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

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

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

cmd/helm/install.go

@@ -154,9 +154,8 @@ 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.BoolVar(&client.DryRun, "dry-run", false, "simulate an install")
-	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.StringVar(&client.DryRunOption, "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.Lookup("dry-run").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")
@@ -175,8 +174,6 @@ 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 {

cmd/helm/upgrade.go

@@ -218,9 +218,8 @@ 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.BoolVar(&client.DryRun, "dry-run", false, "simulate an upgrade")
-	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.StringVar(&client.DryRunOption, "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.Lookup("dry-run").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")
@@ -243,8 +242,6 @@ 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/install.go

@@ -210,7 +210,8 @@ func (i *Install) RunWithContext(ctx context.Context, chrt *chart.Chart, vals ma
 	}
 
 	var interactWithRemote bool
-	if !i.DryRun || i.DryRunOption == "server" {
+	//  `helm template` is the only command that Install.APIVersions field will not be nil.
+	if (!i.DryRun || i.DryRunOption == "server") && i.APIVersions == nil {
 		interactWithRemote = true
 	}