feat(helm): add ability for a dry-run to evaluate lookup functions

When a helm command is run with the --dry-run-option=server flag, it will try to connect to the cluster
to be able to render lookup functions.
Closes #8137

Signed-off-by: Tapas Kapadia <tapaskapadia10@gmail.com>

cmd/helm/install.go

@@ -154,8 +154,9 @@ func newInstallCmd(cfg *action.Configuration, out io.Writer) *cobra.Command {
 
 func addInstallFlags(cmd *cobra.Command, f *pflag.FlagSet, client *action.Install, valueOpts *values.Options) {
 	f.BoolVar(&client.CreateNamespace, "create-namespace", false, "create the release namespace if not present")
-	f.StringVar(&client.DryRun, "dry-run", "none", "simulate an install. If --dry-run is set with no option being specified or as 'client', it will not attempt cluster connections. Setting option as 'server' allows attempting cluster connections.")
+	f.BoolVar(&client.DryRun, "dry-run", false, "simulate an install")
-	f.Lookup("dry-run").NoOptDefVal = "client"
+	f.StringVar(&client.DryRunOption, "dry-run-option", "none", "simulate an install. If --dry-run is set with no option being specified or as 'client', it will not attempt cluster connections. Setting option as 'server' allows attempting cluster connections.")
+	f.Lookup("dry-run-option").NoOptDefVal = "client"
 	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")
@@ -174,6 +175,8 @@ func addInstallFlags(cmd *cobra.Command, f *pflag.FlagSet, client *action.Instal
 	addValueOptionsFlags(f, valueOpts)
 	addChartPathOptionsFlags(f, &client.ChartPathOptions)
 
+	cmd.MarkFlagsMutuallyExclusive("dry-run", "dry-run-option")
+
 	err := cmd.RegisterFlagCompletionFunc("version", func(cmd *cobra.Command, args []string, toComplete string) ([]string, cobra.ShellCompDirective) {
 		requiredArgs := 2
 		if client.GenerateName {
@@ -263,7 +266,7 @@ func runInstall(args []string, client *action.Install, valueOpts *values.Options
 	client.Namespace = settings.Namespace()
 
 	// validate dry-run flag value is one of the allowed values
-	if err := validateDryRunFlag(client.DryRun); err != nil {
+	if err := validateDryRunOptionFlag(client.DryRunOption); err != nil {
 		return nil, err
 	}
 
@@ -308,12 +311,12 @@ func compInstall(args []string, toComplete string, client *action.Install) ([]st
 	return nil, cobra.ShellCompDirectiveNoFileComp
 }
 
-func validateDryRunFlag(dryRunFlagValue string) error {
+func validateDryRunOptionFlag(dryRunOptionFlagValue string) error {
 	// validate dry-run flag value with set of allowed value
 	allowedDryRunValues := []string{"false", "true", "none", "client", "server"}
 	isAllowed := false
 	for _, v := range allowedDryRunValues {
-		if dryRunFlagValue == v {
+		if dryRunOptionFlagValue == v {
 			isAllowed = true
 			break
 		}

cmd/helm/template.go

@@ -73,7 +73,6 @@ func newTemplateCmd(cfg *action.Configuration, out io.Writer) *cobra.Command {
 				client.KubeVersion = parsedKubeVersion
 			}
 
-			client.DryRun = "client"
 			client.ReleaseName = "release-name"
 			client.Replace = true // Skip the name check
 			client.ClientOnly = !validate

cmd/helm/upgrade.go

@@ -106,6 +106,7 @@ func newUpgradeCmd(cfg *action.Configuration, out io.Writer) *cobra.Command {
 					instClient.ChartPathOptions = client.ChartPathOptions
 					instClient.Force = client.Force
 					instClient.DryRun = client.DryRun
+					instClient.DryRunOption = client.DryRunOption
 					instClient.DisableHooks = client.DisableHooks
 					instClient.SkipCRDs = client.SkipCRDs
 					instClient.Timeout = client.Timeout
@@ -119,7 +120,6 @@ func newUpgradeCmd(cfg *action.Configuration, out io.Writer) *cobra.Command {
 					instClient.SubNotes = client.SubNotes
 					instClient.Description = client.Description
 					instClient.DependencyUpdate = client.DependencyUpdate
-
 					rel, err := runInstall(args, instClient, valueOpts, out)
 					if err != nil {
 						return err
@@ -140,7 +140,7 @@ func newUpgradeCmd(cfg *action.Configuration, out io.Writer) *cobra.Command {
 				return err
 			}
 			// validate dry-run flag value is one of the allowed values
-			if err := validateDryRunFlag(client.DryRun); err != nil {
+			if err := validateDryRunOptionFlag(client.DryRunOption); err != nil {
 				return err
 			}
 
