Implment `--dry-run=["none"|"client"|"server"] install/upgrade/template flag

Signed-off-by: George Jenkins <gjenkins8@bloomberg.net>

cmd/helm/install.go

@@ -122,10 +122,26 @@ To see the list of chart repositories, use 'helm repo list'. To search for
 charts in a repository, use 'helm search'.
 `
 
+func determineInstallDryRunMode(dryRunModeFlag string) (*action.DryRunMode, error) {
+	switch dryRunModeFlag {
+	case "none":
+	case "false": // TODO: Remove "false" helm v4
+		return &action.DryRunModeNone, nil
+	case "client":
+	case "true": // TODO: Remove "true" helm v4
+		return &action.DryRunModeClient, nil
+	case "server":
+		return &action.DryRunModeServer, nil
+	}
+
+	return nil, fmt.Errorf("Invalid --dry-run flag value: %s", dryRunModeFlag)
+}
+
 func newInstallCmd(cfg *action.Configuration, out io.Writer) *cobra.Command {
 	client := action.NewInstall(cfg)
 	valueOpts := &values.Options{}
 	var outfmt output.Format
+	var dryRunModeFlag string
 
 	cmd := &cobra.Command{
 		Use:   "install [NAME] [CHART]",
@@ -136,6 +152,15 @@ func newInstallCmd(cfg *action.Configuration, out io.Writer) *cobra.Command {
 			return compInstall(args, toComplete, client)
 		},
 		RunE: func(_ *cobra.Command, args []string) error {
+
+			dryRunMode, err := determineInstallDryRunMode(dryRunModeFlag)
+			if err != nil {
+				return err
+			}
+
+			client.DryRunMode = *dryRunMode
+			fmt.Printf("drm: %s\n", client.DryRunMode)
+
 			rel, err := runInstall(args, client, valueOpts, out)
 			if err != nil {
 				return errors.Wrap(err, "INSTALLATION FAILED")
@@ -145,16 +170,21 @@ func newInstallCmd(cfg *action.Configuration, out io.Writer) *cobra.Command {
 		},
 	}
 
-	addInstallFlags(cmd, cmd.Flags(), client, valueOpts)
+	addInstallFlags(cmd, cmd.Flags(), client, &dryRunModeFlag, valueOpts)
 	bindOutputFlag(cmd, &outfmt)
 	bindPostRenderFlag(cmd, &client.PostRenderer)
 
 	return cmd
 }
 
-func addInstallFlags(cmd *cobra.Command, f *pflag.FlagSet, client *action.Install, valueOpts *values.Options) {
+func addInstallFlags(cmd *cobra.Command, f *pflag.FlagSet, client *action.Install, dryRunModeFlag *string, valueOpts *values.Options) {
 	f.BoolVar(&client.CreateNamespace, "create-namespace", false, "create the release namespace if not present")
-	f.BoolVar(&client.DryRun, "dry-run", false, "simulate an install")
+	f.StringVar(
+		dryRunModeFlag,
+		"dry-run",
+		"none",
+		`simulate an install. Must be "none", "server", or "client". If client strategy, X. If server strategy, Y. For backwards compatibility, boolean values "true" and "false" are also accepted. "true" being a synonym for "client". "false" meaning disable dry-run`,
+	)
 	f.BoolVar(&client.Force, "force", false, "force resource updates through a replacement strategy")
 	f.BoolVar(&client.DisableHooks, "no-hooks", false, "prevent hooks from running during install")
 	f.BoolVar(&client.Replace, "replace", false, "re-use the given name, only if that name is a deleted release which remains in the history. This is unsafe in production")

cmd/helm/template.go

@@ -46,10 +46,28 @@ faked locally. Additionally, none of the server-side testing of chart validity
 (e.g. whether an API is supported) is done.
 `
 
+func determineTemplateDryRunMode(dryRunModeFlag string) (*action.DryRunMode, error) {
+	switch dryRunModeFlag {
+	case "none":
+		return nil, fmt.Errorf("Invalid flag --dry-run=none for template")
+	case "false": // TODO: Remove "false" helm v4
+		// helm template --dry-run=false was previously ignored, and dry-run set anyway
+		return &action.DryRunModeClient, nil
+	case "client":
+	case "true": // TODO: Remove "true" helm v4
+		return &action.DryRunModeClient, nil
+	case "server":
+		return &action.DryRunModeServer, nil
+	}
+
+	return nil, fmt.Errorf("Invalid --dry-run flag value: %s", dryRunModeFlag)
+}
+
 func newTemplateCmd(cfg *action.Configuration, out io.Writer) *cobra.Command {
 	var validate bool
 	var includeCrds bool
 	var skipTests bool
+	var dryRunModeFlag string
 	client := action.NewInstall(cfg)
 	valueOpts := &values.Options{}
 	var kubeVersion string
@@ -73,7 +91,12 @@ func newTemplateCmd(cfg *action.Configuration, out io.Writer) *cobra.Command {
 				client.KubeVersion = parsedKubeVersion
 			}
 
