From 0858dc865d3854d451981268a7ee27d2186c43b8 Mon Sep 17 00:00:00 2001
From: davidnewhall2 <david@sleepers.pro>
Date: Fri, 26 Jun 2020 01:29:58 -0700
Subject: [PATCH] extend output interface. fix mutexes

---
 core/poller/config.go  |  1 +
 core/poller/inputs.go  | 24 +++++++++++++++++++++---
 core/poller/outputs.go | 31 +++++++++++++++++++++++++++----
 3 files changed, 49 insertions(+), 7 deletions(-)

diff --git a/core/poller/config.go b/core/poller/config.go
index 0f13cb8e..f3a982f0 100644
--- a/core/poller/config.go
+++ b/core/poller/config.go
@@ -43,6 +43,7 @@ type Metrics struct {
 	Devices    []interface{}
 }
 
+// Events defines the type for log entries.
 type Events struct {
 	Logs []interface{}
 }
diff --git a/core/poller/inputs.go b/core/poller/inputs.go
index 85753d28..a2882f62 100644
--- a/core/poller/inputs.go
+++ b/core/poller/inputs.go
@@ -9,7 +9,7 @@ import (
 var (
 	// These are used ot keep track of loaded input plugins.
 	inputs    []*InputPlugin // nolint: gochecknoglobals
-	inputSync sync.Mutex     // nolint: gochecknoglobals
+	inputSync sync.RWMutex   // nolint: gochecknoglobals
 )
 
 // Input plugins must implement this interface.
@@ -58,8 +58,8 @@ func NewInput(i *InputPlugin) {
 
 // InitializeInputs runs the passed-in initializer method for each input plugin.
 func (u *UnifiPoller) InitializeInputs() error {
-	inputSync.Lock()
-	defer inputSync.Unlock()
+	inputSync.RLock()
+	defer inputSync.RUnlock()
 
 	for _, input := range inputs {
 		// This must return, or the app locks up here.
@@ -73,6 +73,9 @@ func (u *UnifiPoller) InitializeInputs() error {
 
 // Events aggregates log messages (events) from one or more sources.
 func (u *UnifiPoller) Events(filter *Filter) (*Events, error) {
+	inputSync.RLock()
+	defer inputSync.RUnlock()
+
 	events := Events{}
 
 	for _, input := range inputs {
@@ -97,6 +100,9 @@ func (u *UnifiPoller) Events(filter *Filter) (*Events, error) {
 // Metrics aggregates all the measurements from filtered inputs and returns them.
 // Passing a null filter returns everything!
 func (u *UnifiPoller) Metrics(filter *Filter) (*Metrics, error) {
+	inputSync.RLock()
+	defer inputSync.RUnlock()
+
 	metrics := &Metrics{}
 
 	for _, input := range inputs {
@@ -135,3 +141,15 @@ func AppendMetrics(existing *Metrics, m *Metrics) *Metrics {
 
 	return existing
 }
+
+// Inputs allows output plugins to see the list of loaded input plugins.
+func (u *UnifiPoller) Inputs() (names []string) {
+	inputSync.RLock()
+	defer inputSync.RUnlock()
+
+	for i := range inputs {
+		names = append(names, inputs[i].Name)
+	}
+
+	return names
+}
diff --git a/core/poller/outputs.go b/core/poller/outputs.go
index ad90b9ad..f0b5541e 100644
--- a/core/poller/outputs.go
+++ b/core/poller/outputs.go
@@ -7,18 +7,21 @@ import (
 
 var (
 	// These are used to keep track of loaded output plugins.
-	outputs             []*Output  // nolint: gochecknoglobals
-	outputSync          sync.Mutex // nolint: gochecknoglobals
+	outputs             []*Output    // nolint: gochecknoglobals
+	outputSync          sync.RWMutex // nolint: gochecknoglobals
 	errNoOutputPlugins  = fmt.Errorf("no output plugins imported")
 	errAllOutputStopped = fmt.Errorf("all output plugins have stopped, or none enabled")
 )
 
 // Collect is passed into output packages so they may collect metrics to output.
-// Output packages must implement this interface.
 type Collect interface {
+	Logger
 	Metrics(*Filter) (*Metrics, error)
 	Events(*Filter) (*Events, error)
-	Logger
+	// These get used by the webserver output plugin.
+	Poller() Poller
+	Inputs() []string
+	Outputs() []string
 }
 
 // Output defines the output data for a metric exporter like influx or prometheus.
@@ -41,9 +44,17 @@ func NewOutput(o *Output) {
 	outputs = append(outputs, o)
 }
 
+// Poller returns the poller config.
+func (u *UnifiPoller) Poller() Poller {
+	return *u.Config.Poller
+}
+
 // InitializeOutputs runs all the configured output plugins.
 // If none exist, or they all exit an error is returned.
 func (u *UnifiPoller) InitializeOutputs() error {
+	outputSync.RLock()
+	defer outputSync.RUnlock()
+
 	v := make(chan error)
 	defer close(v)
 
@@ -73,3 +84,15 @@ func (u *UnifiPoller) InitializeOutputs() error {
 
 	return nil
 }
+
+// Outputs allows other output plugins to see the list of loaded output plugins.
+func (u *UnifiPoller) Outputs() (names []string) {
+	outputSync.RLock()
+	defer outputSync.RUnlock()
+
+	for i := range outputs {
+		names = append(names, outputs[i].Name)
+	}
+
+	return names
+}