allow any number of kubeconfig files

pkg/client/clientcmd/loader.go

@@ -33,31 +33,35 @@ import (
 const (
 	RecommendedConfigPathFlag   = "kubeconfig"
 	RecommendedConfigPathEnvVar = "KUBECONFIG"
+
+	DefaultEnvVarIndex     = 0
+	DefaultCurrentDirIndex = 1
+	DefaultHomeDirIndex    = 2
 )
 
-// ClientConfigLoadingRules is a struct that calls our specific locations that are used for merging together a Config
+// ClientConfigLoadingRules is an ExplicitPath and string slice of specific locations that are used for merging together a Config
+// Callers can put the chain together however they want, but we'd recommend:
+// [0] = EnvVarPath
+// [1] = CurrentDirectoryPath
+// [2] = HomeDirectoryPath
+// ExplicitPath is special, because if a user specifically requests a certain file be used and error is reported if thie file is not present
 type ClientConfigLoadingRules struct {
-	CommandLinePath      string
+	ExplicitPath string
-	EnvVarPath           string
+	Precedence   []string
-	CurrentDirectoryPath string
-	HomeDirectoryPath    string
 }
 
-// NewClientConfigLoadingRules returns a ClientConfigLoadingRules object with default fields filled in.  You are not required to
+// NewDefaultClientConfigLoadingRules returns a ClientConfigLoadingRules object with default fields filled in.  You are not required to
 // use this constructor
-func NewClientConfigLoadingRules() *ClientConfigLoadingRules {
+func NewDefaultClientConfigLoadingRules() *ClientConfigLoadingRules {
 	return &ClientConfigLoadingRules{
-		CurrentDirectoryPath: ".kubeconfig",
+		Precedence: []string{os.Getenv(RecommendedConfigPathEnvVar), ".kubeconfig", os.Getenv("HOME") + "/.kube/.kubeconfig"},
-		HomeDirectoryPath:    os.Getenv("HOME") + "/.kube/.kubeconfig",
 	}
 }
 
 // Load takes the loading rules and merges together a Config object based on following order.
-//   1.  CommandLinePath
+//   1.  ExplicitPath
-//   2.  EnvVarPath
+//   2.  Precedence slice
-//   3.  CurrentDirectoryPath
+// A missing ExplicitPath file produces an error. Empty filenames or other missing files are ignored.
-//   4.  HomeDirectoryPath
-// A missing CommandLinePath file produces an error. Empty filenames or other missing files are ignored.
 // Read errors or files with non-deserializable content produce errors.
 // The first file to set a particular map key wins and map key's value is never changed.
 // BUT, if you set a struct value that is NOT contained inside of map, the value WILL be changed.
@@ -71,13 +75,14 @@ func (rules *ClientConfigLoadingRules) Load() (*clientcmdapi.Config, error) {
 	errlist := []error{}
 
 	// Make sure a file we were explicitly told to use exists
-	if len(rules.CommandLinePath) > 0 {
+	if len(rules.ExplicitPath) > 0 {
-		if _, err := os.Stat(rules.CommandLinePath); os.IsNotExist(err) {
+		if _, err := os.Stat(rules.ExplicitPath); os.IsNotExist(err) {
-			errlist = append(errlist, fmt.Errorf("The config file %v does not exist", rules.CommandLinePath))
+			errlist = append(errlist, fmt.Errorf("The config file %v does not exist", rules.ExplicitPath))
 		}
 	}
 
-	kubeConfigFiles := []string{rules.CommandLinePath, rules.EnvVarPath, rules.CurrentDirectoryPath, rules.HomeDirectoryPath}
+	kubeConfigFiles := []string{rules.ExplicitPath}
+	kubeConfigFiles = append(kubeConfigFiles, rules.Precedence...)
 
