In-cluster configs must take flag overrides into account

pkg/client/unversioned/clientcmd/client_config.go

@@ -439,19 +439,46 @@ func (config *DirectClientConfig) getCluster() (clientcmdapi.Cluster, error) {
 }
 
 // inClusterClientConfig makes a config that will work from within a kubernetes cluster container environment.
-type inClusterClientConfig struct{}
+// Can take options overrides for flags explicitly provided to the command inside the cluster container.
+type inClusterClientConfig struct {
+	overrides               *ConfigOverrides
+	inClusterConfigProvider func() (*restclient.Config, error)
+}
 
-var _ ClientConfig = inClusterClientConfig{}
+var _ ClientConfig = &inClusterClientConfig{}
 
-func (inClusterClientConfig) RawConfig() (clientcmdapi.Config, error) {
+func (config *inClusterClientConfig) RawConfig() (clientcmdapi.Config, error) {
 	return clientcmdapi.Config{}, fmt.Errorf("inCluster environment config doesn't support multiple clusters")
 }
 
-func (inClusterClientConfig) ClientConfig() (*restclient.Config, error) {
-	return restclient.InClusterConfig()
+func (config *inClusterClientConfig) ClientConfig() (*restclient.Config, error) {
+	if config.inClusterConfigProvider == nil {
+		config.inClusterConfigProvider = restclient.InClusterConfig
 	}
 
-func (inClusterClientConfig) Namespace() (string, bool, error) {
+	icc, err := config.inClusterConfigProvider()
+	if err != nil {
+		return nil, err
+	}
+
+	// in-cluster configs only takes a host, token, or CA file
+	// if any of them were individually provided, ovewrite anything else
+	if config.overrides != nil {
+		if server := config.overrides.ClusterInfo.Server; len(server) > 0 {
+			icc.Host = server
+		}
+		if token := config.overrides.AuthInfo.Token; len(token) > 0 {
+			icc.BearerToken = token
+		}
+		if certificateAuthorityFile := config.overrides.ClusterInfo.CertificateAuthority; len(certificateAuthorityFile) > 0 {
+			icc.TLSClientConfig.CAFile = certificateAuthorityFile
+		}
+	}
+
+	return icc, err
+}
+
+func (config *inClusterClientConfig) Namespace() (string, bool, error) {
 	// This way assumes you've set the POD_NAMESPACE environment variable using the downward API.
 	// This check has to be done first for backwards compatibility with the way InClusterConfig was originally set up
 	if ns := os.Getenv("POD_NAMESPACE"); ns != "" {
@@ -468,12 +495,12 @@ func (inClusterClientConfig) Namespace() (string, bool, error) {
 	return "default", false, nil
 }
 
-func (inClusterClientConfig) ConfigAccess() ConfigAccess {
+func (config *inClusterClientConfig) ConfigAccess() ConfigAccess {
 	return NewDefaultClientConfigLoadingRules()
 }
 
 // Possible returns true if loading an inside-kubernetes-cluster is possible.
-func (inClusterClientConfig) Possible() bool {
+func (config *inClusterClientConfig) Possible() bool {
 	fi, err := os.Stat("/var/run/secrets/kubernetes.io/serviceaccount/token")
 	return os.Getenv("KUBERNETES_SERVICE_HOST") != "" &&
 		os.Getenv("KUBERNETES_SERVICE_PORT") != "" &&

pkg/client/unversioned/clientcmd/client_config_test.go

@@ -24,6 +24,7 @@ import (
 	"testing"
 
 	"github.com/imdario/mergo"
+	"k8s.io/kubernetes/pkg/client/restclient"
 	clientcmdapi "k8s.io/kubernetes/pkg/client/unversioned/clientcmd/api"
 )
 