@@ -218,8 +218,9 @@ func newUpgradeCmd(cfg *action.Configuration, out io.Writer) *cobra.Command {
 	f.BoolVar(&createNamespace, "create-namespace", false, "if --install is set, create the release namespace if not present")
 	f.BoolVarP(&client.Install, "install", "i", false, "if a release by this name doesn't already exist, run an install")
 	f.BoolVar(&client.Devel, "devel", false, "use development versions, too. Equivalent to version '>0.0.0-0'. If --version is set, this is ignored")
-	f.StringVar(&client.DryRun, "dry-run", "none", "simulate an install. If --dry-run is set with no option being specified or as 'client', it will not attempt cluster connections. Setting option as 'server' allows attempting cluster connections.")
+	f.BoolVar(&client.DryRun, "dry-run", false, "simulate an upgrade")
-	f.Lookup("dry-run").NoOptDefVal = "client"
+	f.StringVar(&client.DryRunOption, "dry-run-option", "none", "simulate an install. If --dry-run is set with no option being specified or as 'client', it will not attempt cluster connections. Setting option as 'server' allows attempting cluster connections.")
+	f.Lookup("dry-run-option").NoOptDefVal = "client"
 	f.BoolVar(&client.Recreate, "recreate-pods", false, "performs pods restart for the resource if applicable")
 	f.MarkDeprecated("recreate-pods", "functionality will no longer be updated. Consult the documentation for other methods to recreate pods")
 	f.BoolVar(&client.Force, "force", false, "force resource updates through a replacement strategy")
@@ -242,6 +243,8 @@ func newUpgradeCmd(cfg *action.Configuration, out io.Writer) *cobra.Command {
 	bindOutputFlag(cmd, &outfmt)
 	bindPostRenderFlag(cmd, &client.PostRenderer)
 
+	cmd.MarkFlagsMutuallyExclusive("dry-run", "dry-run-option")
+
 	err := cmd.RegisterFlagCompletionFunc("version", func(cmd *cobra.Command, args []string, toComplete string) ([]string, cobra.ShellCompDirective) {
 		if len(args) != 2 {
 			return nil, cobra.ShellCompDirectiveNoFileComp

pkg/action/action.go

@@ -102,7 +102,7 @@ type Configuration struct {
 // TODO: This function is badly in need of a refactor.
 // TODO: As part of the refactor the duplicate code in cmd/helm/template.go should be removed
 //       This code has to do with writing files to disk.
-func (cfg *Configuration) renderResources(ch *chart.Chart, values chartutil.Values, releaseName, outputDir string, subNotes, useReleaseName, includeCrds bool, pr postrender.PostRenderer, dryRun string) ([]*release.Hook, *bytes.Buffer, string, error) {
+func (cfg *Configuration) renderResources(ch *chart.Chart, values chartutil.Values, releaseName, outputDir string, subNotes, useReleaseName, includeCrds bool, pr postrender.PostRenderer, interactWithRemote bool) ([]*release.Hook, *bytes.Buffer, string, error) {
 	hs := []*release.Hook{}
 	b := bytes.NewBuffer(nil)
 
@@ -121,11 +121,11 @@ func (cfg *Configuration) renderResources(ch *chart.Chart, values chartutil.Valu
 	var err2 error
 