 	// first merge all of our maps
 	mapConfig := clientcmdapi.NewConfig()
@@ -85,7 +90,7 @@ func (rules *ClientConfigLoadingRules) Load() (*clientcmdapi.Config, error) {
 		if err := mergeConfigWithFile(mapConfig, file); err != nil {
 			errlist = append(errlist, err)
 		}
-		if err := resolveLocalPaths(file, mapConfig); err != nil {
+		if err := ResolveLocalPaths(file, mapConfig); err != nil {
 			errlist = append(errlist, err)
 		}
 	}
@@ -96,7 +101,7 @@ func (rules *ClientConfigLoadingRules) Load() (*clientcmdapi.Config, error) {
 	for i := len(kubeConfigFiles) - 1; i >= 0; i-- {
 		file := kubeConfigFiles[i]
 		mergeConfigWithFile(nonMapConfig, file)
-		resolveLocalPaths(file, nonMapConfig)
+		ResolveLocalPaths(file, nonMapConfig)
 	}
 
 	// since values are overwritten, but maps values are not, we can merge the non-map config on top of the map config and
@@ -127,10 +132,10 @@ func mergeConfigWithFile(startingConfig *clientcmdapi.Config, filename string) e
 	return nil
 }
 
-// resolveLocalPaths resolves all relative paths in the config object with respect to the parent directory of the filename
+// ResolveLocalPaths resolves all relative paths in the config object with respect to the parent directory of the filename
 // this cannot be done directly inside of LoadFromFile because doing so there would make it impossible to load a file without
 // modification of its contents.
-func resolveLocalPaths(filename string, config *clientcmdapi.Config) error {
+func ResolveLocalPaths(filename string, config *clientcmdapi.Config) error {
 	if len(filename) == 0 {
 		return nil
 	}

pkg/client/clientcmd/loader_test.go

@@ -78,7 +78,7 @@ var (
 
 func TestNonExistentCommandLineFile(t *testing.T) {
 	loadingRules := ClientConfigLoadingRules{
-		CommandLinePath: "bogus_file",
+		ExplicitPath: "bogus_file",
 	}
 
 	_, err := loadingRules.Load()
@@ -92,9 +92,7 @@ func TestNonExistentCommandLineFile(t *testing.T) {
 
 func TestToleratingMissingFiles(t *testing.T) {
 	loadingRules := ClientConfigLoadingRules{
-		EnvVarPath:           "bogus1",
+		Precedence: []string{"bogus1", "bogus2", "bogus3"},
-		CurrentDirectoryPath: "bogus2",
-		HomeDirectoryPath:    "bogus3",
 	}
 
 	_, err := loadingRules.Load()
@@ -112,7 +110,7 @@ func TestErrorReadingFile(t *testing.T) {
 	}
 
 	loadingRules := ClientConfigLoadingRules{
-		CommandLinePath: commandLineFile.Name(),
+		ExplicitPath: commandLineFile.Name(),
 	}
 
 	_, err := loadingRules.Load()
@@ -132,7 +130,7 @@ func TestErrorReadingNonFile(t *testing.T) {
 	defer os.Remove(tmpdir)
 
 	loadingRules := ClientConfigLoadingRules{
-		CommandLinePath: tmpdir,
+		ExplicitPath: tmpdir,
 	}
 
 	_, err = loadingRules.Load()
@@ -161,8 +159,8 @@ func TestConflictingCurrentContext(t *testing.T) {
 	WriteToFile(mockEnvVarConfig, envVarFile.Name())
 
 	loadingRules := ClientConfigLoadingRules{
-		CommandLinePath: commandLineFile.Name(),
+		ExplicitPath: commandLineFile.Name(),
-		EnvVarPath:      envVarFile.Name(),
+		Precedence:   []string{envVarFile.Name()},
 	}
 
 	mergedConfig, err := loadingRules.Load()
@@ -211,8 +209,8 @@ func TestResolveRelativePaths(t *testing.T) {
 	WriteToFile(pathResolutionConfig2, configFile2)
 
 	loadingRules := ClientConfigLoadingRules{
-		CommandLinePath: configFile1,
+		ExplicitPath: configFile1,
-		EnvVarPath:      configFile2,
+		Precedence:   []string{configFile2},
 	}
 
 	mergedConfig, err := loadingRules.Load()
@@ -286,8 +284,8 @@ func ExampleMergingSomeWithConflict() {
 	WriteToFile(testConfigConflictAlfa, envVarFile.Name())
 
 	loadingRules := ClientConfigLoadingRules{
-		CommandLinePath: commandLineFile.Name(),
+		ExplicitPath: commandLineFile.Name(),
-		EnvVarPath:      envVarFile.Name(),
+		Precedence:   []string{envVarFile.Name()},
 	}
 