@@ -372,6 +373,120 @@ func TestCreateMissingContext(t *testing.T) {
 	}
 }
 
+func TestInClusterClientConfigPrecedence(t *testing.T) {
+	tt := []struct {
+		overrides *ConfigOverrides
+	}{
+		{
+			overrides: &ConfigOverrides{
+				ClusterInfo: clientcmdapi.Cluster{
+					Server: "https://host-from-overrides.com",
+				},
+			},
+		},
+		{
+			overrides: &ConfigOverrides{
+				AuthInfo: clientcmdapi.AuthInfo{
+					Token: "https://host-from-overrides.com",
+				},
+			},
+		},
+		{
+			overrides: &ConfigOverrides{
+				ClusterInfo: clientcmdapi.Cluster{
+					CertificateAuthority: "/path/to/ca-from-overrides.crt",
+				},
+			},
+		},
+		{
+			overrides: &ConfigOverrides{
+				ClusterInfo: clientcmdapi.Cluster{
+					Server: "https://host-from-overrides.com",
+				},
+				AuthInfo: clientcmdapi.AuthInfo{
+					Token: "https://host-from-overrides.com",
+				},
+			},
+		},
+		{
+			overrides: &ConfigOverrides{
+				ClusterInfo: clientcmdapi.Cluster{
+					Server:               "https://host-from-overrides.com",
+					CertificateAuthority: "/path/to/ca-from-overrides.crt",
+				},
+			},
+		},
+		{
+			overrides: &ConfigOverrides{
+				ClusterInfo: clientcmdapi.Cluster{
+					CertificateAuthority: "/path/to/ca-from-overrides.crt",
+				},
+				AuthInfo: clientcmdapi.AuthInfo{
+					Token: "https://host-from-overrides.com",
+				},
+			},
+		},
+		{
+			overrides: &ConfigOverrides{
+				ClusterInfo: clientcmdapi.Cluster{
+					Server:               "https://host-from-overrides.com",
+					CertificateAuthority: "/path/to/ca-from-overrides.crt",
+				},
+				AuthInfo: clientcmdapi.AuthInfo{
+					Token: "https://host-from-overrides.com",
+				},
+			},
+		},
+		{
+			overrides: &ConfigOverrides{},
+		},
+	}
+
+	for _, tc := range tt {
+		expectedServer := "https://host-from-cluster.com"
+		expectedToken := "token-from-cluster"
+		expectedCAFile := "/path/to/ca-from-cluster.crt"
+
+		icc := &inClusterClientConfig{
+			inClusterConfigProvider: func() (*restclient.Config, error) {
+				return &restclient.Config{
+					Host:        expectedServer,
+					BearerToken: expectedToken,
+					TLSClientConfig: restclient.TLSClientConfig{
+						CAFile: expectedCAFile,
+					},
+				}, nil
+			},
+			overrides: tc.overrides,
+		}
+
+		clientConfig, err := icc.ClientConfig()
+		if err != nil {
+			t.Fatalf("Unxpected error: %v", err)
+		}
+
+		if overridenServer := tc.overrides.ClusterInfo.Server; len(overridenServer) > 0 {
+			expectedServer = overridenServer
+		}
+		if overridenToken := tc.overrides.AuthInfo.Token; len(overridenToken) > 0 {
+			expectedToken = overridenToken
+		}
+		if overridenCAFile := tc.overrides.ClusterInfo.CertificateAuthority; len(overridenCAFile) > 0 {
+			expectedCAFile = overridenCAFile
+		}
+
+		if clientConfig.Host != expectedServer {
+			t.Errorf("Expected server %v, got %v", expectedServer, clientConfig.Host)
+		}
+		if clientConfig.BearerToken != expectedToken {
+			t.Errorf("Expected token %v, got %v", expectedToken, clientConfig.BearerToken)
+		}
+		if clientConfig.TLSClientConfig.CAFile != expectedCAFile {
+			t.Errorf("Expected Certificate Authority %v, got %v", expectedCAFile, clientConfig.TLSClientConfig.CAFile)
+		}
+	}
+}
+
 func matchBoolArg(expected, got bool, t *testing.T) {
 	if expected != got {
 		t.Errorf("Expected %v, got %v", expected, got)

pkg/client/unversioned/clientcmd/merged_client_builder.go

@@ -51,12 +51,12 @@ type InClusterConfig interface {
 
 // NewNonInteractiveDeferredLoadingClientConfig creates a ConfigClientClientConfig using the passed context name
 func NewNonInteractiveDeferredLoadingClientConfig(loader ClientConfigLoader, overrides *ConfigOverrides) ClientConfig {
-	return &DeferredLoadingClientConfig{loader: loader, overrides: overrides, icc: inClusterClientConfig{}}
+	return &DeferredLoadingClientConfig{loader: loader, overrides: overrides, icc: &inClusterClientConfig{overrides: overrides}}
 }
 
