Add the ability to load a remote environment values file (#1296)

Enables the user to specify a remote path for an environment values file, e.g.,

```yaml
environments:
  cluster-azure-us-west:
    values:
      - git::https://git.company.org/helmfiles/global/azure.yaml?ref=master
      - git::https://git.company.org/helmfiles/global/us-west.yaml?ref=master
  cluster-gcp-europe-west:
    values:
      - git::https://git.company.org/helmfiles/global/gcp.yaml?ref=master
      - git::https://git.company.org/helmfiles/global/europe-west.yaml?ref=master

releases:
  - ...
```

This is particularly useful when you co-locate helmfiles within your project repo but want to reuse the definitions in a global repo.

pkg/state/create.go

@@ -5,6 +5,7 @@ import (
 	"errors"
 	"fmt"
 	"github.com/roboll/helmfile/pkg/helmexec"
+	"github.com/roboll/helmfile/pkg/remote"
 	"io"
 	"os"
 
@@ -52,9 +53,11 @@ type StateCreator struct {
 	getHelm func(*HelmState) helmexec.Interface
 
 	overrideHelmBinary string
+
+	remote *remote.Remote
 }
 
-func NewCreator(logger *zap.SugaredLogger, readFile func(string) ([]byte, error), fileExists func(string) (bool, error), abs func(string) (string, error), glob func(string) ([]string, error), valsRuntime vals.Evaluator, getHelm func(*HelmState) helmexec.Interface, overrideHelmBinary string) *StateCreator {
+func NewCreator(logger *zap.SugaredLogger, readFile func(string) ([]byte, error), fileExists func(string) (bool, error), abs func(string) (string, error), glob func(string) ([]string, error), valsRuntime vals.Evaluator, getHelm func(*HelmState) helmexec.Interface, overrideHelmBinary string, remote *remote.Remote) *StateCreator {
 	return &StateCreator{
 		logger:      logger,
 		readFile:    readFile,
@@ -66,6 +69,8 @@ func NewCreator(logger *zap.SugaredLogger, readFile func(string) ([]byte, error)
 		getHelm:     getHelm,
 
 		overrideHelmBinary: overrideHelmBinary,
+
+		remote: remote,
 	}
 }
 
@@ -139,7 +144,7 @@ func (c *StateCreator) LoadEnvValues(target *HelmState, env string, ctxEnv *envi
 		return nil, &StateLoadError{fmt.Sprintf("failed to read %s", state.FilePath), err}
 	}
 
-	e.Defaults, err = state.loadValuesEntries(nil, state.DefaultValues)
+	e.Defaults, err = state.loadValuesEntries(nil, state.DefaultValues, c.remote)
 	if err != nil {
 		return nil, err
 	}
@@ -203,7 +208,7 @@ func (c *StateCreator) loadEnvValues(st *HelmState, name string, failOnMissingEn
 	envSpec, ok := st.Environments[name]
 	if ok {
 		var err error
-		envVals, err = st.loadValuesEntries(envSpec.MissingFileHandler, envSpec.Values)
+		envVals, err = st.loadValuesEntries(envSpec.MissingFileHandler, envSpec.Values, c.remote)
 		if err != nil {
 			return nil, err
 		}
@@ -321,11 +326,11 @@ func (c *StateCreator) scatterGatherEnvSecretFiles(st *HelmState, envSecretFiles
 	return nil
 }
 
-func (st *HelmState) loadValuesEntries(missingFileHandler *string, entries []interface{}) (map[string]interface{}, error) {
+func (st *HelmState) loadValuesEntries(missingFileHandler *string, entries []interface{}, remote *remote.Remote) (map[string]interface{}, error) {
 	envVals := map[string]interface{}{}
 
 	valuesEntries := append([]interface{}{}, entries...)
-	ld := NewEnvironmentValuesLoader(st.storage(), st.readFile, st.logger)
+	ld := NewEnvironmentValuesLoader(st.storage(), st.readFile, st.logger, remote)
 	var err error
 	envVals, err = ld.LoadEnvironmentValues(missingFileHandler, valuesEntries)
 	if err != nil {

pkg/state/create_test.go

@@ -1,6 +1,7 @@
 package state
 
 import (
+	"github.com/roboll/helmfile/pkg/remote"
 	"io/ioutil"
 	"path/filepath"
 	"reflect"
@@ -108,7 +109,9 @@ bar: {{ readFile "bar.txt" }}
 	})
 	testFs.Cwd = "/example/path/to"
 
