Add integration with Hashicorp Vault, AWS SSM, SecretsManager (#906)

* feat: Add integration with Hashicorp Vault, AWS SSM, SecretsManager

Fields which are rendered: Release.Values, Release.SetValues.Value, Release.SetValues.Values

Example:
```
values:
- foo: ref+vault://mykv/foo?address=http://127.0.0.1:8200#/mykey
set:
- name: xyz
  values:
  - ref+vault://mykv/foo?address=http://127.0.0.1:8200#/mykey3
```

Resolves #881

* feat: Update integration with variantdev/vals

New ref+.\* secret formats are used:
https://github.com/variantdev/vals/tree/6565695a031f407a1066bdd31ae313db6a33ec0a#suported-backends

Resolves #881

pkg/app/app.go

@@ -13,6 +13,7 @@ import (
 	"github.com/roboll/helmfile/pkg/helmexec"
 	"github.com/roboll/helmfile/pkg/remote"
 	"github.com/roboll/helmfile/pkg/state"
+	"github.com/variantdev/vals"
 
 	"go.uber.org/zap"
 
@@ -20,6 +21,11 @@ import (
 	"sort"
 )
 
+const (
+	// cache size for improving performance of ref+.* secrets rendering
+	valsCacheSize = 512
+)
+
 type App struct {
 	KubeContext string
 	Logger      *zap.SugaredLogger
@@ -49,6 +55,8 @@ type App struct {
 	remote *remote.Remote
 
 	helmExecer helmexec.Interface
+
+	valsRuntime vals.Evaluator
 }
 
 func New(conf ConfigProvider) *App {
@@ -78,6 +86,13 @@ func Init(app *App) *App {
 	app.fileExistsAt = fileExistsAt
 	app.fileExists = fileExists
 	app.directoryExistsAt = directoryExistsAt
+
+	var err error
+	app.valsRuntime, err = vals.New(valsCacheSize)
+	if err != nil {
+		panic(fmt.Sprintf("Failed to initialize vals runtime: %v", err))
+	}
+
 	return app
 }
 
@@ -274,6 +289,7 @@ func (a *App) loadDesiredStateFromYaml(file string, opts ...LoadOpts) (*state.He
 		KubeContext: a.KubeContext,
 		glob:        a.glob,
 		helm:        a.helmExecer,
+		valsRuntime: a.valsRuntime,
 	}
 
 	var op LoadOpts

pkg/app/app_test.go

@@ -18,6 +18,7 @@ import (
 	"github.com/roboll/helmfile/pkg/helmexec"
 	"github.com/roboll/helmfile/pkg/state"
 	"github.com/roboll/helmfile/pkg/testhelper"
+	"github.com/variantdev/vals"
 
 	"go.uber.org/zap"
 	"gotest.tools/env"
@@ -440,8 +441,8 @@ func TestVisitDesiredStatesWithReleasesFiltered_EmbeddedSelectors(t *testing.T)
 helmfiles:
 - path: helmfile.d/a*.yaml
   selectors:
-  - name=prometheus      
-  - name=zipkin      
+  - name=prometheus
+  - name=zipkin
 - helmfile.d/b*.yaml
 - path: helmfile.d/c*.yaml
   selectors: []
@@ -1944,6 +1945,11 @@ releases:
 	var buffer bytes.Buffer
 	logger := helmexec.NewLogger(&buffer, "debug")
 
+	valsRuntime, err := vals.New(32)
+	if err != nil {
+		t.Errorf("unexpected error creating vals runtime: %v", err)
+	}
+
 	app := appWithFs(&App{
 		glob:        filepath.Glob,
 		abs:         filepath.Abs,
@@ -1952,6 +1958,7 @@ releases:
 		Logger:      logger,
 		helmExecer:  helm,
 		Namespace:   "testNamespace",
+		valsRuntime: valsRuntime,
 	}, files)
 	app.Template(configImpl{set: []string{"foo=a", "bar=b"}})
 

pkg/app/desired_state_file_loader.go

@@ -11,6 +11,7 @@ import (
 	"github.com/roboll/helmfile/pkg/environment"
 	"github.com/roboll/helmfile/pkg/helmexec"
 	"github.com/roboll/helmfile/pkg/state"
+	"github.com/variantdev/vals"
 	"go.uber.org/zap"
 )
 
@@ -26,8 +27,9 @@ type desiredStateLoader struct {
 	abs        func(string) (string, error)
 	glob       func(string) ([]string, error)
 
-	logger *zap.SugaredLogger
-	helm   helmexec.Interface
+	logger      *zap.SugaredLogger
+	helm        helmexec.Interface
+	valsRuntime vals.Evaluator
 }
 
 func (ld *desiredStateLoader) Load(f string, opts LoadOpts) (*state.HelmState, error) {
@@ -128,7 +130,7 @@ func (ld *desiredStateLoader) loadFileWithOverrides(inheritedEnv, overrodeEnv *e
 }
 
 func (a *desiredStateLoader) underlying() *state.StateCreator {
-	c := state.NewCreator(a.logger, a.readFile, a.fileExists, a.abs, a.glob, a.helm)
+	c := state.NewCreator(a.logger, a.readFile, a.fileExists, a.abs, a.glob, a.helm, a.valsRuntime)
 	c.LoadFile = a.loadFile
 	return c
 }