feat: helmfile template --skip-cleanup (#1570)

* feat: `helmfile template --skip-cleanup`

Resolves #1517

pkg/app/app.go

@@ -218,6 +218,9 @@ func (a *App) Diff(c DiffConfigProvider) error {
 }
 
 func (a *App) Template(c TemplateConfigProvider) error {
+
+	opts := []LoadOption{SetRetainValuesFiles(c.SkipCleanup())}
+
 	return a.ForEachState(func(run *Run) (ok bool, errs []error) {
 		// `helm template` in helm v2 does not support local chart.
 		// So, we set forceDownload=true for helm v2 only
@@ -233,7 +236,7 @@ func (a *App) Template(c TemplateConfigProvider) error {
 		}
 
 		return
-	})
+	}, opts...)
 }
 
 func (a *App) WriteValues(c WriteValuesConfigProvider) error {
@@ -1437,6 +1440,7 @@ func (a *App) template(r *Run, c TemplateConfigProvider) (bool, []error) {
 				Set:               c.Set(),
 				IncludeCRDs:       c.IncludeCRDs(),
 				OutputDirTemplate: c.OutputDirTemplate(),
+				SkipCleanup:       c.SkipCleanup(),
 			}
 			return subst.TemplateReleases(helm, c.OutputDir(), c.Values(), args, c.Concurrency(), c.Validate(), opts)
 		}))

pkg/app/app_test.go

@@ -2241,6 +2241,7 @@ type configImpl struct {
 	set         []string
 	output      string
 	includeCRDs bool
+	skipCleanup bool
 	skipDeps    bool
 }
 
@@ -2264,6 +2265,10 @@ func (c configImpl) Validate() bool {
 	return true
 }
 
+func (c configImpl) SkipCleanup() bool {
+	return c.skipCleanup
+}
+
 func (c configImpl) SkipDeps() bool {
 	return c.skipDeps
 }

pkg/app/config.go

@@ -134,6 +134,7 @@ type TemplateConfigProvider interface {
 	OutputDirTemplate() string
 	Validate() bool
 	SkipDeps() bool
+	SkipCleanup() bool
 	OutputDir() string
 	IncludeCRDs() bool