+func sanitizeMethod(m string) string {
+	switch m {
+	case "GET", "get":
+		return "get"
+	case "PUT", "put":
+		return "put"
+	case "HEAD", "head":
+		return "head"
+	case "POST", "post":
+		return "post"
+	case "DELETE", "delete":
+		return "delete"
+	case "CONNECT", "connect":
+		return "connect"
+	case "OPTIONS", "options":
+		return "options"
+	case "NOTIFY", "notify":
+		return "notify"
+	default:
+		return strings.ToLower(m)
+	}
+}
+
+func sanitizeCode(s int) string {
+	switch s {
+	case 100:
+		return "100"
+	case 101:
+		return "101"
+
+	case 200:
+		return "200"
+	case 201:
+		return "201"
+	case 202:
+		return "202"
+	case 203:
+		return "203"
+	case 204:
+		return "204"
+	case 205:
+		return "205"
+	case 206:
+		return "206"
+
+	case 300:
+		return "300"
+	case 301:
+		return "301"
+	case 302:
+		return "302"
+	case 304:
+		return "304"
+	case 305:
+		return "305"
+	case 307:
+		return "307"
+
+	case 400:
+		return "400"
+	case 401:
+		return "401"
+	case 402:
+		return "402"
+	case 403:
+		return "403"
+	case 404:
+		return "404"
+	case 405:
+		return "405"
+	case 406:
+		return "406"
+	case 407:
+		return "407"
+	case 408:
+		return "408"
+	case 409:
+		return "409"
+	case 410:
+		return "410"
+	case 411:
+		return "411"
+	case 412:
+		return "412"
+	case 413:
+		return "413"
+	case 414:
+		return "414"
+	case 415:
+		return "415"
+	case 416:
+		return "416"
+	case 417:
+		return "417"
+	case 418:
+		return "418"
+
+	case 500:
+		return "500"
+	case 501:
+		return "501"
+	case 502:
+		return "502"
+	case 503:
+		return "503"
+	case 504:
+		return "504"
+	case 505:
+		return "505"
+
+	case 428:
+		return "428"
+	case 429:
+		return "429"
+	case 431:
+		return "431"
+	case 511:
+		return "511"
+
+	default:
+		return strconv.Itoa(s)
+	}
+}

vendor/github.com/prometheus/client_golang/prometheus/internal/metric.go

@@ -1,85 +0,0 @@
-// Copyright 2018 The Prometheus Authors
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-// http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-package internal
-
-import (
-	"sort"
-
-	dto "github.com/prometheus/client_model/go"
-)
-
-// metricSorter is a sortable slice of *dto.Metric.
-type metricSorter []*dto.Metric
-
-func (s metricSorter) Len() int {
-	return len(s)
-}
-
-func (s metricSorter) Swap(i, j int) {
-	s[i], s[j] = s[j], s[i]
-}
-
-func (s metricSorter) Less(i, j int) bool {
-	if len(s[i].Label) != len(s[j].Label) {
-		// This should not happen. The metrics are
-		// inconsistent. However, we have to deal with the fact, as
-		// people might use custom collectors or metric family injection
-		// to create inconsistent metrics. So let's simply compare the
-		// number of labels in this case. That will still yield
-		// reproducible sorting.
-		return len(s[i].Label) < len(s[j].Label)
-	}
-	for n, lp := range s[i].Label {
-		vi := lp.GetValue()
-		vj := s[j].Label[n].GetValue()
-		if vi != vj {
-			return vi < vj
-		}
-	}
-
-	// We should never arrive here. Multiple metrics with the same
-	// label set in the same scrape will lead to undefined ingestion
-	// behavior. However, as above, we have to provide stable sorting
-	// here, even for inconsistent metrics. So sort equal metrics
-	// by their timestamp, with missing timestamps (implying "now")
-	// coming last.
-	if s[i].TimestampMs == nil {
-		return false
-	}
-	if s[j].TimestampMs == nil {
-		return true
-	}
-	return s[i].GetTimestampMs() < s[j].GetTimestampMs()
-}
-
-// NormalizeMetricFamilies returns a MetricFamily slice with empty
-// MetricFamilies pruned and the remaining MetricFamilies sorted by name within
-// the slice, with the contained Metrics sorted within each MetricFamily.
-func NormalizeMetricFamilies(metricFamiliesByName map[string]*dto.MetricFamily) []*dto.MetricFamily {
-	for _, mf := range metricFamiliesByName {
-		sort.Sort(metricSorter(mf.Metric))
-	}
-	names := make([]string, 0, len(metricFamiliesByName))
-	for name, mf := range metricFamiliesByName {
-		if len(mf.Metric) > 0 {
-			names = append(names, name)
-		}
-	}
-	sort.Strings(names)
-	result := make([]*dto.MetricFamily, 0, len(names))
-	for _, name := range names {
-		result = append(result, metricFamiliesByName[name])
-	}
-	return result
-}

vendor/github.com/prometheus/client_golang/prometheus/labels.go

@@ -1,16 +1,3 @@
-// Copyright 2018 The Prometheus Authors
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-// http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
 package prometheus
 
 import (
@@ -37,22 +24,9 @@ const reservedLabelPrefix = "__"
 
 var errInconsistentCardinality = errors.New("inconsistent label cardinality")
 
-func makeInconsistentCardinalityError(fqName string, labels, labelValues []string) error {
-	return fmt.Errorf(
-		"%s: %q has %d variable labels named %q but %d values %q were provided",
-		errInconsistentCardinality, fqName,
-		len(labels), labels,
-		len(labelValues), labelValues,
-	)
-}
-
 func validateValuesInLabels(labels Labels, expectedNumberOfValues int) error {
 	if len(labels) != expectedNumberOfValues {
-		return fmt.Errorf(
-			"%s: expected %d label values but got %d in %#v",
-			errInconsistentCardinality, expectedNumberOfValues,
-			len(labels), labels,
-		)
+		return errInconsistentCardinality
 	}
 
 	for name, val := range labels {
@@ -66,11 +40,7 @@ func validateValuesInLabels(labels Labels, expectedNumberOfValues int) error {
 
 func validateLabelValues(vals []string, expectedNumberOfValues int) error {
 	if len(vals) != expectedNumberOfValues {
-		return fmt.Errorf(
-			"%s: expected %d label values but got %d in %#v",
-			errInconsistentCardinality, expectedNumberOfValues,
-			len(vals), vals,
-		)
+		return errInconsistentCardinality
 	}
 
 	for _, val := range vals {

vendor/github.com/prometheus/client_golang/prometheus/metric.go

@@ -15,9 +15,6 @@ package prometheus
 
 import (
 	"strings"
-	"time"
-
-	"github.com/golang/protobuf/proto"
 
 	dto "github.com/prometheus/client_model/go"
 )
@@ -46,8 +43,9 @@ type Metric interface {
 	// While populating dto.Metric, it is the responsibility of the
 	// implementation to ensure validity of the Metric protobuf (like valid
 	// UTF-8 strings or syntactically valid metric and label names). It is
-	// recommended to sort labels lexicographically. Callers of Write should
-	// still make sure of sorting if they depend on it.
+	// recommended to sort labels lexicographically. (Implementers may find
+	// LabelPairSorter useful for that.) Callers of Write should still make
+	// sure of sorting if they depend on it.
 	Write(*dto.Metric) error
 	// TODO(beorn7): The original rationale of passing in a pre-allocated
 	// dto.Metric protobuf to save allocations has disappeared. The
@@ -59,9 +57,8 @@ type Metric interface {
 // implementation XXX has its own XXXOpts type, but in most cases, it is just be
 // an alias of this type (which might change when the requirement arises.)
 //
-// It is mandatory to set Name to a non-empty string. All other fields are
-// optional and can safely be left at their zero value, although it is strongly
-// encouraged to set a Help string.
+// It is mandatory to set Name and Help to a non-empty string. All other fields
+// are optional and can safely be left at their zero value.
 type Opts struct {
 	// Namespace, Subsystem, and Name are components of the fully-qualified
 	// name of the Metric (created by joining these components with
@@ -72,7 +69,7 @@ type Opts struct {
 	Subsystem string
 	Name      string
 
-	// Help provides information about this metric.
+	// Help provides information about this metric. Mandatory!
 	//
 	// Metrics with the same fully-qualified name must have the same Help
 	// string.
@@ -113,22 +110,37 @@ func BuildFQName(namespace, subsystem, name string) string {
 	return name
 }
 
-// labelPairSorter implements sort.Interface. It is used to sort a slice of
-// dto.LabelPair pointers.
-type labelPairSorter []*dto.LabelPair
+// LabelPairSorter implements sort.Interface. It is used to sort a slice of
+// dto.LabelPair pointers. This is useful for implementing the Write method of
+// custom metrics.
+type LabelPairSorter []*dto.LabelPair
 
-func (s labelPairSorter) Len() int {
+func (s LabelPairSorter) Len() int {
 	return len(s)
 }
 
-func (s labelPairSorter) Swap(i, j int) {
+func (s LabelPairSorter) Swap(i, j int) {
 	s[i], s[j] = s[j], s[i]
 }
 
-func (s labelPairSorter) Less(i, j int) bool {
+func (s LabelPairSorter) Less(i, j int) bool {
 	return s[i].GetName() < s[j].GetName()
 }
 
+type hashSorter []uint64
+
+func (s hashSorter) Len() int {
+	return len(s)
+}
+
+func (s hashSorter) Swap(i, j int) {
+	s[i], s[j] = s[j], s[i]
+}
+
+func (s hashSorter) Less(i, j int) bool {
+	return s[i] < s[j]
+}
+
 type invalidMetric struct {
 	desc *Desc
 	err  error
@@ -144,31 +156,3 @@ func NewInvalidMetric(desc *Desc, err error) Metric {
 func (m *invalidMetric) Desc() *Desc { return m.desc }
 
 func (m *invalidMetric) Write(*dto.Metric) error { return m.err }
-
-type timestampedMetric struct {
-	Metric
-	t time.Time
-}
-
-func (m timestampedMetric) Write(pb *dto.Metric) error {
-	e := m.Metric.Write(pb)
-	pb.TimestampMs = proto.Int64(m.t.Unix()*1000 + int64(m.t.Nanosecond()/1000000))
-	return e
-}
-
-// NewMetricWithTimestamp returns a new Metric wrapping the provided Metric in a
-// way that it has an explicit timestamp set to the provided Time. This is only
-// useful in rare cases as the timestamp of a Prometheus metric should usually
-// be set by the Prometheus server during scraping. Exceptions include mirroring
-// metrics with given timestamps from other metric
-// sources.
-//
-// NewMetricWithTimestamp works best with MustNewConstMetric,
-// MustNewConstHistogram, and MustNewConstSummary, see example.
-//
-// Currently, the exposition formats used by Prometheus are limited to
-// millisecond resolution. Thus, the provided time will be rounded down to the
-// next full millisecond value.
-func NewMetricWithTimestamp(t time.Time, m Metric) Metric {
-	return timestampedMetric{Metric: m, t: t}
-}

vendor/github.com/prometheus/client_golang/prometheus/process_collector.go

@@ -13,61 +13,46 @@
 
 package prometheus
 
-import (
-	"errors"
-	"os"
-)
+import "github.com/prometheus/procfs"
 
 type processCollector struct {
+	pid             int
 	collectFn       func(chan<- Metric)
 	pidFn           func() (int, error)
-	reportErrors    bool
 	cpuTotal        *Desc
 	openFDs, maxFDs *Desc
-	vsize, maxVsize *Desc
-	rss             *Desc
+	vsize, rss      *Desc
 	startTime       *Desc
 }
 
-// ProcessCollectorOpts defines the behavior of a process metrics collector
-// created with NewProcessCollector.
-type ProcessCollectorOpts struct {
-	// PidFn returns the PID of the process the collector collects metrics
-	// for. It is called upon each collection. By default, the PID of the
-	// current process is used, as determined on construction time by
-	// calling os.Getpid().
-	PidFn func() (int, error)
-	// If non-empty, each of the collected metrics is prefixed by the
-	// provided string and an underscore ("_").
-	Namespace string
-	// If true, any error encountered during collection is reported as an
-	// invalid metric (see NewInvalidMetric). Otherwise, errors are ignored
-	// and the collected metrics will be incomplete. (Possibly, no metrics
-	// will be collected at all.) While that's usually not desired, it is
-	// appropriate for the common "mix-in" of process metrics, where process
-	// metrics are nice to have, but failing to collect them should not
-	// disrupt the collection of the remaining metrics.
-	ReportErrors bool
-}
-
 // NewProcessCollector returns a collector which exports the current state of
 // process metrics including CPU, memory and file descriptor usage as well as
-// the process start time. The detailed behavior is defined by the provided
-// ProcessCollectorOpts. The zero value of ProcessCollectorOpts creates a
-// collector for the current process with an empty namespace string and no error
-// reporting.
+// the process start time for the given process ID under the given namespace.
 //
-// The collector only works on operating systems with a Linux-style proc
-// filesystem and on Microsoft Windows. On other operating systems, it will not
-// collect any metrics.
-func NewProcessCollector(opts ProcessCollectorOpts) Collector {
+// Currently, the collector depends on a Linux-style proc filesystem and
+// therefore only exports metrics for Linux.
+func NewProcessCollector(pid int, namespace string) Collector {
+	return NewProcessCollectorPIDFn(
+		func() (int, error) { return pid, nil },
+		namespace,
+	)
+}
+
+// NewProcessCollectorPIDFn works like NewProcessCollector but the process ID is
+// determined on each collect anew by calling the given pidFn function.
+func NewProcessCollectorPIDFn(
+	pidFn func() (int, error),
+	namespace string,
+) Collector {
 	ns := ""
-	if len(opts.Namespace) > 0 {
-		ns = opts.Namespace + "_"
+	if len(namespace) > 0 {
+		ns = namespace + "_"
 	}
 
-	c := &processCollector{
-		reportErrors: opts.ReportErrors,
+	c := processCollector{
+		pidFn:     pidFn,
+		collectFn: func(chan<- Metric) {},
+
 		cpuTotal: NewDesc(
 			ns+"process_cpu_seconds_total",
 			"Total user and system CPU time spent in seconds.",
@@ -88,11 +73,6 @@ func NewProcessCollector(opts ProcessCollectorOpts) Collector {
 			"Virtual memory size in bytes.",
 			nil, nil,
 		),
-		maxVsize: NewDesc(
-			ns+"process_virtual_memory_max_bytes",
-			"Maximum amount of virtual memory available in bytes.",
-			nil, nil,
-		),
 		rss: NewDesc(
 			ns+"process_resident_memory_bytes",
 			"Resident memory size in bytes.",
@@ -105,23 +85,12 @@ func NewProcessCollector(opts ProcessCollectorOpts) Collector {
 		),
 	}
 
-	if opts.PidFn == nil {
-		pid := os.Getpid()
-		c.pidFn = func() (int, error) { return pid, nil }
-	} else {
-		c.pidFn = opts.PidFn
-	}
-
 	// Set up process metric collection if supported by the runtime.
-	if canCollectProcess() {
+	if _, err := procfs.NewStat(); err == nil {
 		c.collectFn = c.processCollect
-	} else {
-		c.collectFn = func(ch chan<- Metric) {
-			c.reportError(ch, nil, errors.New("process metrics not supported on this platform"))
-		}
 	}
 
-	return c
+	return &c
 }
 
 // Describe returns all descriptions of the collector.
@@ -130,7 +99,6 @@ func (c *processCollector) Describe(ch chan<- *Desc) {
 	ch <- c.openFDs
 	ch <- c.maxFDs
 	ch <- c.vsize
-	ch <- c.maxVsize
 	ch <- c.rss
 	ch <- c.startTime
 }
@@ -140,12 +108,33 @@ func (c *processCollector) Collect(ch chan<- Metric) {
 	c.collectFn(ch)
 }
 