 	// A `helm template`  should not talk to the remote cluster. However, commands
-	// with `--dry-run` with the value of false, none, or sever should try to connect to the cluster.
+	// with the flag `--dry-run-option` with the value of false, none, or sever  
-	// This enables the ability to render 'lookup' functions.
+	// or with the flag `--dry-run` with the value of false should try to interact with the cluster.
 	// It may break in interesting and exotic ways because other data (e.g. discovery)
 	// is mocked.
-	if (dryRun == "server" || dryRun == "none" || dryRun == "false") && cfg.RESTClientGetter != nil {
+	if interactWithRemote && cfg.RESTClientGetter != nil {
 		restConfig, err := cfg.RESTClientGetter.ToRESTConfig()
 		if err != nil {
 			return hs, b, "", err

pkg/action/install.go

@@ -71,7 +71,8 @@ type Install struct {
 	ClientOnly               bool
 	Force                    bool
 	CreateNamespace          bool
-	DryRun                   string
+	DryRun                   bool
+	DryRunOption             string
 	DisableHooks             bool
 	Replace                  bool
 	Wait                     bool
@@ -128,8 +129,6 @@ type ChartPathOptions struct {
 func NewInstall(cfg *Configuration) *Install {
 	in := &Install{
 		cfg: cfg,
-		// Set default value of DryRun for before flags are binded (tests)
-		DryRun: "none",
 	}
 	in.ChartPathOptions.registryClient = cfg.RegistryClient
 
@@ -205,11 +204,21 @@ func (i *Install) RunWithContext(ctx context.Context, chrt *chart.Chart, vals ma
 		return nil, err
 	}
 
+	// determine dry run behavior
+	if i.DryRun || i.DryRunOption == "client" || i.DryRunOption == "server" || i.DryRunOption == "true" {
+		i.DryRun = true
+	}
+
+	var interactWithRemote bool
+	if !i.DryRun || i.DryRunOption == "server" {
+		interactWithRemote = true
+	}
+
 	// Pre-install anything in the crd/ directory. We do this before Helm
 	// 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 != "none" && i.DryRun != "false" {
+		if i.DryRun {
 			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
@@ -243,7 +252,7 @@ func (i *Install) RunWithContext(ctx context.Context, chrt *chart.Chart, vals ma
 	}
 
 	// special case for helm template --is-upgrade
-	isUpgrade := i.IsUpgrade && (i.DryRun != "none" && i.DryRun != "false")
+	isUpgrade := i.IsUpgrade && i.DryRun
 	options := chartutil.ReleaseOptions{
 		Name:      i.ReleaseName,
 		Namespace: i.Namespace,
@@ -259,8 +268,7 @@ func (i *Install) RunWithContext(ctx context.Context, chrt *chart.Chart, vals ma
 	rel := i.createRelease(chrt, vals)
 
 	var manifestDoc *bytes.Buffer
-
+	rel.Hooks, manifestDoc, rel.Info.Notes, err = i.cfg.renderResources(chrt, valuesToRender, i.ReleaseName, i.OutputDir, i.SubNotes, i.UseReleaseName, i.IncludeCRDs, i.PostRenderer, interactWithRemote)
-	rel.Hooks, manifestDoc, rel.Info.Notes, err = i.cfg.renderResources(chrt, valuesToRender, i.ReleaseName, i.OutputDir, i.SubNotes, i.UseReleaseName, i.IncludeCRDs, i.PostRenderer, i.DryRun)
 	// Even for errors, attach this if available
 	if manifestDoc != nil {
 		rel.Manifest = manifestDoc.String()
@@ -301,7 +309,7 @@ func (i *Install) RunWithContext(ctx context.Context, chrt *chart.Chart, vals ma
 	}
 
 	// Bail out here if it is a dry run
-	if i.DryRun != "none" && i.DryRun != "false" {
+	if i.DryRun {
 		rel.Info.Description = "Dry run complete"
 		return rel, nil
 	}
@@ -471,7 +479,7 @@ func (i *Install) availableName() error {
 		return errors.Wrapf(err, "release name %q", start)
 	}
 	// On dry run, bail here
-	if i.DryRun != "none" && i.DryRun != "false" {
+	if i.DryRun {
 		return nil
 	}
 

pkg/action/install_test.go

@@ -234,7 +234,7 @@ func TestInstallRelease_WithChartAndDependencyAllNotes(t *testing.T) {
 func TestInstallRelease_DryRun(t *testing.T) {
 	is := assert.New(t)
 	instAction := installAction(t)
-	instAction.DryRun = "true"
+	instAction.DryRun = true
 	vals := map[string]interface{}{}
 	res, err := instAction.Run(buildChart(withSampleTemplates()), vals)
 	if err != nil {
@@ -258,7 +258,7 @@ func TestInstallRelease_DryRun(t *testing.T) {
 func TestInstallRelease_DryRun_Lookup(t *testing.T) {
 	is := assert.New(t)
 	instAction := installAction(t)
-	instAction.DryRun = "true"
+	instAction.DryRun = true
 	vals := map[string]interface{}{}
 
