kubectl: Validate flag usage against generators

This commit moves the generators into separate buckets and creates
separate calls for each one group. This helps in providing just the
necessary generators to each generator command.

Validation of flags against generators is also added so that flags
that are not meant to be used with a specific generator will result
in error.

pkg/kubectl/cmd/util/factory.go

@@ -57,9 +57,8 @@ const (
 // TODO: pass the various interfaces on the factory directly into the command constructors (so the
 // commands are decoupled from the factory).
 type Factory struct {
-	clients    *ClientCache
-	flags      *pflag.FlagSet
-	generators map[string]kubectl.Generator
+	clients *ClientCache
+	flags   *pflag.FlagSet
 
 	// Returns interfaces for dealing with arbitrary runtime.Objects.
 	Object func() (meta.RESTMapper, runtime.ObjectTyper)
@@ -92,8 +91,8 @@ type Factory struct {
 	// other namespace is specified and whether the namespace was
 	// overriden.
 	DefaultNamespace func() (string, bool, error)
-	// Returns the generator for the provided generator name
-	Generator func(name string) (kubectl.Generator, bool)
+	// Generators returns the generators for the provided command
+	Generators func(cmdName string) map[string]kubectl.Generator
 	// Check whether the kind of resources could be exposed
 	CanBeExposed func(kind unversioned.GroupKind) error
 	// Check whether the kind of resources could be autoscaled
@@ -120,19 +119,31 @@ const (
 )
 
 // DefaultGenerators returns the set of default generators for use in Factory instances
-func DefaultGenerators() map[string]kubectl.Generator {
-	return map[string]kubectl.Generator{
-		RunV1GeneratorName:                          kubectl.BasicReplicationController{},
-		RunPodV1GeneratorName:                       kubectl.BasicPod{},
-		ServiceV1GeneratorName:                      kubectl.ServiceGeneratorV1{},
-		ServiceV2GeneratorName:                      kubectl.ServiceGeneratorV2{},
-		HorizontalPodAutoscalerV1Beta1GeneratorName: kubectl.HorizontalPodAutoscalerV1Beta1{},
-		DeploymentV1Beta1GeneratorName:              kubectl.DeploymentV1Beta1{},
-		JobV1Beta1GeneratorName:                     kubectl.JobV1Beta1{},
-		NamespaceV1GeneratorName:                    kubectl.NamespaceGeneratorV1{},
-		SecretV1GeneratorName:                       kubectl.SecretGeneratorV1{},
-		SecretForDockerRegistryV1GeneratorName:      kubectl.SecretForDockerRegistryGeneratorV1{},
+func DefaultGenerators(cmdName string) map[string]kubectl.Generator {
+	generators := map[string]map[string]kubectl.Generator{}
+	generators["expose"] = map[string]kubectl.Generator{
+		ServiceV1GeneratorName: kubectl.ServiceGeneratorV1{},
+		ServiceV2GeneratorName: kubectl.ServiceGeneratorV2{},
 	}
+	generators["run"] = map[string]kubectl.Generator{
+		RunV1GeneratorName:             kubectl.BasicReplicationController{},
+		RunPodV1GeneratorName:          kubectl.BasicPod{},
+		DeploymentV1Beta1GeneratorName: kubectl.DeploymentV1Beta1{},
+		JobV1Beta1GeneratorName:        kubectl.JobV1Beta1{},
+	}
+	generators["autoscale"] = map[string]kubectl.Generator{
+		HorizontalPodAutoscalerV1Beta1GeneratorName: kubectl.HorizontalPodAutoscalerV1Beta1{},
+	}
+	generators["namespace"] = map[string]kubectl.Generator{
+		NamespaceV1GeneratorName: kubectl.NamespaceGeneratorV1{},
+	}
+	generators["secret"] = map[string]kubectl.Generator{
+		SecretV1GeneratorName: kubectl.SecretGeneratorV1{},
+	}
+	generators["secret-for-docker-registry"] = map[string]kubectl.Generator{
+		SecretForDockerRegistryV1GeneratorName: kubectl.SecretForDockerRegistryGeneratorV1{},
+	}
+	return generators[cmdName]
 }
 
 // NewFactory creates a factory with the default Kubernetes resources defined
@@ -144,8 +155,6 @@ func NewFactory(optionalClientConfig clientcmd.ClientConfig) *Factory {
 	flags := pflag.NewFlagSet("", pflag.ContinueOnError)
 	flags.SetNormalizeFunc(util.WarnWordSepNormalizeFunc) // Warn for "_" flags
 
-	generators := DefaultGenerators()
-
 	clientConfig := optionalClientConfig
 	if optionalClientConfig == nil {
 		clientConfig = DefaultClientConfig(flags)
@@ -154,9 +163,8 @@ func NewFactory(optionalClientConfig clientcmd.ClientConfig) *Factory {
 	clients := NewClientCache(clientConfig)
 
 	return &Factory{
-		clients:    clients,
-		flags:      flags,
-		generators: generators,
+		clients: clients,
+		flags:   flags,
 
 		Object: func() (meta.RESTMapper, runtime.ObjectTyper) {
 			cfg, err := clientConfig.ClientConfig()
@@ -311,9 +319,8 @@ func NewFactory(optionalClientConfig clientcmd.ClientConfig) *Factory {
 		DefaultNamespace: func() (string, bool, error) {
 			return clientConfig.Namespace()
 		},
-		Generator: func(name string) (kubectl.Generator, bool) {
-			generator, ok := generators[name]
-			return generator, ok
+		Generators: func(cmdName string) map[string]kubectl.Generator {
+			return DefaultGenerators(cmdName)
 		},
 		CanBeExposed: func(kind unversioned.GroupKind) error {
 			switch kind {