-func (c *processCollector) reportError(ch chan<- Metric, desc *Desc, err error) {
-	if !c.reportErrors {
+// TODO(ts): Bring back error reporting by reverting 7faf9e7 as soon as the
+// client allows users to configure the error behavior.
+func (c *processCollector) processCollect(ch chan<- Metric) {
+	pid, err := c.pidFn()
+	if err != nil {
 		return
 	}
-	if desc == nil {
-		desc = NewInvalidDesc(err)
+
+	p, err := procfs.NewProc(pid)
+	if err != nil {
+		return
+	}
+
+	if stat, err := p.NewStat(); err == nil {
+		ch <- MustNewConstMetric(c.cpuTotal, CounterValue, stat.CPUTime())
+		ch <- MustNewConstMetric(c.vsize, GaugeValue, float64(stat.VirtualMemory()))
+		ch <- MustNewConstMetric(c.rss, GaugeValue, float64(stat.ResidentMemory()))
+		if startTime, err := stat.StartTime(); err == nil {
+			ch <- MustNewConstMetric(c.startTime, GaugeValue, startTime)
+		}
+	}
+
+	if fds, err := p.FileDescriptorsLen(); err == nil {
+		ch <- MustNewConstMetric(c.openFDs, GaugeValue, float64(fds))
+	}
+
+	if limits, err := p.NewLimits(); err == nil {
+		ch <- MustNewConstMetric(c.maxFDs, GaugeValue, float64(limits.OpenFiles))
 	}
-	ch <- NewInvalidMetric(desc, err)
 }

vendor/github.com/prometheus/client_golang/prometheus/process_collector_other.go

@@ -1,65 +0,0 @@
-// Copyright 2019 The Prometheus Authors
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-// http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-// +build !windows
-
-package prometheus
-
-import (
-	"github.com/prometheus/procfs"
-)
-
-func canCollectProcess() bool {
-	_, err := procfs.NewDefaultFS()
-	return err == nil
-}
-
-func (c *processCollector) processCollect(ch chan<- Metric) {
-	pid, err := c.pidFn()
-	if err != nil {
-		c.reportError(ch, nil, err)
-		return
-	}
-
-	p, err := procfs.NewProc(pid)
-	if err != nil {
-		c.reportError(ch, nil, err)
-		return
-	}
-
-	if stat, err := p.Stat(); err == nil {
-		ch <- MustNewConstMetric(c.cpuTotal, CounterValue, stat.CPUTime())
-		ch <- MustNewConstMetric(c.vsize, GaugeValue, float64(stat.VirtualMemory()))
-		ch <- MustNewConstMetric(c.rss, GaugeValue, float64(stat.ResidentMemory()))
-		if startTime, err := stat.StartTime(); err == nil {
-			ch <- MustNewConstMetric(c.startTime, GaugeValue, startTime)
-		} else {
-			c.reportError(ch, c.startTime, err)
-		}
-	} else {
-		c.reportError(ch, nil, err)
-	}
-
-	if fds, err := p.FileDescriptorsLen(); err == nil {
-		ch <- MustNewConstMetric(c.openFDs, GaugeValue, float64(fds))
-	} else {
-		c.reportError(ch, c.openFDs, err)
-	}
-
-	if limits, err := p.Limits(); err == nil {
-		ch <- MustNewConstMetric(c.maxFDs, GaugeValue, float64(limits.OpenFiles))
-		ch <- MustNewConstMetric(c.maxVsize, GaugeValue, float64(limits.AddressSpace))
-	} else {
-		c.reportError(ch, nil, err)
-	}
-}

vendor/github.com/prometheus/client_golang/prometheus/process_collector_windows.go

@@ -1,112 +0,0 @@
-// Copyright 2019 The Prometheus Authors
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-// http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-package prometheus
-
-import (
-	"syscall"
-	"unsafe"
-
-	"golang.org/x/sys/windows"
-)
-
-func canCollectProcess() bool {
-	return true
-}
-
-var (
-	modpsapi    = syscall.NewLazyDLL("psapi.dll")
-	modkernel32 = syscall.NewLazyDLL("kernel32.dll")
-
-	procGetProcessMemoryInfo  = modpsapi.NewProc("GetProcessMemoryInfo")
-	procGetProcessHandleCount = modkernel32.NewProc("GetProcessHandleCount")
-)
-
-type processMemoryCounters struct {
-	// https://docs.microsoft.com/en-us/windows/desktop/api/psapi/ns-psapi-_process_memory_counters_ex
-	_                          uint32
-	PageFaultCount             uint32
-	PeakWorkingSetSize         uint64
-	WorkingSetSize             uint64
-	QuotaPeakPagedPoolUsage    uint64
-	QuotaPagedPoolUsage        uint64
-	QuotaPeakNonPagedPoolUsage uint64
-	QuotaNonPagedPoolUsage     uint64
-	PagefileUsage              uint64
-	PeakPagefileUsage          uint64
-	PrivateUsage               uint64
-}
-
-func getProcessMemoryInfo(handle windows.Handle) (processMemoryCounters, error) {
-	mem := processMemoryCounters{}
-	r1, _, err := procGetProcessMemoryInfo.Call(
-		uintptr(handle),
-		uintptr(unsafe.Pointer(&mem)),
-		uintptr(unsafe.Sizeof(mem)),
-	)
-	if r1 != 1 {
-		return mem, err
-	} else {
-		return mem, nil
-	}
-}
-
-func getProcessHandleCount(handle windows.Handle) (uint32, error) {
-	var count uint32
-	r1, _, err := procGetProcessHandleCount.Call(
-		uintptr(handle),
-		uintptr(unsafe.Pointer(&count)),
-	)
-	if r1 != 1 {
-		return 0, err
-	} else {
-		return count, nil
-	}
-}
-
-func (c *processCollector) processCollect(ch chan<- Metric) {
-	h, err := windows.GetCurrentProcess()
-	if err != nil {
-		c.reportError(ch, nil, err)
-		return
-	}
-
-	var startTime, exitTime, kernelTime, userTime windows.Filetime
-	err = windows.GetProcessTimes(h, &startTime, &exitTime, &kernelTime, &userTime)
-	if err != nil {
-		c.reportError(ch, nil, err)
-		return
-	}
-	ch <- MustNewConstMetric(c.startTime, GaugeValue, float64(startTime.Nanoseconds()/1e9))
-	ch <- MustNewConstMetric(c.cpuTotal, CounterValue, fileTimeToSeconds(kernelTime)+fileTimeToSeconds(userTime))
-
-	mem, err := getProcessMemoryInfo(h)
-	if err != nil {
-		c.reportError(ch, nil, err)
-		return
-	}
-	ch <- MustNewConstMetric(c.vsize, GaugeValue, float64(mem.PrivateUsage))
-	ch <- MustNewConstMetric(c.rss, GaugeValue, float64(mem.WorkingSetSize))
-
-	handles, err := getProcessHandleCount(h)
-	if err != nil {
-		c.reportError(ch, nil, err)
-		return
-	}
-	ch <- MustNewConstMetric(c.openFDs, GaugeValue, float64(handles))
-	ch <- MustNewConstMetric(c.maxFDs, GaugeValue, float64(16*1024*1024)) // Windows has a hard-coded max limit, not per-process.
-}
-
-func fileTimeToSeconds(ft windows.Filetime) float64 {
-	return float64(uint64(ft.HighDateTime)<<32+uint64(ft.LowDateTime)) / 1e7
-}

vendor/github.com/prometheus/client_golang/prometheus/promhttp/delegator.go

@@ -38,6 +38,7 @@ type delegator interface {
 type responseWriterDelegator struct {
 	http.ResponseWriter
 
+	handler, method    string
 	status             int
 	written            int64
 	wroteHeader        bool
@@ -74,20 +75,17 @@ type closeNotifierDelegator struct{ *responseWriterDelegator }
 type flusherDelegator struct{ *responseWriterDelegator }
 type hijackerDelegator struct{ *responseWriterDelegator }
 type readerFromDelegator struct{ *responseWriterDelegator }
-type pusherDelegator struct{ *responseWriterDelegator }
 
-func (d closeNotifierDelegator) CloseNotify() <-chan bool {
-	//lint:ignore SA1019 http.CloseNotifier is deprecated but we don't want to
-	//remove support from client_golang yet.
+func (d *closeNotifierDelegator) CloseNotify() <-chan bool {
 	return d.ResponseWriter.(http.CloseNotifier).CloseNotify()
 }
-func (d flusherDelegator) Flush() {
+func (d *flusherDelegator) Flush() {
 	d.ResponseWriter.(http.Flusher).Flush()
 }
-func (d hijackerDelegator) Hijack() (net.Conn, *bufio.ReadWriter, error) {
+func (d *hijackerDelegator) Hijack() (net.Conn, *bufio.ReadWriter, error) {
 	return d.ResponseWriter.(http.Hijacker).Hijack()
 }
-func (d readerFromDelegator) ReadFrom(re io.Reader) (int64, error) {
+func (d *readerFromDelegator) ReadFrom(re io.Reader) (int64, error) {
 	if !d.wroteHeader {
 		d.WriteHeader(http.StatusOK)
 	}
@@ -95,9 +93,6 @@ func (d readerFromDelegator) ReadFrom(re io.Reader) (int64, error) {
 	d.written += n
 	return n, err
 }
-func (d pusherDelegator) Push(target string, opts *http.PushOptions) error {
-	return d.ResponseWriter.(http.Pusher).Push(target, opts)
-}
 
 var pickDelegator = make([]func(*responseWriterDelegator) delegator, 32)
 
@@ -107,34 +102,34 @@ func init() {
 		return d
 	}
 	pickDelegator[closeNotifier] = func(d *responseWriterDelegator) delegator { // 1
-		return closeNotifierDelegator{d}
+		return &closeNotifierDelegator{d}
 	}
 	pickDelegator[flusher] = func(d *responseWriterDelegator) delegator { // 2
-		return flusherDelegator{d}
+		return &flusherDelegator{d}
 	}
 	pickDelegator[flusher+closeNotifier] = func(d *responseWriterDelegator) delegator { // 3
 		return struct {
 			*responseWriterDelegator
 			http.Flusher
 			http.CloseNotifier
-		}{d, flusherDelegator{d}, closeNotifierDelegator{d}}
+		}{d, &flusherDelegator{d}, &closeNotifierDelegator{d}}
 	}
 	pickDelegator[hijacker] = func(d *responseWriterDelegator) delegator { // 4
-		return hijackerDelegator{d}
+		return &hijackerDelegator{d}
 	}
 	pickDelegator[hijacker+closeNotifier] = func(d *responseWriterDelegator) delegator { // 5
 		return struct {
 			*responseWriterDelegator
 			http.Hijacker
 			http.CloseNotifier
-		}{d, hijackerDelegator{d}, closeNotifierDelegator{d}}
+		}{d, &hijackerDelegator{d}, &closeNotifierDelegator{d}}
 	}
 	pickDelegator[hijacker+flusher] = func(d *responseWriterDelegator) delegator { // 6
 		return struct {
 			*responseWriterDelegator
 			http.Hijacker
 			http.Flusher
-		}{d, hijackerDelegator{d}, flusherDelegator{d}}
+		}{d, &hijackerDelegator{d}, &flusherDelegator{d}}
 	}
 	pickDelegator[hijacker+flusher+closeNotifier] = func(d *responseWriterDelegator) delegator { // 7
 		return struct {
@@ -142,7 +137,7 @@ func init() {
 			http.Hijacker
 			http.Flusher
 			http.CloseNotifier
-		}{d, hijackerDelegator{d}, flusherDelegator{d}, closeNotifierDelegator{d}}
+		}{d, &hijackerDelegator{d}, &flusherDelegator{d}, &closeNotifierDelegator{d}}
 	}
 	pickDelegator[readerFrom] = func(d *responseWriterDelegator) delegator { // 8
 		return readerFromDelegator{d}
@@ -152,14 +147,14 @@ func init() {
 			*responseWriterDelegator
 			io.ReaderFrom
 			http.CloseNotifier
-		}{d, readerFromDelegator{d}, closeNotifierDelegator{d}}
+		}{d, &readerFromDelegator{d}, &closeNotifierDelegator{d}}
 	}
 	pickDelegator[readerFrom+flusher] = func(d *responseWriterDelegator) delegator { // 10
 		return struct {
 			*responseWriterDelegator
 			io.ReaderFrom
 			http.Flusher
-		}{d, readerFromDelegator{d}, flusherDelegator{d}}
+		}{d, &readerFromDelegator{d}, &flusherDelegator{d}}
 	}
 	pickDelegator[readerFrom+flusher+closeNotifier] = func(d *responseWriterDelegator) delegator { // 11
 		return struct {
@@ -167,14 +162,14 @@ func init() {
 			io.ReaderFrom
 			http.Flusher
 			http.CloseNotifier
-		}{d, readerFromDelegator{d}, flusherDelegator{d}, closeNotifierDelegator{d}}
+		}{d, &readerFromDelegator{d}, &flusherDelegator{d}, &closeNotifierDelegator{d}}
 	}
 	pickDelegator[readerFrom+hijacker] = func(d *responseWriterDelegator) delegator { // 12
 		return struct {
 			*responseWriterDelegator
 			io.ReaderFrom
 			http.Hijacker
-		}{d, readerFromDelegator{d}, hijackerDelegator{d}}
+		}{d, &readerFromDelegator{d}, &hijackerDelegator{d}}
 	}
 	pickDelegator[readerFrom+hijacker+closeNotifier] = func(d *responseWriterDelegator) delegator { // 13
 		return struct {
@@ -182,7 +177,7 @@ func init() {
 			io.ReaderFrom
 			http.Hijacker
 			http.CloseNotifier
-		}{d, readerFromDelegator{d}, hijackerDelegator{d}, closeNotifierDelegator{d}}
+		}{d, &readerFromDelegator{d}, &hijackerDelegator{d}, &closeNotifierDelegator{d}}
 	}
 	pickDelegator[readerFrom+hijacker+flusher] = func(d *responseWriterDelegator) delegator { // 14
 		return struct {
@@ -190,7 +185,7 @@ func init() {
 			io.ReaderFrom
 			http.Hijacker
 			http.Flusher
-		}{d, readerFromDelegator{d}, hijackerDelegator{d}, flusherDelegator{d}}
+		}{d, &readerFromDelegator{d}, &hijackerDelegator{d}, &flusherDelegator{d}}
 	}
 	pickDelegator[readerFrom+hijacker+flusher+closeNotifier] = func(d *responseWriterDelegator) delegator { // 15
 		return struct {
@@ -199,159 +194,6 @@ func init() {
 			http.Hijacker
 			http.Flusher
 			http.CloseNotifier
-		}{d, readerFromDelegator{d}, hijackerDelegator{d}, flusherDelegator{d}, closeNotifierDelegator{d}}
-	}
-	pickDelegator[pusher] = func(d *responseWriterDelegator) delegator { // 16
-		return pusherDelegator{d}
-	}
-	pickDelegator[pusher+closeNotifier] = func(d *responseWriterDelegator) delegator { // 17
-		return struct {
-			*responseWriterDelegator
-			http.Pusher
-			http.CloseNotifier
-		}{d, pusherDelegator{d}, closeNotifierDelegator{d}}
-	}
-	pickDelegator[pusher+flusher] = func(d *responseWriterDelegator) delegator { // 18
-		return struct {
-			*responseWriterDelegator
-			http.Pusher
-			http.Flusher
-		}{d, pusherDelegator{d}, flusherDelegator{d}}
-	}
-	pickDelegator[pusher+flusher+closeNotifier] = func(d *responseWriterDelegator) delegator { // 19
-		return struct {
-			*responseWriterDelegator
-			http.Pusher
-			http.Flusher
-			http.CloseNotifier
-		}{d, pusherDelegator{d}, flusherDelegator{d}, closeNotifierDelegator{d}}
-	}
-	pickDelegator[pusher+hijacker] = func(d *responseWriterDelegator) delegator { // 20
-		return struct {
-			*responseWriterDelegator
-			http.Pusher
-			http.Hijacker
-		}{d, pusherDelegator{d}, hijackerDelegator{d}}
-	}
-	pickDelegator[pusher+hijacker+closeNotifier] = func(d *responseWriterDelegator) delegator { // 21
-		return struct {
-			*responseWriterDelegator
-			http.Pusher
-			http.Hijacker
-			http.CloseNotifier
-		}{d, pusherDelegator{d}, hijackerDelegator{d}, closeNotifierDelegator{d}}
-	}
-	pickDelegator[pusher+hijacker+flusher] = func(d *responseWriterDelegator) delegator { // 22
-		return struct {
-			*responseWriterDelegator
-			http.Pusher
-			http.Hijacker
-			http.Flusher
-		}{d, pusherDelegator{d}, hijackerDelegator{d}, flusherDelegator{d}}
-	}
-	pickDelegator[pusher+hijacker+flusher+closeNotifier] = func(d *responseWriterDelegator) delegator { //23
-		return struct {
-			*responseWriterDelegator
-			http.Pusher
-			http.Hijacker
-			http.Flusher
-			http.CloseNotifier
-		}{d, pusherDelegator{d}, hijackerDelegator{d}, flusherDelegator{d}, closeNotifierDelegator{d}}
-	}
-	pickDelegator[pusher+readerFrom] = func(d *responseWriterDelegator) delegator { // 24
-		return struct {
-			*responseWriterDelegator
-			http.Pusher
-			io.ReaderFrom
-		}{d, pusherDelegator{d}, readerFromDelegator{d}}
-	}
-	pickDelegator[pusher+readerFrom+closeNotifier] = func(d *responseWriterDelegator) delegator { // 25
-		return struct {
-			*responseWriterDelegator
-			http.Pusher
-			io.ReaderFrom
-			http.CloseNotifier
-		}{d, pusherDelegator{d}, readerFromDelegator{d}, closeNotifierDelegator{d}}
-	}
-	pickDelegator[pusher+readerFrom+flusher] = func(d *responseWriterDelegator) delegator { // 26
-		return struct {
-			*responseWriterDelegator
-			http.Pusher
-			io.ReaderFrom
-			http.Flusher
-		}{d, pusherDelegator{d}, readerFromDelegator{d}, flusherDelegator{d}}
-	}
-	pickDelegator[pusher+readerFrom+flusher+closeNotifier] = func(d *responseWriterDelegator) delegator { // 27
-		return struct {
-			*responseWriterDelegator
-			http.Pusher
-			io.ReaderFrom
-			http.Flusher
-			http.CloseNotifier
-		}{d, pusherDelegator{d}, readerFromDelegator{d}, flusherDelegator{d}, closeNotifierDelegator{d}}
-	}
-	pickDelegator[pusher+readerFrom+hijacker] = func(d *responseWriterDelegator) delegator { // 28
-		return struct {
-			*responseWriterDelegator
-			http.Pusher
-			io.ReaderFrom
-			http.Hijacker
-		}{d, pusherDelegator{d}, readerFromDelegator{d}, hijackerDelegator{d}}
-	}
-	pickDelegator[pusher+readerFrom+hijacker+closeNotifier] = func(d *responseWriterDelegator) delegator { // 29
-		return struct {
-			*responseWriterDelegator
-			http.Pusher
-			io.ReaderFrom
-			http.Hijacker
-			http.CloseNotifier
-		}{d, pusherDelegator{d}, readerFromDelegator{d}, hijackerDelegator{d}, closeNotifierDelegator{d}}
-	}
-	pickDelegator[pusher+readerFrom+hijacker+flusher] = func(d *responseWriterDelegator) delegator { // 30
-		return struct {
-			*responseWriterDelegator
-			http.Pusher
-			io.ReaderFrom
-			http.Hijacker
-			http.Flusher
-		}{d, pusherDelegator{d}, readerFromDelegator{d}, hijackerDelegator{d}, flusherDelegator{d}}
-	}
-	pickDelegator[pusher+readerFrom+hijacker+flusher+closeNotifier] = func(d *responseWriterDelegator) delegator { // 31
-		return struct {
-			*responseWriterDelegator
-			http.Pusher
-			io.ReaderFrom
-			http.Hijacker
-			http.Flusher
-			http.CloseNotifier
-		}{d, pusherDelegator{d}, readerFromDelegator{d}, hijackerDelegator{d}, flusherDelegator{d}, closeNotifierDelegator{d}}
+		}{d, &readerFromDelegator{d}, &hijackerDelegator{d}, &flusherDelegator{d}, &closeNotifierDelegator{d}}
 	}
 }
-
-func newDelegator(w http.ResponseWriter, observeWriteHeaderFunc func(int)) delegator {
-	d := &responseWriterDelegator{
-		ResponseWriter:     w,
-		observeWriteHeader: observeWriteHeaderFunc,
-	}
-
-	id := 0
-	//lint:ignore SA1019 http.CloseNotifier is deprecated but we don't want to
-	//remove support from client_golang yet.
-	if _, ok := w.(http.CloseNotifier); ok {
-		id += closeNotifier
-	}
-	if _, ok := w.(http.Flusher); ok {
-		id += flusher
-	}
-	if _, ok := w.(http.Hijacker); ok {
-		id += hijacker
-	}
-	if _, ok := w.(io.ReaderFrom); ok {
-		id += readerFrom
-	}
-	if _, ok := w.(http.Pusher); ok {
-		id += pusher
-	}
-
-	return pickDelegator[id](d)
-}