-	state, err := NewCreator(logger, testFs.ReadFile, testFs.FileExists, testFs.Abs, testFs.Glob, nil, nil, "").ParseAndLoad(yamlContent, filepath.Dir(yamlFile), yamlFile, "production", true, nil)
+	r := remote.NewRemote(logger, testFs.Cwd, testFs.ReadFile, testFs.DirectoryExistsAt, testFs.FileExistsAt)
+	state, err := NewCreator(logger, testFs.ReadFile, testFs.FileExists, testFs.Abs, testFs.Glob, nil, nil, "", r).
+		ParseAndLoad(yamlContent, filepath.Dir(yamlFile), yamlFile, "production", true, nil)
 	if err != nil {
 		t.Fatalf("unexpected error: %v", err)
 	}

pkg/state/envvals_loader.go

@@ -5,6 +5,7 @@ import (
 	"github.com/imdario/mergo"
 	"github.com/roboll/helmfile/pkg/environment"
 	"github.com/roboll/helmfile/pkg/maputil"
+	"github.com/roboll/helmfile/pkg/remote"
 	"github.com/roboll/helmfile/pkg/tmpl"
 	"go.uber.org/zap"
 	"gopkg.in/yaml.v2"
@@ -17,13 +18,16 @@ type EnvironmentValuesLoader struct {
 	readFile func(string) ([]byte, error)
 
 	logger *zap.SugaredLogger
+
+	remote *remote.Remote
 }
 
-func NewEnvironmentValuesLoader(storage *Storage, readFile func(string) ([]byte, error), logger *zap.SugaredLogger) *EnvironmentValuesLoader {
+func NewEnvironmentValuesLoader(storage *Storage, readFile func(string) ([]byte, error), logger *zap.SugaredLogger, remote *remote.Remote) *EnvironmentValuesLoader {
 	return &EnvironmentValuesLoader{
 		storage:  storage,
 		readFile: readFile,
 		logger:   logger,
+		remote:   remote,
 	}
 }
 
@@ -36,6 +40,11 @@ func (ld *EnvironmentValuesLoader) LoadEnvironmentValues(missingFileHandler *str
 		switch strOrMap := entry.(type) {
 		case string:
 			urlOrPath := strOrMap
+			localPath, err := ld.remote.Locate(urlOrPath)
+			if err == nil {
+				urlOrPath = localPath
+			}
+
 			files, skipped, err := ld.storage.resolveFile(missingFileHandler, "environment values", urlOrPath)
 			if err != nil {
 				return nil, err

pkg/state/envvals_loader_test.go

@@ -2,6 +2,7 @@ package state
 
 import (
 	"github.com/google/go-cmp/cmp"
+	"github.com/roboll/helmfile/pkg/remote"
 	"go.uber.org/zap"
 	"io/ioutil"
 	"path/filepath"
@@ -23,7 +24,10 @@ func newLoader() *EnvironmentValuesLoader {
 		logger:   sugar,
 	}
 
-	return NewEnvironmentValuesLoader(storage, ioutil.ReadFile, sugar)
+	readFile := func(s string) ([]byte, error) { return []byte{}, nil }
+	dirExists := func(d string) bool { return false }
+	fileExists := func(f string) bool { return false }
+	return NewEnvironmentValuesLoader(storage, ioutil.ReadFile, sugar, remote.NewRemote(sugar, "/tmp", readFile, dirExists, fileExists))
 }
 
 // See https://github.com/roboll/helmfile/pull/1169