 // NewInteractiveDeferredLoadingClientConfig creates a ConfigClientClientConfig using the passed context name and the fallback auth reader
 func NewInteractiveDeferredLoadingClientConfig(loader ClientConfigLoader, overrides *ConfigOverrides, fallbackReader io.Reader) ClientConfig {
-	return &DeferredLoadingClientConfig{loader: loader, overrides: overrides, icc: inClusterClientConfig{}, fallbackReader: fallbackReader}
+	return &DeferredLoadingClientConfig{loader: loader, overrides: overrides, icc: &inClusterClientConfig{overrides: overrides}, fallbackReader: fallbackReader}
 }
 
 func (config *DeferredLoadingClientConfig) createClientConfig() (ClientConfig, error) {

pkg/client/unversioned/clientcmd/overrides.go

@@ -126,6 +126,18 @@ const (
 	FlagTimeout      = "request-timeout"
 )
 
+// RecommendedConfigOverrideFlags is a convenience method to return recommended flag names prefixed with a string of your choosing
+func RecommendedConfigOverrideFlags(prefix string) ConfigOverrideFlags {
+	return ConfigOverrideFlags{
+		AuthOverrideFlags:    RecommendedAuthOverrideFlags(prefix),
+		ClusterOverrideFlags: RecommendedClusterOverrideFlags(prefix),
+		ContextOverrideFlags: RecommendedContextOverrideFlags(prefix),
+
+		CurrentContext: FlagInfo{prefix + FlagContext, "", "", "The name of the kubeconfig context to use"},
+		Timeout:        FlagInfo{prefix + FlagTimeout, "", "0", "The length of time to wait before giving up on a single server request. Non-zero values should contain a corresponding time unit (e.g. 1s, 2m, 3h). A value of zero means don't timeout requests."},
+	}
+}
+
 // RecommendedAuthOverrideFlags is a convenience method to return recommended flag names prefixed with a string of your choosing
 func RecommendedAuthOverrideFlags(prefix string) AuthOverrideFlags {
 	return AuthOverrideFlags{
@@ -148,18 +160,6 @@ func RecommendedClusterOverrideFlags(prefix string) ClusterOverrideFlags {
 	}
 }
 
-// RecommendedConfigOverrideFlags is a convenience method to return recommended flag names prefixed with a string of your choosing
-func RecommendedConfigOverrideFlags(prefix string) ConfigOverrideFlags {
-	return ConfigOverrideFlags{
-		AuthOverrideFlags:    RecommendedAuthOverrideFlags(prefix),
-		ClusterOverrideFlags: RecommendedClusterOverrideFlags(prefix),
-		ContextOverrideFlags: RecommendedContextOverrideFlags(prefix),
-
-		CurrentContext: FlagInfo{prefix + FlagContext, "", "", "The name of the kubeconfig context to use"},
-		Timeout:        FlagInfo{prefix + FlagTimeout, "", "0", "The length of time to wait before giving up on a single server request. Non-zero values should contain a corresponding time unit (e.g. 1s, 2m, 3h). A value of zero means don't timeout requests."},
-	}
-}
-
 // RecommendedContextOverrideFlags is a convenience method to return recommended flag names prefixed with a string of your choosing
 func RecommendedContextOverrideFlags(prefix string) ContextOverrideFlags {
 	return ContextOverrideFlags{
@@ -169,6 +169,15 @@ func RecommendedContextOverrideFlags(prefix string) ContextOverrideFlags {
 	}
 }
 
+// BindOverrideFlags is a convenience method to bind the specified flags to their associated variables
+func BindOverrideFlags(overrides *ConfigOverrides, flags *pflag.FlagSet, flagNames ConfigOverrideFlags) {
+	BindAuthInfoFlags(&overrides.AuthInfo, flags, flagNames.AuthOverrideFlags)
+	BindClusterFlags(&overrides.ClusterInfo, flags, flagNames.ClusterOverrideFlags)
+	BindContextFlags(&overrides.Context, flags, flagNames.ContextOverrideFlags)
+	flagNames.CurrentContext.BindStringFlag(flags, &overrides.CurrentContext)
+	flagNames.Timeout.BindStringFlag(flags, &overrides.Timeout)
+}
+
 // BindAuthInfoFlags is a convenience method to bind the specified flags to their associated variables
 func BindAuthInfoFlags(authInfo *clientcmdapi.AuthInfo, flags *pflag.FlagSet, flagNames AuthOverrideFlags) {
 	flagNames.ClientCertificate.BindStringFlag(flags, &authInfo.ClientCertificate)
@@ -189,15 +198,6 @@ func BindClusterFlags(clusterInfo *clientcmdapi.Cluster, flags *pflag.FlagSet, f
 	flagNames.InsecureSkipTLSVerify.BindBoolFlag(flags, &clusterInfo.InsecureSkipTLSVerify)
 }
 