vendor/github.com/prometheus/client_golang/prometheus/promhttp/delegator_1_8.go

@@ -0,0 +1,181 @@
+// Copyright 2017 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// +build go1.8
+
+package promhttp
+
+import (
+	"io"
+	"net/http"
+)
+
+type pusherDelegator struct{ *responseWriterDelegator }
+
+func (d *pusherDelegator) Push(target string, opts *http.PushOptions) error {
+	return d.ResponseWriter.(http.Pusher).Push(target, opts)
+}
+
+func init() {
+	pickDelegator[pusher] = func(d *responseWriterDelegator) delegator { // 16
+		return &pusherDelegator{d}
+	}
+	pickDelegator[pusher+closeNotifier] = func(d *responseWriterDelegator) delegator { // 17
+		return struct {
+			*responseWriterDelegator
+			http.Pusher
+			http.CloseNotifier
+		}{d, &pusherDelegator{d}, &closeNotifierDelegator{d}}
+	}
+	pickDelegator[pusher+flusher] = func(d *responseWriterDelegator) delegator { // 18
+		return struct {
+			*responseWriterDelegator
+			http.Pusher
+			http.Flusher
+		}{d, &pusherDelegator{d}, &flusherDelegator{d}}
+	}
+	pickDelegator[pusher+flusher+closeNotifier] = func(d *responseWriterDelegator) delegator { // 19
+		return struct {
+			*responseWriterDelegator
+			http.Pusher
+			http.Flusher
+			http.CloseNotifier
+		}{d, &pusherDelegator{d}, &flusherDelegator{d}, &closeNotifierDelegator{d}}
+	}
+	pickDelegator[pusher+hijacker] = func(d *responseWriterDelegator) delegator { // 20
+		return struct {
+			*responseWriterDelegator
+			http.Pusher
+			http.Hijacker
+		}{d, &pusherDelegator{d}, &hijackerDelegator{d}}
+	}
+	pickDelegator[pusher+hijacker+closeNotifier] = func(d *responseWriterDelegator) delegator { // 21
+		return struct {
+			*responseWriterDelegator
+			http.Pusher
+			http.Hijacker
+			http.CloseNotifier
+		}{d, &pusherDelegator{d}, &hijackerDelegator{d}, &closeNotifierDelegator{d}}
+	}
+	pickDelegator[pusher+hijacker+flusher] = func(d *responseWriterDelegator) delegator { // 22
+		return struct {
+			*responseWriterDelegator
+			http.Pusher
+			http.Hijacker
+			http.Flusher
+		}{d, &pusherDelegator{d}, &hijackerDelegator{d}, &flusherDelegator{d}}
+	}
+	pickDelegator[pusher+hijacker+flusher+closeNotifier] = func(d *responseWriterDelegator) delegator { //23
+		return struct {
+			*responseWriterDelegator
+			http.Pusher
+			http.Hijacker
+			http.Flusher
+			http.CloseNotifier
+		}{d, &pusherDelegator{d}, &hijackerDelegator{d}, &flusherDelegator{d}, &closeNotifierDelegator{d}}
+	}
+	pickDelegator[pusher+readerFrom] = func(d *responseWriterDelegator) delegator { // 24
+		return struct {
+			*responseWriterDelegator
+			http.Pusher
+			io.ReaderFrom
+		}{d, &pusherDelegator{d}, &readerFromDelegator{d}}
+	}
+	pickDelegator[pusher+readerFrom+closeNotifier] = func(d *responseWriterDelegator) delegator { // 25
+		return struct {
+			*responseWriterDelegator
+			http.Pusher
+			io.ReaderFrom
+			http.CloseNotifier
+		}{d, &pusherDelegator{d}, &readerFromDelegator{d}, &closeNotifierDelegator{d}}
+	}
+	pickDelegator[pusher+readerFrom+flusher] = func(d *responseWriterDelegator) delegator { // 26
+		return struct {
+			*responseWriterDelegator
+			http.Pusher
+			io.ReaderFrom
+			http.Flusher
+		}{d, &pusherDelegator{d}, &readerFromDelegator{d}, &flusherDelegator{d}}
+	}
+	pickDelegator[pusher+readerFrom+flusher+closeNotifier] = func(d *responseWriterDelegator) delegator { // 27
+		return struct {
+			*responseWriterDelegator
+			http.Pusher
+			io.ReaderFrom
+			http.Flusher
+			http.CloseNotifier
+		}{d, &pusherDelegator{d}, &readerFromDelegator{d}, &flusherDelegator{d}, &closeNotifierDelegator{d}}
+	}
+	pickDelegator[pusher+readerFrom+hijacker] = func(d *responseWriterDelegator) delegator { // 28
+		return struct {
+			*responseWriterDelegator
+			http.Pusher
+			io.ReaderFrom
+			http.Hijacker
+		}{d, &pusherDelegator{d}, &readerFromDelegator{d}, &hijackerDelegator{d}}
+	}
+	pickDelegator[pusher+readerFrom+hijacker+closeNotifier] = func(d *responseWriterDelegator) delegator { // 29
+		return struct {
+			*responseWriterDelegator
+			http.Pusher
+			io.ReaderFrom
+			http.Hijacker
+			http.CloseNotifier
+		}{d, &pusherDelegator{d}, &readerFromDelegator{d}, &hijackerDelegator{d}, &closeNotifierDelegator{d}}
+	}
+	pickDelegator[pusher+readerFrom+hijacker+flusher] = func(d *responseWriterDelegator) delegator { // 30
+		return struct {
+			*responseWriterDelegator
+			http.Pusher
+			io.ReaderFrom
+			http.Hijacker
+			http.Flusher
+		}{d, &pusherDelegator{d}, &readerFromDelegator{d}, &hijackerDelegator{d}, &flusherDelegator{d}}
+	}
+	pickDelegator[pusher+readerFrom+hijacker+flusher+closeNotifier] = func(d *responseWriterDelegator) delegator { // 31
+		return struct {
+			*responseWriterDelegator
+			http.Pusher
+			io.ReaderFrom
+			http.Hijacker
+			http.Flusher
+			http.CloseNotifier
+		}{d, &pusherDelegator{d}, &readerFromDelegator{d}, &hijackerDelegator{d}, &flusherDelegator{d}, &closeNotifierDelegator{d}}
+	}
+}
+
+func newDelegator(w http.ResponseWriter, observeWriteHeaderFunc func(int)) delegator {
+	d := &responseWriterDelegator{
+		ResponseWriter:     w,
+		observeWriteHeader: observeWriteHeaderFunc,
+	}
+
+	id := 0
+	if _, ok := w.(http.CloseNotifier); ok {
+		id += closeNotifier
+	}
+	if _, ok := w.(http.Flusher); ok {
+		id += flusher
+	}
+	if _, ok := w.(http.Hijacker); ok {
+		id += hijacker
+	}
+	if _, ok := w.(io.ReaderFrom); ok {
+		id += readerFrom
+	}
+	if _, ok := w.(http.Pusher); ok {
+		id += pusher
+	}
+
+	return pickDelegator[id](d)
+}

vendor/github.com/prometheus/client_golang/prometheus/promhttp/delegator_pre_1_8.go

@@ -0,0 +1,44 @@
+// Copyright 2017 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// +build !go1.8
+
+package promhttp
+
+import (
+	"io"
+	"net/http"
+)
+
+func newDelegator(w http.ResponseWriter, observeWriteHeaderFunc func(int)) delegator {
+	d := &responseWriterDelegator{
+		ResponseWriter:     w,
+		observeWriteHeader: observeWriteHeaderFunc,
+	}
+
+	id := 0
+	if _, ok := w.(http.CloseNotifier); ok {
+		id += closeNotifier
+	}
+	if _, ok := w.(http.Flusher); ok {
+		id += flusher
+	}
+	if _, ok := w.(http.Hijacker); ok {
+		id += hijacker
+	}
+	if _, ok := w.(io.ReaderFrom); ok {
+		id += readerFrom
+	}
+
+	return pickDelegator[id](d)
+}

vendor/github.com/prometheus/client_golang/prometheus/promhttp/http.go

@@ -32,6 +32,7 @@
 package promhttp
 
 import (
+	"bytes"
 	"compress/gzip"
 	"fmt"
 	"io"
@@ -47,14 +48,24 @@ import (
 
 const (
 	contentTypeHeader     = "Content-Type"
+	contentLengthHeader   = "Content-Length"
 	contentEncodingHeader = "Content-Encoding"
 	acceptEncodingHeader  = "Accept-Encoding"
 )
 
-var gzipPool = sync.Pool{
-	New: func() interface{} {
-		return gzip.NewWriter(nil)
-	},
+var bufPool sync.Pool
+
+func getBuf() *bytes.Buffer {
+	buf := bufPool.Get()
+	if buf == nil {
+		return &bytes.Buffer{}
+	}
+	return buf.(*bytes.Buffer)
+}
+
+func giveBuf(buf *bytes.Buffer) {
+	buf.Reset()
+	bufPool.Put(buf)
 }
 
 // Handler returns an http.Handler for the prometheus.DefaultGatherer, using
@@ -84,107 +95,83 @@ func Handler() http.Handler {
 // instrumentation. Use the InstrumentMetricHandler function to apply the same
 // kind of instrumentation as it is used by the Handler function.
 func HandlerFor(reg prometheus.Gatherer, opts HandlerOpts) http.Handler {
-	var (
-		inFlightSem chan struct{}
-		errCnt      = prometheus.NewCounterVec(
-			prometheus.CounterOpts{
-				Name: "promhttp_metric_handler_errors_total",
-				Help: "Total number of internal errors encountered by the promhttp metric handler.",
-			},
-			[]string{"cause"},
-		)
-	)
-
+	var inFlightSem chan struct{}
 	if opts.MaxRequestsInFlight > 0 {
 		inFlightSem = make(chan struct{}, opts.MaxRequestsInFlight)
 	}
-	if opts.Registry != nil {
-		// Initialize all possibilites that can occur below.
-		errCnt.WithLabelValues("gathering")
-		errCnt.WithLabelValues("encoding")
-		if err := opts.Registry.Register(errCnt); err != nil {
-			if are, ok := err.(prometheus.AlreadyRegisteredError); ok {
-				errCnt = are.ExistingCollector.(*prometheus.CounterVec)
-			} else {
-				panic(err)
-			}
-		}
-	}
 
-	h := http.HandlerFunc(func(rsp http.ResponseWriter, req *http.Request) {
+	h := http.HandlerFunc(func(w http.ResponseWriter, req *http.Request) {
 		if inFlightSem != nil {
 			select {
 			case inFlightSem <- struct{}{}: // All good, carry on.
 				defer func() { <-inFlightSem }()
 			default:
-				http.Error(rsp, fmt.Sprintf(
+				http.Error(w, fmt.Sprintf(
 					"Limit of concurrent requests reached (%d), try again later.", opts.MaxRequestsInFlight,
 				), http.StatusServiceUnavailable)
 				return
 			}
 		}
+
 		mfs, err := reg.Gather()
 		if err != nil {
 			if opts.ErrorLog != nil {
 				opts.ErrorLog.Println("error gathering metrics:", err)
 			}
-			errCnt.WithLabelValues("gathering").Inc()
 			switch opts.ErrorHandling {
 			case PanicOnError:
 				panic(err)
 			case ContinueOnError:
 				if len(mfs) == 0 {
-					// Still report the error if no metrics have been gathered.
-					httpError(rsp, err)
+					http.Error(w, "No metrics gathered, last error:\n\n"+err.Error(), http.StatusInternalServerError)
 					return
 				}
 			case HTTPErrorOnError:
-				httpError(rsp, err)
+				http.Error(w, "An error has occurred during metrics gathering:\n\n"+err.Error(), http.StatusInternalServerError)
 				return
 			}
 		}
 