 	mockChart := buildChart(withSampleTemplates())
@@ -278,7 +278,7 @@ func TestInstallRelease_DryRun_Lookup(t *testing.T) {
 func TestInstallReleaseIncorrectTemplate_DryRun(t *testing.T) {
 	is := assert.New(t)
 	instAction := installAction(t)
-	instAction.DryRun = "true"
+	instAction.DryRun = true
 	vals := map[string]interface{}{}
 	_, err := instAction.Run(buildChart(withSampleIncludingIncorrectTemplates()), vals)
 	expectedErr := "\"hello/templates/incorrect\" at <.Values.bad.doh>: nil pointer evaluating interface {}.doh"

pkg/action/upgrade.go

@@ -70,7 +70,9 @@ type Upgrade struct {
 	// DisableHooks disables hook processing if set to true.
 	DisableHooks bool
 	// DryRun controls whether the operation is prepared, but not executed.
-	DryRun string
+	DryRun bool
+	// DryRunOption controls whether the operation is prepared, but not executed with options on whether or not to interact with the remote cluster.
+	DryRunOption string
 	// Force will, if set to `true`, ignore certain warnings and perform the upgrade anyway.
 	//
 	// This should be used with caution.
@@ -113,8 +115,6 @@ type resultMessage struct {
 func NewUpgrade(cfg *Configuration) *Upgrade {
 	up := &Upgrade{
 		cfg: cfg,
-		// Set default value of DryRun for before flags are binded (tests)
-		DryRun: "none",
 	}
 	up.ChartPathOptions.registryClient = cfg.RegistryClient
 
@@ -140,6 +140,12 @@ func (u *Upgrade) RunWithContext(ctx context.Context, name string, chart *chart.
 	if err := chartutil.ValidateReleaseName(name); err != nil {
 		return nil, errors.Errorf("release name is invalid: %s", name)
 	}
+
+	// determine dry run behavior
+	if u.DryRun || u.DryRunOption == "client" || u.DryRunOption == "server" || u.DryRunOption == "true" {
+		u.DryRun = true
+	}
+
 	u.cfg.Log("preparing upgrade for %s", name)
 	currentRelease, upgradedRelease, err := u.prepareUpgrade(name, chart, vals)
 	if err != nil {
@@ -153,8 +159,9 @@ func (u *Upgrade) RunWithContext(ctx context.Context, name string, chart *chart.
 	if err != nil {
 		return res, err
 	}
+
 	// Do not update for dry runs
-	if u.DryRun == "none" || u.DryRun == "false" {
+	if !u.DryRun {
 		u.cfg.Log("updating status for upgraded release for %s", name)
 		if err := u.cfg.Releases.Update(upgradedRelease); err != nil {
 			return res, err
@@ -232,7 +239,13 @@ func (u *Upgrade) prepareUpgrade(name string, chart *chart.Chart, vals map[strin
 		return nil, nil, err
 	}
 
-	hooks, manifestDoc, notesTxt, err := u.cfg.renderResources(chart, valuesToRender, "", "", u.SubNotes, false, false, u.PostRenderer, u.DryRun)
+	// determine whether or not to interact with remote
+	var interactWithRemote bool
+	if !u.DryRun || u.DryRunOption == "server" {
+		interactWithRemote = true
+	}
+
+	hooks, manifestDoc, notesTxt, err := u.cfg.renderResources(chart, valuesToRender, "", "", u.SubNotes, false, false, u.PostRenderer, interactWithRemote)
 	if err != nil {
 		return nil, nil, err
 	}
@@ -311,7 +324,7 @@ func (u *Upgrade) performUpgrade(ctx context.Context, originalRelease, upgradedR
 	})
 
 	// Run if it is a dry run
-	if u.DryRun != "none" && u.DryRun != "false" {
+	if u.DryRun {
 		u.cfg.Log("dry run for %s", upgradedRelease.Name)
 		if len(u.Description) > 0 {
 			upgradedRelease.Info.Description = u.Description