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

@@ -262,7 +262,7 @@ func runInstall(args []string, client *action.Install, valueOpts *values.Options
 
 	client.Namespace = settings.Namespace()
 
-	// validate dry-run-option flag value is one of the allowed values
+	// Validate DryRunOption member is one of the allowed values
 	if err := validateDryRunOptionFlag(client.DryRunOption); err != nil {
 		return nil, err
 	}
@@ -309,7 +309,7 @@ func compInstall(args []string, toComplete string, client *action.Install) ([]st
 }
 
 func validateDryRunOptionFlag(dryRunOptionFlagValue string) error {
-	// validate dry-run-option flag value with set of allowed value
+	// Validate dry-run flag value with a set of allowed value
 	allowedDryRunValues := []string{"false", "true", "none", "client", "server"}
 	isAllowed := false
 	for _, v := range allowedDryRunValues {
@@ -319,7 +319,7 @@ func validateDryRunOptionFlag(dryRunOptionFlagValue string) error {
 		}
 	}
 	if !isAllowed {
-		return errors.New("Invalid dry-run flag. Flag must one of the following: false, true, none, client, sever")
+		return errors.New("Invalid dry-run flag. Flag must one of the following: false, true, none, client, server")
 	}
 	return nil
 }

cmd/helm/upgrade.go

@@ -139,7 +139,7 @@ func newUpgradeCmd(cfg *action.Configuration, out io.Writer) *cobra.Command {
 			if err != nil {
 				return err
 			}
-			// validate dry-run flag value is one of the allowed values
+			// Validate dry-run flag value is one of the allowed values
 			if err := validateDryRunOptionFlag(client.DryRunOption); err != nil {
 				return err
 			}

pkg/action/action.go

@@ -120,11 +120,9 @@ func (cfg *Configuration) renderResources(ch *chart.Chart, values chartutil.Valu
 	var files map[string]string
 	var err2 error
 
-	// A `helm template`  should not talk to the remote cluster. However, commands
-	// with the flag `--dry-run-option` with the value of false, none, or sever
-	// 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.
+	// A `helm template` should not talk to the remote cluster. However, commands with the flag
+	//`--dry-run` with the value of `false`, `none`, or `server` should try to interact with the cluster.
+	// It may break in interesting and exotic ways because other data (e.g. discovery) is mocked.
 	if interactWithRemote && cfg.RESTClientGetter != nil {
 		restConfig, err := cfg.RESTClientGetter.ToRESTConfig()
 		if err != nil {

pkg/action/install.go

@@ -204,13 +204,12 @@ func (i *Install) RunWithContext(ctx context.Context, chrt *chart.Chart, vals ma
 		return nil, err
 	}
 
-	// determine dry run behavior
+	// Determine dry run behavior
 	if i.DryRun || i.DryRunOption == "client" || i.DryRunOption == "server" || i.DryRunOption == "true" {
 		i.DryRun = true
 	}
 
 	var interactWithRemote bool
-	//  `helm template` is the only command that Install.APIVersions field will not be nil.
 	if !i.DryRun || i.DryRunOption == "server" {
 		interactWithRemote = true
 	}

pkg/action/upgrade.go

@@ -141,7 +141,7 @@ func (u *Upgrade) RunWithContext(ctx context.Context, name string, chart *chart.
 		return nil, errors.Errorf("release name is invalid: %s", name)
 	}
 
-	// determine dry run behavior
+	// Determine dry run behavior
 	if u.DryRun || u.DryRunOption == "client" || u.DryRunOption == "server" || u.DryRunOption == "true" {
 		u.DryRun = true
 	}
@@ -239,7 +239,7 @@ func (u *Upgrade) prepareUpgrade(name string, chart *chart.Chart, vals map[strin
 		return nil, nil, err
 	}
 
-	// determine whether or not to interact with remote
+	// Determine whether or not to interact with remote
 	var interactWithRemote bool
 	if !u.DryRun || u.DryRunOption == "server" {
 		interactWithRemote = true