 		contentType := expfmt.Negotiate(req.Header)
-		header := rsp.Header()
-		header.Set(contentTypeHeader, string(contentType))
-
-		w := io.Writer(rsp)
-		if !opts.DisableCompression && gzipAccepted(req.Header) {
-			header.Set(contentEncodingHeader, "gzip")
-			gz := gzipPool.Get().(*gzip.Writer)
-			defer gzipPool.Put(gz)
-
-			gz.Reset(w)
-			defer gz.Close()
-
-			w = gz
-		}
-
-		enc := expfmt.NewEncoder(w, contentType)
-
+		buf := getBuf()
+		defer giveBuf(buf)
+		writer, encoding := decorateWriter(req, buf, opts.DisableCompression)
+		enc := expfmt.NewEncoder(writer, contentType)
 		var lastErr error
 		for _, mf := range mfs {
 			if err := enc.Encode(mf); err != nil {
 				lastErr = err
 				if opts.ErrorLog != nil {
-					opts.ErrorLog.Println("error encoding and sending metric family:", err)
+					opts.ErrorLog.Println("error encoding metric family:", err)
 				}
-				errCnt.WithLabelValues("encoding").Inc()
 				switch opts.ErrorHandling {
 				case PanicOnError:
 					panic(err)
 				case ContinueOnError:
 					// Handled later.
 				case HTTPErrorOnError:
-					httpError(rsp, err)
+					http.Error(w, "An error has occurred during metrics encoding:\n\n"+err.Error(), http.StatusInternalServerError)
 					return
 				}
 			}
 		}
-
-		if lastErr != nil {
-			httpError(rsp, lastErr)
+		if closer, ok := writer.(io.Closer); ok {
+			closer.Close()
 		}
+		if lastErr != nil && buf.Len() == 0 {
+			http.Error(w, "No metrics encoded, last error:\n\n"+lastErr.Error(), http.StatusInternalServerError)
+			return
+		}
+		header := w.Header()
+		header.Set(contentTypeHeader, string(contentType))
+		header.Set(contentLengthHeader, fmt.Sprint(buf.Len()))
+		if encoding != "" {
+			header.Set(contentEncodingHeader, encoding)
+		}
+		if _, err := w.Write(buf.Bytes()); err != nil && opts.ErrorLog != nil {
+			opts.ErrorLog.Println("error while sending encoded metrics:", err)
+		}
+		// TODO(beorn7): Consider streaming serving of metrics.
 	})
 
 	if opts.Timeout <= 0 {
@@ -260,12 +247,9 @@ const (
 	// Ignore errors and try to serve as many metrics as possible.  However,
 	// if no metrics can be served, serve an HTTP status code 500 and the
 	// last error message in the body. Only use this in deliberate "best
-	// effort" metrics collection scenarios. In this case, it is highly
-	// recommended to provide other means of detecting errors: By setting an
-	// ErrorLog in HandlerOpts, the errors are logged. By providing a
-	// Registry in HandlerOpts, the exposed metrics include an error counter
-	// "promhttp_metric_handler_errors_total", which can be used for
-	// alerts.
+	// effort" metrics collection scenarios. It is recommended to at least
+	// log errors (by providing an ErrorLog in HandlerOpts) to not mask
+	// errors completely.
 	ContinueOnError
 	// Panic upon the first error encountered (useful for "crash only" apps).
 	PanicOnError
@@ -288,18 +272,6 @@ type HandlerOpts struct {
 	// logged regardless of the configured ErrorHandling provided ErrorLog
 	// is not nil.
 	ErrorHandling HandlerErrorHandling
-	// If Registry is not nil, it is used to register a metric
-	// "promhttp_metric_handler_errors_total", partitioned by "cause". A
-	// failed registration causes a panic. Note that this error counter is
-	// different from the instrumentation you get from the various
-	// InstrumentHandler... helpers. It counts errors that don't necessarily
-	// result in a non-2xx HTTP status code. There are two typical cases:
-	// (1) Encoding errors that only happen after streaming of the HTTP body
-	// has already started (and the status code 200 has been sent). This
-	// should only happen with custom collectors. (2) Collection errors with
-	// no effect on the HTTP status code because ErrorHandling is set to
-	// ContinueOnError.
-	Registry prometheus.Registerer
 	// If DisableCompression is true, the handler will never compress the
 	// response, even if requested by the client.
 	DisableCompression bool
@@ -308,7 +280,7 @@ type HandlerOpts struct {
 	// Service Unavailable and a suitable message in the body. If
 	// MaxRequestsInFlight is 0 or negative, no limit is applied.
 	MaxRequestsInFlight int
-	// If handling a request takes longer than Timeout, it is responded to
+	// If handling a request takes longer than Timeout, it is repsonded to
 	// with 503 ServiceUnavailable and a suitable Message. No timeout is
 	// applied if Timeout is 0 or negative. Note that with the current
 	// implementation, reaching the timeout simply ends the HTTP requests as
@@ -320,30 +292,20 @@ type HandlerOpts struct {
 	Timeout time.Duration
 }
 
-// gzipAccepted returns whether the client will accept gzip-encoded content.
-func gzipAccepted(header http.Header) bool {
-	a := header.Get(acceptEncodingHeader)
-	parts := strings.Split(a, ",")
+// decorateWriter wraps a writer to handle gzip compression if requested.  It
+// returns the decorated writer and the appropriate "Content-Encoding" header
+// (which is empty if no compression is enabled).
+func decorateWriter(request *http.Request, writer io.Writer, compressionDisabled bool) (io.Writer, string) {
+	if compressionDisabled {
+		return writer, ""
+	}
+	header := request.Header.Get(acceptEncodingHeader)
+	parts := strings.Split(header, ",")
 	for _, part := range parts {
-		part = strings.TrimSpace(part)
+		part := strings.TrimSpace(part)
 		if part == "gzip" || strings.HasPrefix(part, "gzip;") {
-			return true
+			return gzip.NewWriter(writer), "gzip"
 		}
 	}
-	return false
-}
-
-// httpError removes any content-encoding header and then calls http.Error with
-// the provided error and http.StatusInternalServerErrer. Error contents is
-// supposed to be uncompressed plain text. However, same as with a plain
-// http.Error, any header settings will be void if the header has already been
-// sent. The error message will still be written to the writer, but it will
-// probably be of limited use.
-func httpError(rsp http.ResponseWriter, err error) {
-	rsp.Header().Del(contentEncodingHeader)
-	http.Error(
-		rsp,
-		"An error has occurred while serving metrics:\n\n"+err.Error(),
-		http.StatusInternalServerError,
-	)
+	return writer, ""
 }

vendor/github.com/prometheus/client_golang/prometheus/promhttp/instrument_client.go

@@ -14,9 +14,7 @@
 package promhttp
 
 import (
-	"crypto/tls"
 	"net/http"
-	"net/http/httptrace"
 	"time"
 
 	"github.com/prometheus/client_golang/prometheus"
@@ -97,123 +95,3 @@ func InstrumentRoundTripperDuration(obs prometheus.ObserverVec, next http.RoundT
 		return resp, err
 	})
 }
-
-// InstrumentTrace is used to offer flexibility in instrumenting the available
-// httptrace.ClientTrace hook functions. Each function is passed a float64
-// representing the time in seconds since the start of the http request. A user
-// may choose to use separately buckets Histograms, or implement custom
-// instance labels on a per function basis.
-type InstrumentTrace struct {
-	GotConn              func(float64)
-	PutIdleConn          func(float64)
-	GotFirstResponseByte func(float64)
-	Got100Continue       func(float64)
-	DNSStart             func(float64)
-	DNSDone              func(float64)
-	ConnectStart         func(float64)
-	ConnectDone          func(float64)
-	TLSHandshakeStart    func(float64)
-	TLSHandshakeDone     func(float64)
-	WroteHeaders         func(float64)
-	Wait100Continue      func(float64)
-	WroteRequest         func(float64)
-}
-
-// InstrumentRoundTripperTrace is a middleware that wraps the provided
-// RoundTripper and reports times to hook functions provided in the
-// InstrumentTrace struct. Hook functions that are not present in the provided
-// InstrumentTrace struct are ignored. Times reported to the hook functions are
-// time since the start of the request. Only with Go1.9+, those times are
-// guaranteed to never be negative. (Earlier Go versions are not using a
-// monotonic clock.) Note that partitioning of Histograms is expensive and
-// should be used judiciously.
-//
-// For hook functions that receive an error as an argument, no observations are
-// made in the event of a non-nil error value.
-//
-// See the example for ExampleInstrumentRoundTripperDuration for example usage.
-func InstrumentRoundTripperTrace(it *InstrumentTrace, next http.RoundTripper) RoundTripperFunc {
-	return RoundTripperFunc(func(r *http.Request) (*http.Response, error) {
-		start := time.Now()
-
-		trace := &httptrace.ClientTrace{
-			GotConn: func(_ httptrace.GotConnInfo) {
-				if it.GotConn != nil {
-					it.GotConn(time.Since(start).Seconds())
-				}
-			},
-			PutIdleConn: func(err error) {
-				if err != nil {
-					return
-				}
-				if it.PutIdleConn != nil {
-					it.PutIdleConn(time.Since(start).Seconds())
-				}
-			},
-			DNSStart: func(_ httptrace.DNSStartInfo) {
-				if it.DNSStart != nil {
-					it.DNSStart(time.Since(start).Seconds())
-				}
-			},
-			DNSDone: func(_ httptrace.DNSDoneInfo) {
-				if it.DNSDone != nil {
-					it.DNSDone(time.Since(start).Seconds())
-				}
-			},
-			ConnectStart: func(_, _ string) {
-				if it.ConnectStart != nil {
-					it.ConnectStart(time.Since(start).Seconds())
-				}
-			},
-			ConnectDone: func(_, _ string, err error) {
-				if err != nil {
-					return
-				}
-				if it.ConnectDone != nil {
-					it.ConnectDone(time.Since(start).Seconds())
-				}
-			},
-			GotFirstResponseByte: func() {
-				if it.GotFirstResponseByte != nil {
-					it.GotFirstResponseByte(time.Since(start).Seconds())
-				}
-			},
-			Got100Continue: func() {
-				if it.Got100Continue != nil {
-					it.Got100Continue(time.Since(start).Seconds())
-				}
-			},
-			TLSHandshakeStart: func() {
-				if it.TLSHandshakeStart != nil {
-					it.TLSHandshakeStart(time.Since(start).Seconds())
-				}
-			},
-			TLSHandshakeDone: func(_ tls.ConnectionState, err error) {
-				if err != nil {
-					return
-				}
-				if it.TLSHandshakeDone != nil {
-					it.TLSHandshakeDone(time.Since(start).Seconds())
-				}
-			},
-			WroteHeaders: func() {
-				if it.WroteHeaders != nil {
-					it.WroteHeaders(time.Since(start).Seconds())
-				}
-			},
-			Wait100Continue: func() {
-				if it.Wait100Continue != nil {
-					it.Wait100Continue(time.Since(start).Seconds())
-				}
-			},
-			WroteRequest: func(_ httptrace.WroteRequestInfo) {
-				if it.WroteRequest != nil {
-					it.WroteRequest(time.Since(start).Seconds())
-				}
-			},
-		}
-		r = r.WithContext(httptrace.WithClientTrace(r.Context(), trace))
-
-		return next.RoundTrip(r)
-	})
-}

vendor/github.com/prometheus/client_golang/prometheus/promhttp/instrument_client_1_8.go

@@ -0,0 +1,144 @@
+// Copyright 2017 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// +build go1.8
+
+package promhttp
+
+import (
+	"context"
+	"crypto/tls"
+	"net/http"
+	"net/http/httptrace"
+	"time"
+)
+
+// InstrumentTrace is used to offer flexibility in instrumenting the available
+// httptrace.ClientTrace hook functions. Each function is passed a float64
+// representing the time in seconds since the start of the http request. A user
+// may choose to use separately buckets Histograms, or implement custom
+// instance labels on a per function basis.
+type InstrumentTrace struct {
+	GotConn              func(float64)
+	PutIdleConn          func(float64)
+	GotFirstResponseByte func(float64)
+	Got100Continue       func(float64)
+	DNSStart             func(float64)
+	DNSDone              func(float64)
+	ConnectStart         func(float64)
+	ConnectDone          func(float64)
+	TLSHandshakeStart    func(float64)
+	TLSHandshakeDone     func(float64)
+	WroteHeaders         func(float64)
+	Wait100Continue      func(float64)
+	WroteRequest         func(float64)
+}
+
+// InstrumentRoundTripperTrace is a middleware that wraps the provided
+// RoundTripper and reports times to hook functions provided in the
+// InstrumentTrace struct. Hook functions that are not present in the provided
+// InstrumentTrace struct are ignored. Times reported to the hook functions are
+// time since the start of the request. Only with Go1.9+, those times are
+// guaranteed to never be negative. (Earlier Go versions are not using a
+// monotonic clock.) Note that partitioning of Histograms is expensive and
+// should be used judiciously.
+//
+// For hook functions that receive an error as an argument, no observations are
+// made in the event of a non-nil error value.
+//
+// See the example for ExampleInstrumentRoundTripperDuration for example usage.
+func InstrumentRoundTripperTrace(it *InstrumentTrace, next http.RoundTripper) RoundTripperFunc {
+	return RoundTripperFunc(func(r *http.Request) (*http.Response, error) {
+		start := time.Now()
+
+		trace := &httptrace.ClientTrace{
+			GotConn: func(_ httptrace.GotConnInfo) {
+				if it.GotConn != nil {
+					it.GotConn(time.Since(start).Seconds())
+				}
+			},
+			PutIdleConn: func(err error) {
+				if err != nil {
+					return
+				}
+				if it.PutIdleConn != nil {
+					it.PutIdleConn(time.Since(start).Seconds())
+				}
+			},
+			DNSStart: func(_ httptrace.DNSStartInfo) {
+				if it.DNSStart != nil {
+					it.DNSStart(time.Since(start).Seconds())
+				}
+			},
+			DNSDone: func(_ httptrace.DNSDoneInfo) {
+				if it.DNSStart != nil {
+					it.DNSStart(time.Since(start).Seconds())
+				}
+			},
+			ConnectStart: func(_, _ string) {
+				if it.ConnectStart != nil {
+					it.ConnectStart(time.Since(start).Seconds())
+				}
+			},
+			ConnectDone: func(_, _ string, err error) {
+				if err != nil {
+					return
+				}
+				if it.ConnectDone != nil {
+					it.ConnectDone(time.Since(start).Seconds())
+				}
+			},
+			GotFirstResponseByte: func() {
+				if it.GotFirstResponseByte != nil {
+					it.GotFirstResponseByte(time.Since(start).Seconds())
+				}
+			},
+			Got100Continue: func() {
+				if it.Got100Continue != nil {
+					it.Got100Continue(time.Since(start).Seconds())
+				}
+			},
+			TLSHandshakeStart: func() {
+				if it.TLSHandshakeStart != nil {
+					it.TLSHandshakeStart(time.Since(start).Seconds())
+				}
+			},
+			TLSHandshakeDone: func(_ tls.ConnectionState, err error) {
+				if err != nil {
+					return
+				}
+				if it.TLSHandshakeDone != nil {
+					it.TLSHandshakeDone(time.Since(start).Seconds())
+				}
+			},
+			WroteHeaders: func() {
+				if it.WroteHeaders != nil {
+					it.WroteHeaders(time.Since(start).Seconds())
+				}
+			},
+			Wait100Continue: func() {
+				if it.Wait100Continue != nil {
+					it.Wait100Continue(time.Since(start).Seconds())
+				}
+			},
+			WroteRequest: func(_ httptrace.WroteRequestInfo) {
+				if it.WroteRequest != nil {
+					it.WroteRequest(time.Since(start).Seconds())
+				}
+			},
+		}
+		r = r.WithContext(httptrace.WithClientTrace(context.Background(), trace))
+
+		return next.RoundTrip(r)
+	})
+}

vendor/github.com/prometheus/client_golang/prometheus/registry.go

@@ -15,22 +15,17 @@ package prometheus
 
 import (
 	"bytes"
+	"errors"
 	"fmt"
-	"io/ioutil"
 	"os"
-	"path/filepath"
 	"runtime"
 	"sort"
-	"strings"
 	"sync"
 	"unicode/utf8"
 
 	"github.com/golang/protobuf/proto"
-	"github.com/prometheus/common/expfmt"
 
 	dto "github.com/prometheus/client_model/go"
-
-	"github.com/prometheus/client_golang/prometheus/internal"
 )
 
 const (
@@ -43,13 +38,12 @@ const (
 // Registerer and Gatherer interface a number of convenience functions in this
 // package act on. Initially, both variables point to the same Registry, which
 // has a process collector (currently on Linux only, see NewProcessCollector)
-// and a Go collector (see NewGoCollector, in particular the note about
-// stop-the-world implication with Go versions older than 1.9) already
-// registered. This approach to keep default instances as global state mirrors
-// the approach of other packages in the Go standard library. Note that there
-// are caveats. Change the variables with caution and only if you understand the
-// consequences. Users who want to avoid global state altogether should not use
-// the convenience functions and act on custom instances instead.
+// and a Go collector (see NewGoCollector) already registered. This approach to
+// keep default instances as global state mirrors the approach of other packages
+// in the Go standard library. Note that there are caveats. Change the variables
+// with caution and only if you understand the consequences. Users who want to
+// avoid global state altogether should not use the convenience functions and
+// act on custom instances instead.
 var (
 	defaultRegistry              = NewRegistry()
 	DefaultRegisterer Registerer = defaultRegistry
@@ -57,7 +51,7 @@ var (
 )
 
 func init() {
-	MustRegister(NewProcessCollector(ProcessCollectorOpts{}))
+	MustRegister(NewProcessCollector(os.Getpid(), ""))
 	MustRegister(NewGoCollector())
 }
 