-// BindOverrideFlags is a convenience method to bind the specified flags to their associated variables
-func BindOverrideFlags(overrides *ConfigOverrides, flags *pflag.FlagSet, flagNames ConfigOverrideFlags) {
-	BindAuthInfoFlags(&overrides.AuthInfo, flags, flagNames.AuthOverrideFlags)
-	BindClusterFlags(&overrides.ClusterInfo, flags, flagNames.ClusterOverrideFlags)
-	BindContextFlags(&overrides.Context, flags, flagNames.ContextOverrideFlags)
-	flagNames.CurrentContext.BindStringFlag(flags, &overrides.CurrentContext)
-	flagNames.Timeout.BindStringFlag(flags, &overrides.Timeout)
-}
-
 // BindFlags is a convenience method to bind the specified flags to their associated variables
 func BindContextFlags(contextInfo *clientcmdapi.Context, flags *pflag.FlagSet, flagNames ContextOverrideFlags) {
 	flagNames.ClusterName.BindStringFlag(flags, &contextInfo.Cluster)

test/e2e/kubectl.go

@@ -564,6 +564,48 @@ var _ = framework.KubeDescribe("Kubectl client", func() {
 				framework.Failf("Container port output missing expected value. Wanted:'%s', got: %s", nginxDefaultOutput, body)
 			}
 		})
+
+		It("should handle in-cluster config", func() {
+			By("overriding icc with values provided by flags")
+			kubectlPath := framework.TestContext.KubectlPath
+
+			inClusterHost := strings.TrimSpace(framework.RunHostCmdOrDie(ns, simplePodName, "printenv KUBERNETES_SERVICE_HOST"))
+			inClusterPort := strings.TrimSpace(framework.RunHostCmdOrDie(ns, simplePodName, "printenv KUBERNETES_SERVICE_PORT"))
+			framework.RunKubectlOrDie("cp", kubectlPath, ns+"/"+simplePodName+":/")
+
+			By("getting pods with in-cluster configs")
+			execOutput := framework.RunHostCmdOrDie(ns, simplePodName, "/kubectl get pods")
+			if matched, err := regexp.MatchString("nginx +1/1 +Running", execOutput); err != nil || !matched {
+				framework.Failf("Unexpected kubectl exec output: ", execOutput)
+			}
+
+			By("trying to use kubectl with invalid token")
+			_, err := framework.RunHostCmd(ns, simplePodName, "/kubectl get pods --token=invalid --v=7 2>&1")
+			framework.Logf("got err %v", err)
+			Expect(err).To(HaveOccurred())
+			Expect(err).To(ContainSubstring("User \"system:anonymous\" cannot list pods in the namespace"))
+			Expect(err).To(ContainSubstring("Using in-cluster namespace"))
+			Expect(err).To(ContainSubstring("Using in-cluster configuration"))
+			Expect(err).To(ContainSubstring("Authorization: Bearer invalid"))
+			Expect(err).To(ContainSubstring("Response Status: 403 Forbidden"))
+
+			By("trying to use kubectl with invalid server")
+			_, err = framework.RunHostCmd(ns, simplePodName, "/kubectl get pods --server=invalid --v=6 2>&1")
+			framework.Logf("got err %v", err)
+			Expect(err).To(HaveOccurred())
+			Expect(err).To(ContainSubstring("Unable to connect to the server"))
+			Expect(err).To(ContainSubstring("GET http://invalid/api"))
+
+			By("trying to use kubectl with invalid namespace")
+			output, _ := framework.RunHostCmd(ns, simplePodName, "/kubectl get pods --namespace=invalid --v=6 2>&1")
+			Expect(output).To(ContainSubstring("No resources found"))
+			Expect(output).ToNot(ContainSubstring("Using in-cluster namespace"))
+			Expect(output).To(ContainSubstring("Using in-cluster configuration"))
+			if matched, _ := regexp.MatchString(fmt.Sprintf("GET http[s]?://%s:%s/api/v1/namespaces/invalid/pods", inClusterHost, inClusterPort), output); !matched {
+				framework.Failf("Unexpected kubectl exec output: ", output)
+			}
+
+		})
 	})
 
 	framework.KubeDescribe("Kubectl api-versions", func() {