+			dryRunMode, err := determineTemplateDryRunMode(dryRunModeFlag)
+			if err != nil {
+				return err
+			}
 			client.DryRun = true
+			client.DryRunMode = *dryRunMode
 			client.ReleaseName = "release-name"
 			client.Replace = true // Skip the name check
 			client.ClientOnly = !validate
@@ -173,7 +196,7 @@ func newTemplateCmd(cfg *action.Configuration, out io.Writer) *cobra.Command {
 	}
 
 	f := cmd.Flags()
-	addInstallFlags(cmd, f, client, valueOpts)
+	addInstallFlags(cmd, f, client, &dryRunModeFlag, valueOpts)
 	f.StringArrayVarP(&showFiles, "show-only", "s", []string{}, "only show manifests rendered from the given templates")
 	f.StringVar(&client.OutputDir, "output-dir", "", "writes the executed templates to files in output-dir instead of stdout")
 	f.BoolVar(&validate, "validate", false, "validate your manifests against the Kubernetes cluster you are currently pointing at. This is the same validation performed on an install")

pkg/action/install.go

@@ -62,6 +62,14 @@ const notesFileSuffix = "NOTES.txt"
 
 const defaultDirectoryPermission = 0755
 
+type DryRunMode string
+
+var (
+	DryRunModeNone   DryRunMode = "none"
+	DryRunModeClient DryRunMode = "client"
+	DryRunModeServer DryRunMode = "server"
+)
+
 // Install performs an installation operation.
 type Install struct {
 	cfg *Configuration
@@ -71,7 +79,8 @@ type Install struct {
 	ClientOnly               bool
 	Force                    bool
 	CreateNamespace          bool
-	DryRun                   bool
+	DryRun                   bool // Deprecated: replaced by DryRunMode, to be removed helm v4
+	DryRunMode               DryRunMode
 	DisableHooks             bool
 	Replace                  bool
 	Wait                     bool
@@ -179,7 +188,7 @@ func (i *Install) installCRDs(crds []chart.CRD) error {
 
 // Run executes the installation
 //
-// If DryRun is set to true, this will prepare the release, but not install it
+// If DryRunMode is not 'none', this will prepare the release, but not install it
 
 func (i *Install) Run(chrt *chart.Chart, vals map[string]interface{}) (*release.Release, error) {
 	ctx := context.Background()
@@ -207,7 +216,7 @@ func (i *Install) RunWithContext(ctx context.Context, chrt *chart.Chart, vals ma
 	// contacts the upstream server and builds the capabilities object.
 	if crds := chrt.CRDObjects(); !i.ClientOnly && !i.SkipCRDs && len(crds) > 0 {
 		// On dry run, bail here
-		if i.DryRun {
+		if i.isDryRun() {
 			i.cfg.Log("WARNING: This chart or one of its subcharts contains CRDs. Rendering may fail or contain inaccuracies.")
 		} else if err := i.installCRDs(crds); err != nil {
 			return nil, err
@@ -241,7 +250,7 @@ func (i *Install) RunWithContext(ctx context.Context, chrt *chart.Chart, vals ma
 	}
 
 	// special case for helm template --is-upgrade
-	isUpgrade := i.IsUpgrade && i.DryRun
+	isUpgrade := i.IsUpgrade && i.isDryRun()
 	options := chartutil.ReleaseOptions{
 		Name:      i.ReleaseName,
 		Namespace: i.Namespace,
@@ -298,7 +307,7 @@ func (i *Install) RunWithContext(ctx context.Context, chrt *chart.Chart, vals ma
 	}
 
 	// Bail out here if it is a dry run
-	if i.DryRun {
+	if i.isDryRun() {
 		rel.Info.Description = "Dry run complete"
 		return rel, nil
 	}
@@ -453,6 +462,23 @@ func (i *Install) failRelease(rel *release.Release, err error) (*release.Release
 	return rel, err
 }
 
+func (i *Install) isDryRun() bool {
+	if i.DryRunMode != "" {
+		switch i.DryRunMode {
+		case DryRunModeClient:
+		case DryRunModeServer:
+			return true
+		case DryRunModeNone:
+			return false
+		default:
+			panic("Invalid DryRun mode")
+		}
+	}
+
+	// Fallback to legacy
+	return i.DryRun
+}
+
 // availableName tests whether a name is available
 //
 // Roughly, this will return an error if name is
@@ -467,7 +493,8 @@ func (i *Install) availableName() error {
 	if err := chartutil.ValidateReleaseName(start); err != nil {
 		return errors.Wrapf(err, "release name %q", start)
 	}
-	if i.DryRun {
+
+	if i.isDryRun() {
 		return nil
 	}