@@ -73,8 +67,7 @@ func NewRegistry() *Registry {
 
 // NewPedanticRegistry returns a registry that checks during collection if each
 // collected Metric is consistent with its reported Desc, and if the Desc has
-// actually been registered with the registry. Unchecked Collectors (those whose
-// Describe methed does not yield any descriptors) are excluded from the check.
+// actually been registered with the registry.
 //
 // Usually, a Registry will be happy as long as the union of all collected
 // Metrics is consistent and valid even if some metrics are not consistent with
@@ -104,13 +97,8 @@ type Registerer interface {
 	// returned error is an instance of AlreadyRegisteredError, which
 	// contains the previously registered Collector.
 	//
-	// A Collector whose Describe method does not yield any Desc is treated
-	// as unchecked. Registration will always succeed. No check for
-	// re-registering (see previous paragraph) is performed. Thus, the
-	// caller is responsible for not double-registering the same unchecked
-	// Collector, and for providing a Collector that will not cause
-	// inconsistent metrics on collection. (This would lead to scrape
-	// errors.)
+	// It is in general not safe to register the same Collector multiple
+	// times concurrently.
 	Register(Collector) error
 	// MustRegister works like Register but registers any number of
 	// Collectors and panics upon the first registration that causes an
@@ -119,9 +107,7 @@ type Registerer interface {
 	// Unregister unregisters the Collector that equals the Collector passed
 	// in as an argument.  (Two Collectors are considered equal if their
 	// Describe method yields the same set of descriptors.) The function
-	// returns whether a Collector was unregistered. Note that an unchecked
-	// Collector cannot be unregistered (as its Describe method does not
-	// yield any descriptor).
+	// returns whether a Collector was unregistered.
 	//
 	// Note that even after unregistering, it will not be possible to
 	// register a new Collector that is inconsistent with the unregistered
@@ -139,23 +125,15 @@ type Registerer interface {
 type Gatherer interface {
 	// Gather calls the Collect method of the registered Collectors and then
 	// gathers the collected metrics into a lexicographically sorted slice
-	// of uniquely named MetricFamily protobufs. Gather ensures that the
-	// returned slice is valid and self-consistent so that it can be used
-	// for valid exposition. As an exception to the strict consistency
-	// requirements described for metric.Desc, Gather will tolerate
-	// different sets of label names for metrics of the same metric family.
-	//
-	// Even if an error occurs, Gather attempts to gather as many metrics as
-	// possible. Hence, if a non-nil error is returned, the returned
-	// MetricFamily slice could be nil (in case of a fatal error that
-	// prevented any meaningful metric collection) or contain a number of
-	// MetricFamily protobufs, some of which might be incomplete, and some
-	// might be missing altogether. The returned error (which might be a
-	// MultiError) explains the details. Note that this is mostly useful for
-	// debugging purposes. If the gathered protobufs are to be used for
-	// exposition in actual monitoring, it is almost always better to not
-	// expose an incomplete result and instead disregard the returned
-	// MetricFamily protobufs in case the returned error is non-nil.
+	// of MetricFamily protobufs. Even if an error occurs, Gather attempts
+	// to gather as many metrics as possible. Hence, if a non-nil error is
+	// returned, the returned MetricFamily slice could be nil (in case of a
+	// fatal error that prevented any meaningful metric collection) or
+	// contain a number of MetricFamily protobufs, some of which might be
+	// incomplete, and some might be missing altogether. The returned error
+	// (which might be a MultiError) explains the details. In scenarios
+	// where complete collection is critical, the returned MetricFamily
+	// protobufs should be disregarded if the returned error is non-nil.
 	Gather() ([]*dto.MetricFamily, error)
 }
 
@@ -256,7 +234,6 @@ type Registry struct {
 	collectorsByID        map[uint64]Collector // ID is a hash of the descIDs.
 	descIDs               map[uint64]struct{}
 	dimHashesByName       map[string]uint64
-	uncheckedCollectors   []Collector
 	pedanticChecksEnabled bool
 }
 
@@ -274,12 +251,7 @@ func (r *Registry) Register(c Collector) error {
 		close(descChan)
 	}()
 	r.mtx.Lock()
-	defer func() {
-		// Drain channel in case of premature return to not leak a goroutine.
-		for range descChan {
-		}
-		r.mtx.Unlock()
-	}()
+	defer r.mtx.Unlock()
 	// Conduct various tests...
 	for desc := range descChan {
 
@@ -319,23 +291,14 @@ func (r *Registry) Register(c Collector) error {
 			}
 		}
 	}
-	// A Collector yielding no Desc at all is considered unchecked.
+	// Did anything happen at all?
 	if len(newDescIDs) == 0 {
-		r.uncheckedCollectors = append(r.uncheckedCollectors, c)
-		return nil
+		return errors.New("collector has no descriptors")
 	}
 	if existing, exists := r.collectorsByID[collectorID]; exists {
-		switch e := existing.(type) {
-		case *wrappingCollector:
-			return AlreadyRegisteredError{
-				ExistingCollector: e.unwrapRecursively(),
-				NewCollector:      c,
-			}
-		default:
-			return AlreadyRegisteredError{
-				ExistingCollector: e,
-				NewCollector:      c,
-			}
+		return AlreadyRegisteredError{
+			ExistingCollector: existing,
+			NewCollector:      c,
 		}
 	}
 	// If the collectorID is new, but at least one of the descs existed
@@ -404,24 +367,20 @@ func (r *Registry) MustRegister(cs ...Collector) {
 // Gather implements Gatherer.
 func (r *Registry) Gather() ([]*dto.MetricFamily, error) {
 	var (
-		checkedMetricChan   = make(chan Metric, capMetricChan)
-		uncheckedMetricChan = make(chan Metric, capMetricChan)
-		metricHashes        = map[uint64]struct{}{}
-		wg                  sync.WaitGroup
-		errs                MultiError          // The collected errors to return in the end.
-		registeredDescIDs   map[uint64]struct{} // Only used for pedantic checks
+		metricChan        = make(chan Metric, capMetricChan)
+		metricHashes      = map[uint64]struct{}{}
+		dimHashes         = map[string]uint64{}
+		wg                sync.WaitGroup
+		errs              MultiError          // The collected errors to return in the end.
+		registeredDescIDs map[uint64]struct{} // Only used for pedantic checks
 	)
 
 	r.mtx.RLock()
-	goroutineBudget := len(r.collectorsByID) + len(r.uncheckedCollectors)
+	goroutineBudget := len(r.collectorsByID)
 	metricFamiliesByName := make(map[string]*dto.MetricFamily, len(r.dimHashesByName))
-	checkedCollectors := make(chan Collector, len(r.collectorsByID))
-	uncheckedCollectors := make(chan Collector, len(r.uncheckedCollectors))
+	collectors := make(chan Collector, len(r.collectorsByID))
 	for _, collector := range r.collectorsByID {
-		checkedCollectors <- collector
-	}
-	for _, collector := range r.uncheckedCollectors {
-		uncheckedCollectors <- collector
+		collectors <- collector
 	}
 	// In case pedantic checks are enabled, we have to copy the map before
 	// giving up the RLock.
@@ -438,14 +397,12 @@ func (r *Registry) Gather() ([]*dto.MetricFamily, error) {
 	collectWorker := func() {
 		for {
 			select {
-			case collector := <-checkedCollectors:
-				collector.Collect(checkedMetricChan)
-			case collector := <-uncheckedCollectors:
-				collector.Collect(uncheckedMetricChan)
+			case collector := <-collectors:
+				collector.Collect(metricChan)
+				wg.Done()
 			default:
 				return
 			}
-			wg.Done()
 		}
 	}
 
@@ -453,128 +410,53 @@ func (r *Registry) Gather() ([]*dto.MetricFamily, error) {
 	go collectWorker()
 	goroutineBudget--
 
-	// Close checkedMetricChan and uncheckedMetricChan once all collectors
-	// are collected.
+	// Close the metricChan once all collectors are collected.
 	go func() {
 		wg.Wait()
-		close(checkedMetricChan)
-		close(uncheckedMetricChan)
+		close(metricChan)
 	}()
 
-	// Drain checkedMetricChan and uncheckedMetricChan in case of premature return.
+	// Drain metricChan in case of premature return.
 	defer func() {
-		if checkedMetricChan != nil {
-			for range checkedMetricChan {
-			}
-		}
-		if uncheckedMetricChan != nil {
-			for range uncheckedMetricChan {
-			}
+		for range metricChan {
 		}
 	}()
 
-	// Copy the channel references so we can nil them out later to remove
-	// them from the select statements below.
-	cmc := checkedMetricChan
-	umc := uncheckedMetricChan
-
+collectLoop:
 	for {
 		select {
-		case metric, ok := <-cmc:
+		case metric, ok := <-metricChan:
 			if !ok {
-				cmc = nil
-				break
+				// metricChan is closed, we are done.
+				break collectLoop
 			}
 			errs.Append(processMetric(
 				metric, metricFamiliesByName,
-				metricHashes,
+				metricHashes, dimHashes,
 				registeredDescIDs,
 			))
-		case metric, ok := <-umc:
-			if !ok {
-				umc = nil
-				break
-			}
-			errs.Append(processMetric(
-				metric, metricFamiliesByName,
-				metricHashes,
-				nil,
-			))
 		default:
-			if goroutineBudget <= 0 || len(checkedCollectors)+len(uncheckedCollectors) == 0 {
-				// All collectors are already being worked on or
+			if goroutineBudget <= 0 || len(collectors) == 0 {
+				// All collectors are aleady being worked on or
 				// we have already as many goroutines started as
-				// there are collectors. Do the same as above,
-				// just without the default.
-				select {
-				case metric, ok := <-cmc:
-					if !ok {
-						cmc = nil
-						break
-					}
+				// there are collectors. Just process metrics
+				// from now on.
+				for metric := range metricChan {
 					errs.Append(processMetric(
 						metric, metricFamiliesByName,
-						metricHashes,
+						metricHashes, dimHashes,
 						registeredDescIDs,
 					))
-				case metric, ok := <-umc:
-					if !ok {
-						umc = nil
-						break
-					}
-					errs.Append(processMetric(
-						metric, metricFamiliesByName,
-						metricHashes,
-						nil,
-					))
 				}
-				break
+				break collectLoop
 			}
 			// Start more workers.
 			go collectWorker()
 			goroutineBudget--
 			runtime.Gosched()
 		}
-		// Once both checkedMetricChan and uncheckdMetricChan are closed
-		// and drained, the contraption above will nil out cmc and umc,
-		// and then we can leave the collect loop here.
-		if cmc == nil && umc == nil {
-			break
-		}
 	}
-	return internal.NormalizeMetricFamilies(metricFamiliesByName), errs.MaybeUnwrap()
-}
-
-// WriteToTextfile calls Gather on the provided Gatherer, encodes the result in the
-// Prometheus text format, and writes it to a temporary file. Upon success, the
-// temporary file is renamed to the provided filename.
-//
-// This is intended for use with the textfile collector of the node exporter.
-// Note that the node exporter expects the filename to be suffixed with ".prom".
-func WriteToTextfile(filename string, g Gatherer) error {
-	tmp, err := ioutil.TempFile(filepath.Dir(filename), filepath.Base(filename))
-	if err != nil {
-		return err
-	}
-	defer os.Remove(tmp.Name())
-
-	mfs, err := g.Gather()
-	if err != nil {
-		return err
-	}
-	for _, mf := range mfs {
-		if _, err := expfmt.MetricFamilyToText(tmp, mf); err != nil {
-			return err
-		}
-	}
-	if err := tmp.Close(); err != nil {
-		return err
-	}
-
-	if err := os.Chmod(tmp.Name(), 0644); err != nil {
-		return err
-	}
-	return os.Rename(tmp.Name(), filename)
+	return normalizeMetricFamilies(metricFamiliesByName), errs.MaybeUnwrap()
 }
 
 // processMetric is an internal helper method only used by the Gather method.
@@ -582,20 +464,16 @@ func processMetric(
 	metric Metric,
 	metricFamiliesByName map[string]*dto.MetricFamily,
 	metricHashes map[uint64]struct{},
+	dimHashes map[string]uint64,
 	registeredDescIDs map[uint64]struct{},
 ) error {
 	desc := metric.Desc()
-	// Wrapped metrics collected by an unchecked Collector can have an
-	// invalid Desc.
-	if desc.err != nil {
-		return desc.err
-	}
 	dtoMetric := &dto.Metric{}
 	if err := metric.Write(dtoMetric); err != nil {
 		return fmt.Errorf("error collecting metric %v: %s", desc, err)
 	}
 	metricFamily, ok := metricFamiliesByName[desc.fqName]
-	if ok { // Existing name.
+	if ok {
 		if metricFamily.GetHelp() != desc.help {
 			return fmt.Errorf(
 				"collected metric %s %s has help %q but should have %q",
@@ -642,7 +520,7 @@ func processMetric(
 		default:
 			panic("encountered MetricFamily with invalid type")
 		}
-	} else { // New name.
+	} else {
 		metricFamily = &dto.MetricFamily{}
 		metricFamily.Name = proto.String(desc.fqName)
 		metricFamily.Help = proto.String(desc.help)
@@ -661,12 +539,9 @@ func processMetric(
 		default:
 			return fmt.Errorf("empty metric collected: %s", dtoMetric)
 		}
-		if err := checkSuffixCollisions(metricFamily, metricFamiliesByName); err != nil {
-			return err
-		}
 		metricFamiliesByName[desc.fqName] = metricFamily
 	}
-	if err := checkMetricConsistency(metricFamily, dtoMetric, metricHashes); err != nil {
+	if err := checkMetricConsistency(metricFamily, dtoMetric, metricHashes, dimHashes); err != nil {
 		return err
 	}
 	if registeredDescIDs != nil {
@@ -688,7 +563,7 @@ func processMetric(
 // Gatherers is a slice of Gatherer instances that implements the Gatherer
 // interface itself. Its Gather method calls Gather on all Gatherers in the
 // slice in order and returns the merged results. Errors returned from the
-// Gather calls are all returned in a flattened MultiError. Duplicate and
+// Gather calles are all returned in a flattened MultiError. Duplicate and
 // inconsistent Metrics are skipped (first occurrence in slice order wins) and
 // reported in the returned error.
 //
@@ -708,6 +583,7 @@ func (gs Gatherers) Gather() ([]*dto.MetricFamily, error) {
 	var (
 		metricFamiliesByName = map[string]*dto.MetricFamily{}
 		metricHashes         = map[uint64]struct{}{}
+		dimHashes            = map[string]uint64{}
 		errs                 MultiError // The collected errors to return in the end.
 	)
 
@@ -744,14 +620,10 @@ func (gs Gatherers) Gather() ([]*dto.MetricFamily, error) {
 				existingMF.Name = mf.Name
 				existingMF.Help = mf.Help
 				existingMF.Type = mf.Type
-				if err := checkSuffixCollisions(existingMF, metricFamiliesByName); err != nil {
-					errs = append(errs, err)
-					continue
-				}
 				metricFamiliesByName[mf.GetName()] = existingMF
 			}
 			for _, m := range mf.Metric {
-				if err := checkMetricConsistency(existingMF, m, metricHashes); err != nil {
+				if err := checkMetricConsistency(existingMF, m, metricHashes, dimHashes); err != nil {
 					errs = append(errs, err)
 					continue
 				}
@@ -759,80 +631,88 @@ func (gs Gatherers) Gather() ([]*dto.MetricFamily, error) {
 			}
 		}
 	}
-	return internal.NormalizeMetricFamilies(metricFamiliesByName), errs.MaybeUnwrap()
+	return normalizeMetricFamilies(metricFamiliesByName), errs.MaybeUnwrap()
 }
 