 	mergedConfig, err := loadingRules.Load()
@@ -346,10 +344,8 @@ func ExampleMergingEverythingNoConflicts() {
 	WriteToFile(testConfigDelta, homeDirFile.Name())
 
 	loadingRules := ClientConfigLoadingRules{
-		CommandLinePath:      commandLineFile.Name(),
+		ExplicitPath: commandLineFile.Name(),
-		EnvVarPath:           envVarFile.Name(),
+		Precedence:   []string{envVarFile.Name(), currentDirFile.Name(), homeDirFile.Name()},
-		CurrentDirectoryPath: currentDirFile.Name(),
-		HomeDirectoryPath:    homeDirFile.Name(),
 	}
 
 	mergedConfig, err := loadingRules.Load()

pkg/client/clientcmd/merged_client_builder_test.go

@@ -78,11 +78,11 @@ func testWriteAuthInfoFile(auth clientauth.Info, filename string) error {
 }
 
 func testBindClientConfig(cmd *cobra.Command) ClientConfig {
-	loadingRules := NewClientConfigLoadingRules()
+	loadingRules := NewDefaultClientConfigLoadingRules()
-	loadingRules.EnvVarPath = ""
+	loadingRules.Precedence[DefaultEnvVarIndex] = ""
-	loadingRules.HomeDirectoryPath = ""
+	loadingRules.Precedence[DefaultCurrentDirIndex] = ""
-	loadingRules.CurrentDirectoryPath = ""
+	loadingRules.Precedence[DefaultHomeDirIndex] = ""
-	cmd.PersistentFlags().StringVar(&loadingRules.CommandLinePath, "kubeconfig", "", "Path to the kubeconfig file to use for CLI requests.")
+	cmd.PersistentFlags().StringVar(&loadingRules.ExplicitPath, "kubeconfig", "", "Path to the kubeconfig file to use for CLI requests.")
 
 	overrides := &ConfigOverrides{}
 	BindOverrideFlags(overrides, cmd.PersistentFlags(), RecommendedConfigOverrideFlags(""))

pkg/kubectl/cmd/cmd.go

@@ -314,9 +314,8 @@ func (f *Factory) ClientMapperForCommand(cmd *cobra.Command) resource.ClientMapp
 //           3.  If the command line specifies one and the auth info specifies another, honor the command line technique.
 //   2.  Use default values and potentially prompt for auth information
 func DefaultClientConfig(flags *pflag.FlagSet) clientcmd.ClientConfig {
-	loadingRules := clientcmd.NewClientConfigLoadingRules()
+	loadingRules := clientcmd.NewDefaultClientConfigLoadingRules()
-	loadingRules.EnvVarPath = os.Getenv(clientcmd.RecommendedConfigPathEnvVar)
+	flags.StringVar(&loadingRules.ExplicitPath, "kubeconfig", "", "Path to the kubeconfig file to use for CLI requests.")
-	flags.StringVar(&loadingRules.CommandLinePath, "kubeconfig", "", "Path to the kubeconfig file to use for CLI requests.")
 
 	overrides := &clientcmd.ConfigOverrides{}
 	flagNames := clientcmd.RecommendedConfigOverrideFlags("")

pkg/kubectl/cmd/config/view.go

@@ -19,7 +19,6 @@ package config
 import (
 	"fmt"
 	"io"
-	"os"
 
 	"github.com/golang/glog"
 	"github.com/spf13/cobra"
@@ -113,9 +112,8 @@ func (o viewOptions) validate() error {
 func (o *viewOptions) getStartingConfig() (*clientcmdapi.Config, string, error) {
 	switch {
 	case o.merge.Value():
-		loadingRules := clientcmd.NewClientConfigLoadingRules()
+		loadingRules := clientcmd.NewDefaultClientConfigLoadingRules()
-		loadingRules.EnvVarPath = os.Getenv("KUBECONFIG")
+		loadingRules.ExplicitPath = o.pathOptions.specifiedFile
-		loadingRules.CommandLinePath = o.pathOptions.specifiedFile
 
 		overrides := &clientcmd.ConfigOverrides{}
 		clientConfig := clientcmd.NewNonInteractiveDeferredLoadingClientConfig(loadingRules, overrides)