k8s.io/client-go: add ClientConfig option to override raw config

staging/src/k8s.io/client-go/tools/clientcmd/client_config.go

@@ -115,6 +115,19 @@ func NewClientConfigFromBytes(configBytes []byte) (ClientConfig, error) {
 	return &DirectClientConfig{*config, "", &ConfigOverrides{}, nil, nil, promptedCredentials{}}, nil
 }
 
+// NewClientConfigWithMergedRawConfig acts like a NewDefaultClientConfig but merges the RawConfig with the overrides
+func NewClientConfigWithMergedRawConfig(config clientcmdapi.Config, overrides *ConfigOverrides) (ClientConfig, error) {
+	clientCfg := &DirectClientConfig{config, config.CurrentContext, overrides, nil, NewDefaultClientConfigLoadingRules(), promptedCredentials{}}
+
+	mergedRawCfg, err := clientCfg.getMergedRawConfig()
+	clientCfg.config = mergedRawCfg
+	if err != nil {
+		return nil, err
+	}
+	return clientCfg, nil
+
+}
+
 // RESTConfigFromKubeConfig is a convenience method to give back a restconfig from your kubeconfig bytes.
 // For programmatic access, this is what you want 80% of the time
 func RESTConfigFromKubeConfig(configBytes []byte) (*restclient.Config, error) {
@@ -129,6 +142,40 @@ func (config *DirectClientConfig) RawConfig() (clientcmdapi.Config, error) {
 	return config.config, nil
 }
 
+// getMergedRawConfig returns the raw kube config merged with the overrides
+func (config *DirectClientConfig) getMergedRawConfig() (clientcmdapi.Config, error) {
+	if err := config.ConfirmUsable(); err != nil {
+		return clientcmdapi.Config{}, err
+	}
+	merged := clientcmdapi.NewConfig()
+
+	// set the AuthInfo merged with overrides in the merged config
+	mergedAuthInfo, err := config.getAuthInfo()
+	if err != nil {
+		return clientcmdapi.Config{}, err
+	}
+	mergedAuthInfoName, _ := config.getAuthInfoName()
+	merged.AuthInfos[mergedAuthInfoName] = &mergedAuthInfo
+
+	// set the Context merged with overrides in the merged config
+	mergedContext, err := config.getContext()
+	if err != nil {
+		return clientcmdapi.Config{}, err
+	}
+	mergedContextName, _ := config.getContextName()
+	merged.Contexts[mergedContextName] = &mergedContext
+	merged.CurrentContext = mergedContextName
+
+	// set the Cluster merged with overrides in the merged config
+	configClusterInfo, err := config.getCluster()
+	if err != nil {
+		return clientcmdapi.Config{}, err
+	}
+	configClusterName, _ := config.getClusterName()
+	merged.Clusters[configClusterName] = &configClusterInfo
+	return *merged, nil
+}
+
 // ClientConfig implements ClientConfig
 func (config *DirectClientConfig) ClientConfig() (*restclient.Config, error) {
 	// check that getAuthInfo, getContext, and getCluster do not return an error.

staging/src/k8s.io/client-go/tools/clientcmd/client_config_test.go

@@ -1013,3 +1013,72 @@ func TestCleanANSIEscapeCodes(t *testing.T) {
 		})
 	}
 }
+
+func TestMergeRawConfigDoOverride(t *testing.T) {
+	cfg := createValidTestConfig()
+
+	overrides := &ConfigOverrides{
+		ClusterInfo: clientcmdapi.Cluster{
+			Server: "http://localhost:8081",
+		},
+		Context: clientcmdapi.Context{
+			Namespace: "foobar",
+			Cluster:   "clean",
+			AuthInfo:  "clean",
+		},
+		AuthInfo: clientcmdapi.AuthInfo{
+			Token: "modified-token",
+		},
+		CurrentContext: "clean",
+	}
+
+	cut, err := NewClientConfigWithMergedRawConfig(*cfg, overrides)
+	if err != nil {
+		t.Fatalf("Unexpected error: %v", err)
+	}
+	act, err := cut.RawConfig()
+	if err != nil {
+		t.Fatalf("Unexpected error: %v", err)
+	}
+
+	if act.Clusters["clean"].Server != "http://localhost:8081" {
+		t.Errorf("Expected server %v, got %v", "http://localhost:8081", act.Clusters["clean"].Server)
+	}
+
+	if act.Contexts["clean"].Namespace != "foobar" {
+		t.Errorf("Expected namespace %v, got %v", "foobar", act.Contexts["clean"].Namespace)
+	}
+}
+
+func TestMergeRawConfigDoNotOverride(t *testing.T) {
+	cfg := createValidTestConfig()
+
+	overrides := &ConfigOverrides{
+		ClusterInfo: clientcmdapi.Cluster{
+			Server: "http://localhost:8081",
+		},
+		Context: clientcmdapi.Context{
+			Namespace: "foobar",
+			Cluster:   "clean",
+			AuthInfo:  "clean",
+		},
+		AuthInfo: clientcmdapi.AuthInfo{
+			Token: "modified-token",
+		},
+		CurrentContext: "clean",
+	}
+
+	cut := NewDefaultClientConfig(*cfg, overrides)
+	act, err := cut.RawConfig()
+	if err != nil {
+		t.Fatalf("Unexpected error: %v", err)
+	}
+
+	if act.Clusters["clean"].Server != cfg.Clusters["clean"].Server {
+		t.Errorf("Expected server %v, got %v", cfg.Clusters["clean"].Server, act.Clusters["clean"].Server)
+	}
+
+	if act.Contexts["clean"].Namespace != cfg.Contexts["clean"].Namespace {
+		t.Errorf("Expected namespace %v, got %v", cfg.Contexts["clean"].Namespace, act.Contexts["clean"].Namespace)
+	}
+}