-// checkSuffixCollisions checks for collisions with the “magic” suffixes the
-// Prometheus text format and the internal metric representation of the
-// Prometheus server add while flattening Summaries and Histograms.
-func checkSuffixCollisions(mf *dto.MetricFamily, mfs map[string]*dto.MetricFamily) error {
-	var (
-		newName              = mf.GetName()
-		newType              = mf.GetType()
-		newNameWithoutSuffix = ""
-	)
-	switch {
-	case strings.HasSuffix(newName, "_count"):
-		newNameWithoutSuffix = newName[:len(newName)-6]
-	case strings.HasSuffix(newName, "_sum"):
-		newNameWithoutSuffix = newName[:len(newName)-4]
-	case strings.HasSuffix(newName, "_bucket"):
-		newNameWithoutSuffix = newName[:len(newName)-7]
+// metricSorter is a sortable slice of *dto.Metric.
+type metricSorter []*dto.Metric
+
+func (s metricSorter) Len() int {
+	return len(s)
+}
+
+func (s metricSorter) Swap(i, j int) {
+	s[i], s[j] = s[j], s[i]
+}
+
+func (s metricSorter) Less(i, j int) bool {
+	if len(s[i].Label) != len(s[j].Label) {
+		// This should not happen. The metrics are
+		// inconsistent. However, we have to deal with the fact, as
+		// people might use custom collectors or metric family injection
+		// to create inconsistent metrics. So let's simply compare the
+		// number of labels in this case. That will still yield
+		// reproducible sorting.
+		return len(s[i].Label) < len(s[j].Label)
 	}
-	if newNameWithoutSuffix != "" {
-		if existingMF, ok := mfs[newNameWithoutSuffix]; ok {
-			switch existingMF.GetType() {
-			case dto.MetricType_SUMMARY:
-				if !strings.HasSuffix(newName, "_bucket") {
-					return fmt.Errorf(
-						"collected metric named %q collides with previously collected summary named %q",
-						newName, newNameWithoutSuffix,
-					)
-				}
-			case dto.MetricType_HISTOGRAM:
-				return fmt.Errorf(
-					"collected metric named %q collides with previously collected histogram named %q",
-					newName, newNameWithoutSuffix,
-				)
-			}
+	for n, lp := range s[i].Label {
+		vi := lp.GetValue()
+		vj := s[j].Label[n].GetValue()
+		if vi != vj {
+			return vi < vj
 		}
 	}
-	if newType == dto.MetricType_SUMMARY || newType == dto.MetricType_HISTOGRAM {
-		if _, ok := mfs[newName+"_count"]; ok {
-			return fmt.Errorf(
-				"collected histogram or summary named %q collides with previously collected metric named %q",
-				newName, newName+"_count",
-			)
-		}
-		if _, ok := mfs[newName+"_sum"]; ok {
-			return fmt.Errorf(
-				"collected histogram or summary named %q collides with previously collected metric named %q",
-				newName, newName+"_sum",
-			)
+
+	// We should never arrive here. Multiple metrics with the same
+	// label set in the same scrape will lead to undefined ingestion
+	// behavior. However, as above, we have to provide stable sorting
+	// here, even for inconsistent metrics. So sort equal metrics
+	// by their timestamp, with missing timestamps (implying "now")
+	// coming last.
+	if s[i].TimestampMs == nil {
+		return false
+	}
+	if s[j].TimestampMs == nil {
+		return true
+	}
+	return s[i].GetTimestampMs() < s[j].GetTimestampMs()
+}
+
+// normalizeMetricFamilies returns a MetricFamily slice with empty
+// MetricFamilies pruned and the remaining MetricFamilies sorted by name within
+// the slice, with the contained Metrics sorted within each MetricFamily.
+func normalizeMetricFamilies(metricFamiliesByName map[string]*dto.MetricFamily) []*dto.MetricFamily {
+	for _, mf := range metricFamiliesByName {
+		sort.Sort(metricSorter(mf.Metric))
+	}
+	names := make([]string, 0, len(metricFamiliesByName))
+	for name, mf := range metricFamiliesByName {
+		if len(mf.Metric) > 0 {
+			names = append(names, name)
 		}
 	}
-	if newType == dto.MetricType_HISTOGRAM {
-		if _, ok := mfs[newName+"_bucket"]; ok {
-			return fmt.Errorf(
-				"collected histogram named %q collides with previously collected metric named %q",
-				newName, newName+"_bucket",
-			)
-		}
+	sort.Strings(names)
+	result := make([]*dto.MetricFamily, 0, len(names))
+	for _, name := range names {
+		result = append(result, metricFamiliesByName[name])
 	}
-	return nil
+	return result
 }
 
 // checkMetricConsistency checks if the provided Metric is consistent with the
-// provided MetricFamily. It also hashes the Metric labels and the MetricFamily
+// provided MetricFamily. It also hashed the Metric labels and the MetricFamily
 // name. If the resulting hash is already in the provided metricHashes, an error
-// is returned. If not, it is added to metricHashes.
+// is returned. If not, it is added to metricHashes. The provided dimHashes maps
+// MetricFamily names to their dimHash (hashed sorted label names). If dimHashes
+// doesn't yet contain a hash for the provided MetricFamily, it is
+// added. Otherwise, an error is returned if the existing dimHashes in not equal
+// the calculated dimHash.
 func checkMetricConsistency(
 	metricFamily *dto.MetricFamily,
 	dtoMetric *dto.Metric,
 	metricHashes map[uint64]struct{},
+	dimHashes map[string]uint64,
 ) error {
-	name := metricFamily.GetName()
-
 	// Type consistency with metric family.
 	if metricFamily.GetType() == dto.MetricType_GAUGE && dtoMetric.Gauge == nil ||
 		metricFamily.GetType() == dto.MetricType_COUNTER && dtoMetric.Counter == nil ||
@@ -840,65 +720,47 @@ func checkMetricConsistency(
 		metricFamily.GetType() == dto.MetricType_HISTOGRAM && dtoMetric.Histogram == nil ||
 		metricFamily.GetType() == dto.MetricType_UNTYPED && dtoMetric.Untyped == nil {
 		return fmt.Errorf(
-			"collected metric %q { %s} is not a %s",
-			name, dtoMetric, metricFamily.GetType(),
+			"collected metric %s %s is not a %s",
+			metricFamily.GetName(), dtoMetric, metricFamily.GetType(),
 		)
 	}
 
-	previousLabelName := ""
 	for _, labelPair := range dtoMetric.GetLabel() {
-		labelName := labelPair.GetName()
-		if labelName == previousLabelName {
-			return fmt.Errorf(
-				"collected metric %q { %s} has two or more labels with the same name: %s",
-				name, dtoMetric, labelName,
-			)
+		if !utf8.ValidString(*labelPair.Value) {
+			return fmt.Errorf("collected metric's label %s is not utf8: %#v", *labelPair.Name, *labelPair.Value)
 		}
-		if !checkLabelName(labelName) {
-			return fmt.Errorf(
-				"collected metric %q { %s} has a label with an invalid name: %s",
-				name, dtoMetric, labelName,
-			)
-		}
-		if dtoMetric.Summary != nil && labelName == quantileLabel {
-			return fmt.Errorf(
-				"collected metric %q { %s} must not have an explicit %q label",
-				name, dtoMetric, quantileLabel,
-			)
-		}
-		if !utf8.ValidString(labelPair.GetValue()) {
-			return fmt.Errorf(
-				"collected metric %q { %s} has a label named %q whose value is not utf8: %#v",
-				name, dtoMetric, labelName, labelPair.GetValue())
-		}
-		previousLabelName = labelName
 	}
 
-	// Is the metric unique (i.e. no other metric with the same name and the same labels)?
+	// Is the metric unique (i.e. no other metric with the same name and the same label values)?
 	h := hashNew()
-	h = hashAdd(h, name)
+	h = hashAdd(h, metricFamily.GetName())
 	h = hashAddByte(h, separatorByte)
+	dh := hashNew()
 	// Make sure label pairs are sorted. We depend on it for the consistency
 	// check.
-	if !sort.IsSorted(labelPairSorter(dtoMetric.Label)) {
-		// We cannot sort dtoMetric.Label in place as it is immutable by contract.
-		copiedLabels := make([]*dto.LabelPair, len(dtoMetric.Label))
-		copy(copiedLabels, dtoMetric.Label)
-		sort.Sort(labelPairSorter(copiedLabels))
-		dtoMetric.Label = copiedLabels
-	}
+	sort.Sort(LabelPairSorter(dtoMetric.Label))
 	for _, lp := range dtoMetric.Label {
-		h = hashAdd(h, lp.GetName())
-		h = hashAddByte(h, separatorByte)
 		h = hashAdd(h, lp.GetValue())
 		h = hashAddByte(h, separatorByte)
+		dh = hashAdd(dh, lp.GetName())
+		dh = hashAddByte(dh, separatorByte)
 	}
 	if _, exists := metricHashes[h]; exists {
 		return fmt.Errorf(
-			"collected metric %q { %s} was collected before with the same name and label values",
-			name, dtoMetric,
+			"collected metric %s %s was collected before with the same name and label values",
+			metricFamily.GetName(), dtoMetric,
 		)
 	}
+	if dimHash, ok := dimHashes[metricFamily.GetName()]; ok {
+		if dimHash != dh {
+			return fmt.Errorf(
+				"collected metric %s %s has label dimensions inconsistent with previously collected metrics in the same metric family",
+				metricFamily.GetName(), dtoMetric,
+			)
+		}
+	} else {
+		dimHashes[metricFamily.GetName()] = dh
+	}
 	metricHashes[h] = struct{}{}
 	return nil
 }
@@ -917,8 +779,8 @@ func checkDescConsistency(
 	}
 
 	// Is the desc consistent with the content of the metric?
-	lpsFromDesc := make([]*dto.LabelPair, len(desc.constLabelPairs), len(dtoMetric.Label))
-	copy(lpsFromDesc, desc.constLabelPairs)
+	lpsFromDesc := make([]*dto.LabelPair, 0, len(dtoMetric.Label))
+	lpsFromDesc = append(lpsFromDesc, desc.constLabelPairs...)
 	for _, l := range desc.variableLabels {
 		lpsFromDesc = append(lpsFromDesc, &dto.LabelPair{
 			Name: proto.String(l),
@@ -930,7 +792,7 @@ func checkDescConsistency(
 			metricFamily.GetName(), dtoMetric, desc,
 		)
 	}
-	sort.Sort(labelPairSorter(lpsFromDesc))
+	sort.Sort(LabelPairSorter(lpsFromDesc))
 	for i, lpFromDesc := range lpsFromDesc {
 		lpFromMetric := dtoMetric.Label[i]
 		if lpFromDesc.GetName() != lpFromMetric.GetName() ||

vendor/github.com/prometheus/client_golang/prometheus/summary.go

@@ -16,10 +16,8 @@ package prometheus
 import (
 	"fmt"
 	"math"
-	"runtime"
 	"sort"
 	"sync"
-	"sync/atomic"
 	"time"
 
 	"github.com/beorn7/perks/quantile"
@@ -39,7 +37,7 @@ const quantileLabel = "quantile"
 // A typical use-case is the observation of request latencies. By default, a
 // Summary provides the median, the 90th and the 99th percentile of the latency
 // as rank estimations. However, the default behavior will change in the
-// upcoming v1.0.0 of the library. There will be no rank estimations at all by
+// upcoming v0.10 of the library. There will be no rank estiamtions at all by
 // default. For a sane transition, it is recommended to set the desired rank
 // estimations explicitly.
 //
@@ -58,8 +56,16 @@ type Summary interface {
 	Observe(float64)
 }
 
-var errQuantileLabelNotAllowed = fmt.Errorf(
-	"%q is not allowed as label name in summaries", quantileLabel,
+// DefObjectives are the default Summary quantile values.
+//
+// Deprecated: DefObjectives will not be used as the default objectives in
+// v0.10 of the library. The default Summary will have no quantiles then.
+var (
+	DefObjectives = map[float64]float64{0.5: 0.05, 0.9: 0.01, 0.99: 0.001}
+
+	errQuantileLabelNotAllowed = fmt.Errorf(
+		"%q is not allowed as label name in summaries", quantileLabel,
+	)
 )
 
 // Default values for SummaryOpts.
@@ -75,10 +81,10 @@ const (
 )
 
 // SummaryOpts bundles the options for creating a Summary metric. It is
-// mandatory to set Name to a non-empty string. While all other fields are
-// optional and can safely be left at their zero value, it is recommended to set
-// a help string and to explicitly set the Objectives field to the desired value
-// as the default value will change in the upcoming v1.0.0 of the library.
+// mandatory to set Name and Help to a non-empty string. While all other fields
+// are optional and can safely be left at their zero value, it is recommended to
+// explicitly set the Objectives field to the desired value as the default value
+// will change in the upcoming v0.10 of the library.
 type SummaryOpts struct {
 	// Namespace, Subsystem, and Name are components of the fully-qualified
 	// name of the Summary (created by joining these components with
@@ -89,7 +95,7 @@ type SummaryOpts struct {
 	Subsystem string
 	Name      string
 
-	// Help provides information about this Summary.
+	// Help provides information about this Summary. Mandatory!
 	//
 	// Metrics with the same fully-qualified name must have the same Help
 	// string.
@@ -99,11 +105,6 @@ type SummaryOpts struct {
 	// with the same fully-qualified name must have the same label names in
 	// their ConstLabels.
 	//
-	// Due to the way a Summary is represented in the Prometheus text format
-	// and how it is handled by the Prometheus server internally, “quantile”
-	// is an illegal label name. Construction of a Summary or SummaryVec
-	// will panic if this label name is used in ConstLabels.
-	//
 	// ConstLabels are only used rarely. In particular, do not use them to
 	// attach the same labels to all your metrics. Those use cases are
 	// better covered by target labels set by the scraping Prometheus
@@ -115,8 +116,13 @@ type SummaryOpts struct {
 	// Objectives defines the quantile rank estimates with their respective
 	// absolute error. If Objectives[q] = e, then the value reported for q
 	// will be the φ-quantile value for some φ between q-e and q+e.  The
-	// default value is an empty map, resulting in a summary without
-	// quantiles.
+	// default value is DefObjectives. It is used if Objectives is left at
+	// its zero value (i.e. nil). To create a Summary without Objectives,
+	// set it to an empty map (i.e. map[float64]float64{}).
+	//
+	// Deprecated: Note that the current value of DefObjectives is
+	// deprecated. It will be replaced by an empty map in v0.10 of the
+	// library. Please explicitly set Objectives to the desired value.
 	Objectives map[float64]float64
 
 	// MaxAge defines the duration for which an observation stays relevant
@@ -140,7 +146,7 @@ type SummaryOpts struct {
 	BufCap uint32
 }
 
-// Problem with the sliding-window decay algorithm... The Merge method of
+// Great fuck-up with the sliding-window decay algorithm... The Merge method of
 // perk/quantile is actually not working as advertised - and it might be
 // unfixable, as the underlying algorithm is apparently not capable of merging
 // summaries in the first place. To avoid using Merge, we are currently adding
@@ -170,7 +176,7 @@ func NewSummary(opts SummaryOpts) Summary {
 
 func newSummary(desc *Desc, opts SummaryOpts, labelValues ...string) Summary {
 	if len(desc.variableLabels) != len(labelValues) {
-		panic(makeInconsistentCardinalityError(desc.fqName, desc.variableLabels, labelValues))
+		panic(errInconsistentCardinality)
 	}
 
 	for _, n := range desc.variableLabels {
@@ -185,7 +191,7 @@ func newSummary(desc *Desc, opts SummaryOpts, labelValues ...string) Summary {
 	}
 
 	if opts.Objectives == nil {
-		opts.Objectives = map[float64]float64{}
+		opts.Objectives = DefObjectives
 	}
 
 	if opts.MaxAge < 0 {
@@ -203,17 +209,6 @@ func newSummary(desc *Desc, opts SummaryOpts, labelValues ...string) Summary {
 		opts.BufCap = DefBufCap
 	}
 
-	if len(opts.Objectives) == 0 {
-		// Use the lock-free implementation of a Summary without objectives.
-		s := &noObjectivesSummary{
-			desc:       desc,
-			labelPairs: makeLabelPairs(desc, labelValues),
-			counts:     [2]*summaryCounts{&summaryCounts{}, &summaryCounts{}},
-		}
-		s.init(s) // Init self-collection.
-		return s
-	}
-
 	s := &summary{
 		desc: desc,
 
@@ -382,116 +377,6 @@ func (s *summary) swapBufs(now time.Time) {
 	}
 }
 
-type summaryCounts struct {
-	// sumBits contains the bits of the float64 representing the sum of all
-	// observations. sumBits and count have to go first in the struct to
-	// guarantee alignment for atomic operations.
-	// http://golang.org/pkg/sync/atomic/#pkg-note-BUG
-	sumBits uint64
-	count   uint64
-}
-
-type noObjectivesSummary struct {
-	// countAndHotIdx enables lock-free writes with use of atomic updates.
-	// The most significant bit is the hot index [0 or 1] of the count field
-	// below. Observe calls update the hot one. All remaining bits count the
-	// number of Observe calls. Observe starts by incrementing this counter,
-	// and finish by incrementing the count field in the respective
-	// summaryCounts, as a marker for completion.
-	//
-	// Calls of the Write method (which are non-mutating reads from the
-	// perspective of the summary) swap the hot–cold under the writeMtx
-	// lock. A cooldown is awaited (while locked) by comparing the number of
-	// observations with the initiation count. Once they match, then the
-	// last observation on the now cool one has completed. All cool fields must
-	// be merged into the new hot before releasing writeMtx.
-
-	// Fields with atomic access first! See alignment constraint:
-	// http://golang.org/pkg/sync/atomic/#pkg-note-BUG
-	countAndHotIdx uint64
-
-	selfCollector
-	desc     *Desc
-	writeMtx sync.Mutex // Only used in the Write method.
-
-	// Two counts, one is "hot" for lock-free observations, the other is
-	// "cold" for writing out a dto.Metric. It has to be an array of
-	// pointers to guarantee 64bit alignment of the histogramCounts, see
-	// http://golang.org/pkg/sync/atomic/#pkg-note-BUG.
-	counts [2]*summaryCounts
-
-	labelPairs []*dto.LabelPair
-}
-
-func (s *noObjectivesSummary) Desc() *Desc {
-	return s.desc
-}
-
-func (s *noObjectivesSummary) Observe(v float64) {
-	// We increment h.countAndHotIdx so that the counter in the lower
-	// 63 bits gets incremented. At the same time, we get the new value
-	// back, which we can use to find the currently-hot counts.
-	n := atomic.AddUint64(&s.countAndHotIdx, 1)
-	hotCounts := s.counts[n>>63]
-
-	for {
-		oldBits := atomic.LoadUint64(&hotCounts.sumBits)
-		newBits := math.Float64bits(math.Float64frombits(oldBits) + v)
-		if atomic.CompareAndSwapUint64(&hotCounts.sumBits, oldBits, newBits) {
-			break
-		}
-	}
-	// Increment count last as we take it as a signal that the observation
-	// is complete.
-	atomic.AddUint64(&hotCounts.count, 1)
-}
-
-func (s *noObjectivesSummary) Write(out *dto.Metric) error {
-	// For simplicity, we protect this whole method by a mutex. It is not in
-	// the hot path, i.e. Observe is called much more often than Write. The
-	// complication of making Write lock-free isn't worth it, if possible at
-	// all.
-	s.writeMtx.Lock()
-	defer s.writeMtx.Unlock()
-
-	// Adding 1<<63 switches the hot index (from 0 to 1 or from 1 to 0)
-	// without touching the count bits. See the struct comments for a full
-	// description of the algorithm.
-	n := atomic.AddUint64(&s.countAndHotIdx, 1<<63)
-	// count is contained unchanged in the lower 63 bits.
-	count := n & ((1 << 63) - 1)
-	// The most significant bit tells us which counts is hot. The complement
-	// is thus the cold one.
-	hotCounts := s.counts[n>>63]
-	coldCounts := s.counts[(^n)>>63]
-
-	// Await cooldown.
-	for count != atomic.LoadUint64(&coldCounts.count) {
-		runtime.Gosched() // Let observations get work done.
-	}
-
-	sum := &dto.Summary{
-		SampleCount: proto.Uint64(count),
-		SampleSum:   proto.Float64(math.Float64frombits(atomic.LoadUint64(&coldCounts.sumBits))),
-	}
-
-	out.Summary = sum
-	out.Label = s.labelPairs
-
-	// Finally add all the cold counts to the new hot counts and reset the cold counts.
-	atomic.AddUint64(&hotCounts.count, count)
-	atomic.StoreUint64(&coldCounts.count, 0)
-	for {
-		oldBits := atomic.LoadUint64(&hotCounts.sumBits)
-		newBits := math.Float64bits(math.Float64frombits(oldBits) + sum.GetSampleSum())
-		if atomic.CompareAndSwapUint64(&hotCounts.sumBits, oldBits, newBits) {
-			atomic.StoreUint64(&coldCounts.sumBits, 0)
-			break
-		}
-	}
-	return nil
-}
-
 type quantSort []*dto.Quantile
 
 func (s quantSort) Len() int {
@@ -517,16 +402,7 @@ type SummaryVec struct {
 
 // NewSummaryVec creates a new SummaryVec based on the provided SummaryOpts and
 // partitioned by the given label names.
-//
-// Due to the way a Summary is represented in the Prometheus text format and how
-// it is handled by the Prometheus server internally, “quantile” is an illegal
-// label name. NewSummaryVec will panic if this label name is used.
 func NewSummaryVec(opts SummaryOpts, labelNames []string) *SummaryVec {
-	for _, ln := range labelNames {
-		if ln == quantileLabel {
-			panic(errQuantileLabelNotAllowed)
-		}
-	}
 	desc := NewDesc(
 		BuildFQName(opts.Namespace, opts.Subsystem, opts.Name),
 		opts.Help,
@@ -696,7 +572,7 @@ func (s *constSummary) Write(out *dto.Metric) error {
 //     map[float64]float64{0.5: 0.23, 0.99: 0.56}
 //
 // NewConstSummary returns an error if the length of labelValues is not
-// consistent with the variable labels in Desc or if Desc is invalid.
+// consistent with the variable labels in Desc.
 func NewConstSummary(
 	desc *Desc,
 	count uint64,
@@ -704,9 +580,6 @@ func NewConstSummary(
 	quantiles map[float64]float64,
 	labelValues ...string,
 ) (Metric, error) {
-	if desc.err != nil {
-		return nil, desc.err
-	}
 	if err := validateLabelValues(labelValues, len(desc.variableLabels)); err != nil {
 		return nil, err
 	}

vendor/github.com/prometheus/client_golang/prometheus/timer.go

@@ -39,16 +39,13 @@ func NewTimer(o Observer) *Timer {
 
 // ObserveDuration records the duration passed since the Timer was created with
 // NewTimer. It calls the Observe method of the Observer provided during
-// construction with the duration in seconds as an argument. The observed
-// duration is also returned. ObserveDuration is usually called with a defer
-// statement.
+// construction with the duration in seconds as an argument. ObserveDuration is
+// usually called with a defer statement.
 //
 // Note that this method is only guaranteed to never observe negative durations
 // if used with Go1.9+.
-func (t *Timer) ObserveDuration() time.Duration {
-	d := time.Since(t.begin)
+func (t *Timer) ObserveDuration() {
 	if t.observer != nil {
-		t.observer.Observe(d.Seconds())
+		t.observer.Observe(time.Since(t.begin).Seconds())
 	}
-	return d
 }

vendor/github.com/prometheus/client_golang/prometheus/value.go

@@ -17,9 +17,9 @@ import (
 	"fmt"
 	"sort"
 
-	"github.com/golang/protobuf/proto"
-
 	dto "github.com/prometheus/client_model/go"
+
+	"github.com/golang/protobuf/proto"
 )
 
 // ValueType is an enumeration of metric types that represent a simple value.
@@ -77,12 +77,8 @@ func (v *valueFunc) Write(out *dto.Metric) error {
 // operations. However, when implementing custom Collectors, it is useful as a
 // throw-away metric that is generated on the fly to send it to Prometheus in
 // the Collect method. NewConstMetric returns an error if the length of
-// labelValues is not consistent with the variable labels in Desc or if Desc is
-// invalid.
+// labelValues is not consistent with the variable labels in Desc.
 func NewConstMetric(desc *Desc, valueType ValueType, value float64, labelValues ...string) (Metric, error) {
-	if desc.err != nil {
-		return nil, desc.err
-	}
 	if err := validateLabelValues(labelValues, len(desc.variableLabels)); err != nil {
 		return nil, err
 	}
@@ -156,7 +152,9 @@ func makeLabelPairs(desc *Desc, labelValues []string) []*dto.LabelPair {
 			Value: proto.String(labelValues[i]),
 		})
 	}
-	labelPairs = append(labelPairs, desc.constLabelPairs...)
-	sort.Sort(labelPairSorter(labelPairs))
+	for _, lp := range desc.constLabelPairs {
+		labelPairs = append(labelPairs, lp)
+	}
+	sort.Sort(LabelPairSorter(labelPairs))
 	return labelPairs
 }

vendor/github.com/prometheus/client_golang/prometheus/vec.go

@@ -277,9 +277,6 @@ func (m *metricMap) deleteByHashWithLabelValues(
 func (m *metricMap) deleteByHashWithLabels(
 	h uint64, labels Labels, curry []curriedLabelValue,
 ) bool {
-	m.mtx.Lock()
-	defer m.mtx.Unlock()
-
 	metrics, ok := m.metrics[h]
 	if !ok {
 		return false

vendor/github.com/prometheus/client_golang/prometheus/wrap.go

@@ -1,200 +0,0 @@
-// Copyright 2018 The Prometheus Authors
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-// http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-package prometheus
-
-import (
-	"fmt"
-	"sort"
-
-	"github.com/golang/protobuf/proto"
-
-	dto "github.com/prometheus/client_model/go"
-)
-
-// WrapRegistererWith returns a Registerer wrapping the provided
-// Registerer. Collectors registered with the returned Registerer will be
-// registered with the wrapped Registerer in a modified way. The modified
-// Collector adds the provided Labels to all Metrics it collects (as
-// ConstLabels). The Metrics collected by the unmodified Collector must not
-// duplicate any of those labels.
-//
-// WrapRegistererWith provides a way to add fixed labels to a subset of
-// Collectors. It should not be used to add fixed labels to all metrics exposed.
-//
-// Conflicts between Collectors registered through the original Registerer with
-// Collectors registered through the wrapping Registerer will still be
-// detected. Any AlreadyRegisteredError returned by the Register method of
-// either Registerer will contain the ExistingCollector in the form it was
-// provided to the respective registry.
-//
-// The Collector example demonstrates a use of WrapRegistererWith.
-func WrapRegistererWith(labels Labels, reg Registerer) Registerer {
-	return &wrappingRegisterer{
-		wrappedRegisterer: reg,
-		labels:            labels,
-	}
-}
-
-// WrapRegistererWithPrefix returns a Registerer wrapping the provided
-// Registerer. Collectors registered with the returned Registerer will be
-// registered with the wrapped Registerer in a modified way. The modified
-// Collector adds the provided prefix to the name of all Metrics it collects.
-//
-// WrapRegistererWithPrefix is useful to have one place to prefix all metrics of
-// a sub-system. To make this work, register metrics of the sub-system with the
-// wrapping Registerer returned by WrapRegistererWithPrefix. It is rarely useful
-// to use the same prefix for all metrics exposed. In particular, do not prefix
-// metric names that are standardized across applications, as that would break
-// horizontal monitoring, for example the metrics provided by the Go collector
-// (see NewGoCollector) and the process collector (see NewProcessCollector). (In
-// fact, those metrics are already prefixed with “go_” or “process_”,
-// respectively.)
-//
-// Conflicts between Collectors registered through the original Registerer with
-// Collectors registered through the wrapping Registerer will still be
-// detected. Any AlreadyRegisteredError returned by the Register method of
-// either Registerer will contain the ExistingCollector in the form it was
-// provided to the respective registry.
-func WrapRegistererWithPrefix(prefix string, reg Registerer) Registerer {
-	return &wrappingRegisterer{
-		wrappedRegisterer: reg,
-		prefix:            prefix,
-	}
-}
-
-type wrappingRegisterer struct {
-	wrappedRegisterer Registerer
-	prefix            string
-	labels            Labels
-}
-
-func (r *wrappingRegisterer) Register(c Collector) error {
-	return r.wrappedRegisterer.Register(&wrappingCollector{
-		wrappedCollector: c,
-		prefix:           r.prefix,
-		labels:           r.labels,
-	})
-}
-
-func (r *wrappingRegisterer) MustRegister(cs ...Collector) {
-	for _, c := range cs {
-		if err := r.Register(c); err != nil {
-			panic(err)
-		}
-	}
-}
-
-func (r *wrappingRegisterer) Unregister(c Collector) bool {
-	return r.wrappedRegisterer.Unregister(&wrappingCollector{
-		wrappedCollector: c,
-		prefix:           r.prefix,
-		labels:           r.labels,
-	})
-}
-
-type wrappingCollector struct {
-	wrappedCollector Collector
-	prefix           string
-	labels           Labels
-}
-
-func (c *wrappingCollector) Collect(ch chan<- Metric) {
-	wrappedCh := make(chan Metric)
-	go func() {
-		c.wrappedCollector.Collect(wrappedCh)
-		close(wrappedCh)
-	}()
-	for m := range wrappedCh {
-		ch <- &wrappingMetric{
-			wrappedMetric: m,
-			prefix:        c.prefix,
-			labels:        c.labels,
-		}
-	}
-}
-
-func (c *wrappingCollector) Describe(ch chan<- *Desc) {
-	wrappedCh := make(chan *Desc)
-	go func() {
-		c.wrappedCollector.Describe(wrappedCh)
-		close(wrappedCh)
-	}()
-	for desc := range wrappedCh {
-		ch <- wrapDesc(desc, c.prefix, c.labels)
-	}
-}
-
-func (c *wrappingCollector) unwrapRecursively() Collector {
-	switch wc := c.wrappedCollector.(type) {
-	case *wrappingCollector:
-		return wc.unwrapRecursively()
-	default:
-		return wc
-	}
-}
-
-type wrappingMetric struct {
-	wrappedMetric Metric
-	prefix        string
-	labels        Labels
-}
-
-func (m *wrappingMetric) Desc() *Desc {
-	return wrapDesc(m.wrappedMetric.Desc(), m.prefix, m.labels)
-}
-
-func (m *wrappingMetric) Write(out *dto.Metric) error {
-	if err := m.wrappedMetric.Write(out); err != nil {
-		return err
-	}
-	if len(m.labels) == 0 {
-		// No wrapping labels.
-		return nil
-	}
-	for ln, lv := range m.labels {
-		out.Label = append(out.Label, &dto.LabelPair{
-			Name:  proto.String(ln),
-			Value: proto.String(lv),
-		})
-	}
-	sort.Sort(labelPairSorter(out.Label))
-	return nil
-}
-
-func wrapDesc(desc *Desc, prefix string, labels Labels) *Desc {
-	constLabels := Labels{}
-	for _, lp := range desc.constLabelPairs {
-		constLabels[*lp.Name] = *lp.Value
-	}
-	for ln, lv := range labels {
-		if _, alreadyUsed := constLabels[ln]; alreadyUsed {
-			return &Desc{
-				fqName:          desc.fqName,
-				help:            desc.help,
-				variableLabels:  desc.variableLabels,
-				constLabelPairs: desc.constLabelPairs,
-				err:             fmt.Errorf("attempted wrapping with already existing label name %q", ln),
-			}
-		}
-		constLabels[ln] = lv
-	}
-	// NewDesc will do remaining validations.
-	newDesc := NewDesc(prefix+desc.fqName, desc.help, desc.variableLabels, constLabels)
-	// Propagate errors if there was any. This will override any errer
-	// created by NewDesc above, i.e. earlier errors get precedence.
-	if desc.err != nil {
-		newDesc.err = desc.err
-	}
-	return newDesc
-}

vendor/github.com/prometheus/common/expfmt/text_create.go

@@ -14,45 +14,13 @@
 package expfmt
 
 import (
-	"bytes"
 	"fmt"
 	"io"
 	"math"
-	"strconv"
 	"strings"
-	"sync"
-
-	"github.com/prometheus/common/model"
 
 	dto "github.com/prometheus/client_model/go"
-)
-
-// enhancedWriter has all the enhanced write functions needed here. bytes.Buffer
-// implements it.
-type enhancedWriter interface {
-	io.Writer
-	WriteRune(r rune) (n int, err error)
-	WriteString(s string) (n int, err error)
-	WriteByte(c byte) error
-}
-
-const (
-	initialBufSize    = 512
-	initialNumBufSize = 24
-)
-
-var (
-	bufPool = sync.Pool{
-		New: func() interface{} {
-			return bytes.NewBuffer(make([]byte, 0, initialBufSize))
-		},
-	}
-	numBufPool = sync.Pool{
-		New: func() interface{} {
-			b := make([]byte, 0, initialNumBufSize)
-			return &b
-		},
-	}
+	"github.com/prometheus/common/model"
 )
 
 // MetricFamilyToText converts a MetricFamily proto message into text format and
@@ -64,92 +32,37 @@ var (
 // will result in invalid text format output.
 //
 // This method fulfills the type 'prometheus.encoder'.
-func MetricFamilyToText(out io.Writer, in *dto.MetricFamily) (written int, err error) {
+func MetricFamilyToText(out io.Writer, in *dto.MetricFamily) (int, error) {
+	var written int
+
 	// Fail-fast checks.
 	if len(in.Metric) == 0 {
-		return 0, fmt.Errorf("MetricFamily has no metrics: %s", in)
+		return written, fmt.Errorf("MetricFamily has no metrics: %s", in)
 	}
 	name := in.GetName()
 	if name == "" {
-		return 0, fmt.Errorf("MetricFamily has no name: %s", in)
+		return written, fmt.Errorf("MetricFamily has no name: %s", in)
 	}
 
-	// Try the interface upgrade. If it doesn't work, we'll use a
-	// bytes.Buffer from the sync.Pool and write out its content to out in a
-	// single go in the end.
-	w, ok := out.(enhancedWriter)
-	if !ok {
-		b := bufPool.Get().(*bytes.Buffer)
-		b.Reset()
-		w = b
-		defer func() {
-			bWritten, bErr := out.Write(b.Bytes())
-			written = bWritten
-			if err == nil {
-				err = bErr
-			}
-			bufPool.Put(b)
-		}()
-	}
-
-	var n int
-
 	// Comments, first HELP, then TYPE.
 	if in.Help != nil {
-		n, err = w.WriteString("# HELP ")
+		n, err := fmt.Fprintf(
+			out, "# HELP %s %s\n",
+			name, escapeString(*in.Help, false),
+		)
 		written += n
 		if err != nil {
-			return
+			return written, err
 		}
-		n, err = w.WriteString(name)
-		written += n
-		if err != nil {
-			return
-		}
-		err = w.WriteByte(' ')
-		written++
-		if err != nil {
-			return
-		}
-		n, err = writeEscapedString(w, *in.Help, false)
-		written += n
-		if err != nil {
-			return
-		}
-		err = w.WriteByte('\n')
-		written++
-		if err != nil {
-			return
-		}
-	}
-	n, err = w.WriteString("# TYPE ")
-	written += n
-	if err != nil {
-		return
-	}
-	n, err = w.WriteString(name)
-	written += n
-	if err != nil {
-		return
 	}
 	metricType := in.GetType()
-	switch metricType {
-	case dto.MetricType_COUNTER:
-		n, err = w.WriteString(" counter\n")
-	case dto.MetricType_GAUGE:
-		n, err = w.WriteString(" gauge\n")
-	case dto.MetricType_SUMMARY:
-		n, err = w.WriteString(" summary\n")
-	case dto.MetricType_UNTYPED:
-		n, err = w.WriteString(" untyped\n")
-	case dto.MetricType_HISTOGRAM:
-		n, err = w.WriteString(" histogram\n")
-	default:
-		return written, fmt.Errorf("unknown metric type %s", metricType.String())
-	}
+	n, err := fmt.Fprintf(
+		out, "# TYPE %s %s\n",
+		name, strings.ToLower(metricType.String()),
+	)
 	written += n
 	if err != nil {
-		return
+		return written, err
 	}
 
 	// Finally the samples, one line for each.
@@ -162,8 +75,9 @@ func MetricFamilyToText(out io.Writer, in *dto.MetricFamily) (written int, err e
 				)
 			}
 			n, err = writeSample(
-				w, name, "", metric, "", 0,
+				name, metric, "", "",
 				metric.Counter.GetValue(),
+				out,
 			)
 		case dto.MetricType_GAUGE:
 			if metric.Gauge == nil {
@@ -172,8 +86,9 @@ func MetricFamilyToText(out io.Writer, in *dto.MetricFamily) (written int, err e
 				)
 			}
 			n, err = writeSample(
-				w, name, "", metric, "", 0,
+				name, metric, "", "",
 				metric.Gauge.GetValue(),
+				out,
 			)
 		case dto.MetricType_UNTYPED:
 			if metric.Untyped == nil {
@@ -182,8 +97,9 @@ func MetricFamilyToText(out io.Writer, in *dto.MetricFamily) (written int, err e
 				)
 			}
 			n, err = writeSample(
-				w, name, "", metric, "", 0,
+				name, metric, "", "",
 				metric.Untyped.GetValue(),
+				out,
 			)
 		case dto.MetricType_SUMMARY:
 			if metric.Summary == nil {
@@ -193,26 +109,29 @@ func MetricFamilyToText(out io.Writer, in *dto.MetricFamily) (written int, err e
 			}
 			for _, q := range metric.Summary.Quantile {
 				n, err = writeSample(
-					w, name, "", metric,
-					model.QuantileLabel, q.GetQuantile(),
+					name, metric,
+					model.QuantileLabel, fmt.Sprint(q.GetQuantile()),
 					q.GetValue(),
+					out,
 				)
 				written += n
 				if err != nil {
-					return
+					return written, err
 				}
 			}
 			n, err = writeSample(
-				w, name, "_sum", metric, "", 0,
+				name+"_sum", metric, "", "",
 				metric.Summary.GetSampleSum(),
+				out,
 			)
-			written += n
 			if err != nil {
-				return
+				return written, err
 			}
+			written += n
 			n, err = writeSample(
-				w, name, "_count", metric, "", 0,
+				name+"_count", metric, "", "",
 				float64(metric.Summary.GetSampleCount()),
+				out,
 			)
 		case dto.MetricType_HISTOGRAM:
 			if metric.Histogram == nil {
@@ -221,42 +140,46 @@ func MetricFamilyToText(out io.Writer, in *dto.MetricFamily) (written int, err e
 				)
 			}
 			infSeen := false
-			for _, b := range metric.Histogram.Bucket {
+			for _, q := range metric.Histogram.Bucket {
 				n, err = writeSample(
-					w, name, "_bucket", metric,
-					model.BucketLabel, b.GetUpperBound(),
-					float64(b.GetCumulativeCount()),
+					name+"_bucket", metric,
+					model.BucketLabel, fmt.Sprint(q.GetUpperBound()),
+					float64(q.GetCumulativeCount()),
+					out,
 				)
 				written += n
 				if err != nil {
-					return
+					return written, err
 				}
-				if math.IsInf(b.GetUpperBound(), +1) {
+				if math.IsInf(q.GetUpperBound(), +1) {
 					infSeen = true
 				}
 			}
 			if !infSeen {
 				n, err = writeSample(
-					w, name, "_bucket", metric,
-					model.BucketLabel, math.Inf(+1),
+					name+"_bucket", metric,
+					model.BucketLabel, "+Inf",
 					float64(metric.Histogram.GetSampleCount()),
+					out,
 				)
-				written += n
 				if err != nil {
-					return
+					return written, err
 				}
+				written += n
 			}
 			n, err = writeSample(
-				w, name, "_sum", metric, "", 0,
+				name+"_sum", metric, "", "",
 				metric.Histogram.GetSampleSum(),
+				out,
 			)
-			written += n
 			if err != nil {
-				return
+				return written, err
 			}
+			written += n
 			n, err = writeSample(
-				w, name, "_count", metric, "", 0,
+				name+"_count", metric, "", "",
 				float64(metric.Histogram.GetSampleCount()),
+				out,
 			)
 		default:
 			return written, fmt.Errorf(
@@ -265,204 +188,116 @@ func MetricFamilyToText(out io.Writer, in *dto.MetricFamily) (written int, err e
 		}
 		written += n
 		if err != nil {
-			return
+			return written, err
 		}
 	}
-	return
+	return written, nil
 }
 
-// writeSample writes a single sample in text format to w, given the metric
+// writeSample writes a single sample in text format to out, given the metric
 // name, the metric proto message itself, optionally an additional label name
-// with a float64 value (use empty string as label name if not required), and
-// the value. The function returns the number of bytes written and any error
-// encountered.
+// and value (use empty strings if not required), and the value. The function
+// returns the number of bytes written and any error encountered.
 func writeSample(
-	w enhancedWriter,
-	name, suffix string,
+	name string,
 	metric *dto.Metric,
-	additionalLabelName string, additionalLabelValue float64,
+	additionalLabelName, additionalLabelValue string,
 	value float64,
+	out io.Writer,
 ) (int, error) {
 	var written int
-	n, err := w.WriteString(name)
+	n, err := fmt.Fprint(out, name)
 	written += n
 	if err != nil {
 		return written, err
 	}
-	if suffix != "" {
-		n, err = w.WriteString(suffix)
-		written += n
-		if err != nil {
-			return written, err
-		}
-	}
-	n, err = writeLabelPairs(
-		w, metric.Label, additionalLabelName, additionalLabelValue,
+	n, err = labelPairsToText(
+		metric.Label,
+		additionalLabelName, additionalLabelValue,
+		out,
 	)
 	written += n
 	if err != nil {
 		return written, err
 	}
-	err = w.WriteByte(' ')
-	written++
-	if err != nil {
-		return written, err
-	}
-	n, err = writeFloat(w, value)
+	n, err = fmt.Fprintf(out, " %v", value)
 	written += n
 	if err != nil {
 		return written, err
 	}
 	if metric.TimestampMs != nil {
-		err = w.WriteByte(' ')
-		written++
-		if err != nil {
-			return written, err
-		}
-		n, err = writeInt(w, *metric.TimestampMs)
+		n, err = fmt.Fprintf(out, " %v", *metric.TimestampMs)
 		written += n
 		if err != nil {
 			return written, err
 		}
 	}
-	err = w.WriteByte('\n')
-	written++
+	n, err = out.Write([]byte{'\n'})
+	written += n
 	if err != nil {
 		return written, err
 	}
 	return written, nil
 }
 
-// writeLabelPairs converts a slice of LabelPair proto messages plus the
+// labelPairsToText converts a slice of LabelPair proto messages plus the
 // explicitly given additional label pair into text formatted as required by the
-// text format and writes it to 'w'. An empty slice in combination with an empty
-// string 'additionalLabelName' results in nothing being written. Otherwise, the
-// label pairs are written, escaped as required by the text format, and enclosed
-// in '{...}'. The function returns the number of bytes written and any error
-// encountered.
-func writeLabelPairs(
-	w enhancedWriter,
+// text format and writes it to 'out'. An empty slice in combination with an
+// empty string 'additionalLabelName' results in nothing being
+// written. Otherwise, the label pairs are written, escaped as required by the
+// text format, and enclosed in '{...}'. The function returns the number of
+// bytes written and any error encountered.
+func labelPairsToText(
 	in []*dto.LabelPair,
-	additionalLabelName string, additionalLabelValue float64,
+	additionalLabelName, additionalLabelValue string,
+	out io.Writer,
 ) (int, error) {
 	if len(in) == 0 && additionalLabelName == "" {
 		return 0, nil
 	}
-	var (
-		written   int
-		separator byte = '{'
-	)
+	var written int
+	separator := '{'
 	for _, lp := range in {
-		err := w.WriteByte(separator)
-		written++
-		if err != nil {
-			return written, err
-		}
-		n, err := w.WriteString(lp.GetName())
+		n, err := fmt.Fprintf(
+			out, `%c%s="%s"`,
+			separator, lp.GetName(), escapeString(lp.GetValue(), true),
+		)
 		written += n
 		if err != nil {
 			return written, err
 		}
-		n, err = w.WriteString(`="`)
-		written += n
-		if err != nil {
-			return written, err
-		}
-		n, err = writeEscapedString(w, lp.GetValue(), true)
-		written += n
-		if err != nil {
-			return written, err
-		}
-		err = w.WriteByte('"')
-		written++
-		if err != nil {
-			return written, err
-		}
 		separator = ','
 	}
 	if additionalLabelName != "" {
-		err := w.WriteByte(separator)
-		written++
-		if err != nil {
-			return written, err
-		}
-		n, err := w.WriteString(additionalLabelName)
+		n, err := fmt.Fprintf(
+			out, `%c%s="%s"`,
+			separator, additionalLabelName,
+			escapeString(additionalLabelValue, true),
+		)
 		written += n
 		if err != nil {
 			return written, err
 		}
-		n, err = w.WriteString(`="`)
-		written += n
-		if err != nil {
-			return written, err
-		}
-		n, err = writeFloat(w, additionalLabelValue)
-		written += n
-		if err != nil {
-			return written, err
-		}
-		err = w.WriteByte('"')
-		written++
-		if err != nil {
-			return written, err
-		}
 	}
-	err := w.WriteByte('}')
-	written++
+	n, err := out.Write([]byte{'}'})
+	written += n
 	if err != nil {
 		return written, err
 	}
 	return written, nil
 }
 
-// writeEscapedString replaces '\' by '\\', new line character by '\n', and - if
-// includeDoubleQuote is true - '"' by '\"'.
 var (
-	escaper       = strings.NewReplacer("\\", `\\`, "\n", `\n`)
-	quotedEscaper = strings.NewReplacer("\\", `\\`, "\n", `\n`, "\"", `\"`)
+	escape                = strings.NewReplacer("\\", `\\`, "\n", `\n`)
+	escapeWithDoubleQuote = strings.NewReplacer("\\", `\\`, "\n", `\n`, "\"", `\"`)
 )
 
-func writeEscapedString(w enhancedWriter, v string, includeDoubleQuote bool) (int, error) {
+// escapeString replaces '\' by '\\', new line character by '\n', and - if
+// includeDoubleQuote is true - '"' by '\"'.
+func escapeString(v string, includeDoubleQuote bool) string {
 	if includeDoubleQuote {
-		return quotedEscaper.WriteString(w, v)
-	} else {
-		return escaper.WriteString(w, v)
+		return escapeWithDoubleQuote.Replace(v)
 	}
-}
 
-// writeFloat is equivalent to fmt.Fprint with a float64 argument but hardcodes
-// a few common cases for increased efficiency. For non-hardcoded cases, it uses
-// strconv.AppendFloat to avoid allocations, similar to writeInt.
-func writeFloat(w enhancedWriter, f float64) (int, error) {
-	switch {
-	case f == 1:
-		return 1, w.WriteByte('1')
-	case f == 0:
-		return 1, w.WriteByte('0')
-	case f == -1:
-		return w.WriteString("-1")
-	case math.IsNaN(f):
-		return w.WriteString("NaN")
-	case math.IsInf(f, +1):
-		return w.WriteString("+Inf")
-	case math.IsInf(f, -1):
-		return w.WriteString("-Inf")
-	default:
-		bp := numBufPool.Get().(*[]byte)
-		*bp = strconv.AppendFloat((*bp)[:0], f, 'g', -1, 64)
-		written, err := w.Write(*bp)
-		numBufPool.Put(bp)
-		return written, err
-	}
-}
-
-// writeInt is equivalent to fmt.Fprint with an int64 argument but uses
-// strconv.AppendInt with a byte slice taken from a sync.Pool to avoid
-// allocations.
-func writeInt(w enhancedWriter, i int64) (int, error) {
-	bp := numBufPool.Get().(*[]byte)
-	*bp = strconv.AppendInt((*bp)[:0], i, 10)
-	written, err := w.Write(*bp)
-	numBufPool.Put(bp)
-	return written, err
+	return escape.Replace(v)
 }

vendor/github.com/prometheus/common/expfmt/text_parse.go

@@ -359,7 +359,7 @@ func (p *TextParser) startLabelValue() stateFn {
 		}
 		return p.readingValue
 	default:
-		p.parseError(fmt.Sprintf("unexpected end of label value %q", p.currentLabelPair.GetValue()))
+		p.parseError(fmt.Sprintf("unexpected end of label value %q", p.currentLabelPair.Value))
 		return nil
 	}
 }

vendor/github.com/prometheus/common/internal/bitbucket.org/ww/goautoneg/autoneg.go

@@ -1,12 +1,12 @@
 /*
-Copyright (c) 2011, Open Knowledge Foundation Ltd.
-All rights reserved.
-
 HTTP Content-Type Autonegotiation.
 
 The functions in this package implement the behaviour specified in
 http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html
 
+Copyright (c) 2011, Open Knowledge Foundation Ltd.
+All rights reserved.
+
 Redistribution and use in source and binary forms, with or without
 modification, are permitted provided that the following conditions are
 met:

vendor/github.com/prometheus/common/model/metric.go

@@ -21,6 +21,7 @@ import (
 )
 
 var (
+	separator = []byte{0}
 	// MetricNameRE is a regular expression matching valid metric
 	// names. Note that the IsValidMetricName function performs the same
 	// check but faster than a match with this regular expression.

vendor/github.com/prometheus/common/model/time.go

@@ -43,7 +43,7 @@ const (
 // (1970-01-01 00:00 UTC) excluding leap seconds.
 type Time int64
 
-// Interval describes an interval between two timestamps.
+// Interval describes and interval between two timestamps.
 type Interval struct {
 	Start, End Time
 }
@@ -150,13 +150,7 @@ func (t *Time) UnmarshalJSON(b []byte) error {
 			return err
 		}
 
-		// If the value was something like -0.1 the negative is lost in the
-		// parsing because of the leading zero, this ensures that we capture it.
-		if len(p[0]) > 0 && p[0][0] == '-' && v+va > 0 {
-			*t = Time(v+va) * -1
-		} else {
-			*t = Time(v + va)
-		}
+		*t = Time(v + va)
 
 	default:
 		return fmt.Errorf("invalid time %q", string(b))