Support multiple Kubeconfig files

cmd/devserver/main.go

@@ -12,20 +12,29 @@ import (
 )
 
 var (
-	debug      = flag.Bool("debug", false, "Enable debug mode.")
-	kubeconfig = flag.String("kubeconfig", "", "Optional Kubeconfig file.")
-	sync       = flag.Bool("sync", false, "Sync the changes from kubenav with the used Kubeconfig file.")
+	debugFlag             = flag.Bool("debug", false, "Enable debug mode.")
+	kubeconfigFlag        = flag.String("kubeconfig", "", "Optional Kubeconfig file.")
+	kubeconfigIncludeFlag = flag.String("kubeconfig-include", "", "Comma separated list of globs to include in the Kubeconfig. When this option is used the '-kubeconfig' and '-sync' flag is ignored.")
+	kubeconfigExcludeFlag = flag.String("kubeconfig-exclude", "", "Comma separated list of globs to exclude from the Kubeconfig. This flag must be used in combination with the '-kubeconfig-include' flag.")
+	syncFlag              = flag.Bool("sync", false, "Sync the changes from kubenav with the used Kubeconfig file.")
 )
 
 func main() {
 	// Parse command-line flags.
+	// When the "-kubeconfig-includ" flag is used the sync flag is ignored. Therefor we set the sync value always to
+	// false. The same applies for the "-kubeconfig" flag, but this is handled by the Kubernetes client.
 	flag.Parse()
 
+	sync := *syncFlag
+	if *kubeconfigIncludeFlag != "" {
+		sync = false
+	}
+
 	// Setup the logger and print the version information.
 	log := logrus.StandardLogger()
 
 	logLevel := logrus.InfoLevel
-	if *debug {
+	if *debugFlag {
 		logLevel = logrus.DebugLevel
 	}
 
@@ -34,14 +43,14 @@ func main() {
 	log.Infof(version.BuildContext())
 
 	// Create the client for the interaction with the Kubernetes API.
-	client, err := kube.NewClient(*kubeconfig)
+	client, err := kube.NewClient(*kubeconfigFlag, *kubeconfigIncludeFlag, *kubeconfigExcludeFlag)
 	if err != nil {
 		log.WithError(err).Fatalf("Could not create Kubernetes client")
 	}
 
 	// Register the API for the Electron app and start the server.
 	router := http.NewServeMux()
-	electron.Register(router, *sync, client)
+	electron.Register(router, sync, client)
 
 	if err := http.ListenAndServe(":14122", router); err != nil {
 		log.WithError(err).Fatalf("kubenav server died")

cmd/electron/main.go

@@ -25,9 +25,11 @@ var (
 )
 
 var (
-	debug      = flag.Bool("debug", false, "Enable debug mode.")
-	kubeconfig = flag.String("kubeconfig", "", "Optional Kubeconfig file.")
-	sync       = flag.Bool("sync", false, "Sync the changes from kubenav with the used Kubeconfig file.")
+	debugFlag             = flag.Bool("debug", false, "Enable debug mode.")
+	kubeconfigFlag        = flag.String("kubeconfig", "", "Optional Kubeconfig file.")
+	kubeconfigIncludeFlag = flag.String("kubeconfig-include", "", "Comma separated list of globs to include in the Kubeconfig. When this option is used the '-kubeconfig' and '-sync' flag is ignored.")
+	kubeconfigExcludeFlag = flag.String("kubeconfig-exclude", "", "Comma separated list of globs to exclude from the Kubeconfig. This flag must be used in combination with the '-kubeconfig-include' flag.")
+	syncFlag              = flag.Bool("sync", false, "Sync the changes from kubenav with the used Kubeconfig file.")
 )
 
 // Message is the structure of a Server Sent Event, which contains the Event and Data. Server Sent Events are used to
@@ -41,13 +43,20 @@ var messageChannel = make(chan Message)
 
 func main() {
 	// Parse command-line flags.
+	// When the "-kubeconfig-includ" flag is used the sync flag is ignored. Therefor we set the sync value always to
+	// false. The same applies for the "-kubeconfig" flag, but this is handled by the Kubernetes client.
 	flag.Parse()
 
+	sync := *syncFlag
+	if *kubeconfigIncludeFlag != "" {
+		sync = false
+	}
+
 	// Setup the logger and print the version information.
 	log := logrus.StandardLogger()
 
 	logLevel := logrus.InfoLevel
-	if *debug {
+	if *debugFlag {
 		logLevel = logrus.DebugLevel
 	}
 
@@ -56,7 +65,7 @@ func main() {
 	log.Infof(version.BuildContext())
 
 	// Create the client for the interaction with the Kubernetes API.
-	client, err := kube.NewClient(*kubeconfig)
+	client, err := kube.NewClient(*kubeconfigFlag, *kubeconfigIncludeFlag, *kubeconfigExcludeFlag)
 	if err != nil {
 		log.WithError(err).Fatalf("Could not create Kubernetes client")
 	}
@@ -66,7 +75,7 @@ func main() {
 	// frontend from the embedded assets.
 	go func() {
 		router := http.NewServeMux()
-		electron.Register(router, *sync, client)
+		electron.Register(router, sync, client)
 
 		// Add route for Server Sent Events. The events are handled via the message channel. Possible events are
 		// "navigation" and "cluster". These events are handled by the frontend to navigate to another page or to modify
@@ -128,7 +137,7 @@ func main() {
 	// selected context back to the Kubeconfig file, the result from the version check and the Kubernetes client and
 	// logger.
 	updateAvailable := checkVersion(version.Version, log)
-	menuOptions, err := getMenuOptions(*sync, updateAvailable, client, log)
+	menuOptions, err := getMenuOptions(sync, updateAvailable, client, log)
 	if err != nil {
 		log.WithError(err).Fatalf("Could not create menu")
 	}
@@ -145,7 +154,7 @@ func main() {
 			VersionAstilectron: VersionAstilectron,
 			VersionElectron:    VersionElectron,
 		},
-		Debug:         *debug,
+		Debug:         *debugFlag,
 		Logger:        log,
 		MenuOptions:   menuOptions,
 		RestoreAssets: RestoreAssets,

pkg/electron/kube/config.go

@@ -0,0 +1,120 @@
+package kube
+
+import (
+	"os"
+	"path/filepath"
+	"runtime"
+	"strings"
+
+	"k8s.io/client-go/tools/clientcmd"
+)
+
+// homeDir returns the users home directory, where the '.kube' directory is located.
+// The '.kube' directory contains the configuration file for a Kubernetes cluster.
+func homeDir() string {
+	if h := os.Getenv("HOME"); h != "" {
+		return h
+	}
+
+	// Get the home directory on windows.
+	return os.Getenv("USERPROFILE")
+}
+
+// loadConfigFile loads a single Kubeconfig file. If the "-kubeconfig" flag is set the provided file will be used. If
+// the value is empty the "KUBECONFIG" environment variable or the "~/.kube/config" file is used.
+func loadConfigFile(kubeconfig string) (clientcmd.ClientConfig, error) {
+	if kubeconfig == "" {
+		if os.Getenv("KUBECONFIG") == "" {
+			if home := homeDir(); home != "" {
+				kubeconfig = filepath.Join(home, ".kube", "config")
+			} else {
+				return nil, ErrConfigNotFound
+			}
+		} else {
+			kubeconfig = os.Getenv("KUBECONFIG")
+		}
+	}
+
+	return clientcmd.NewNonInteractiveDeferredLoadingClientConfig(
+		&clientcmd.ClientConfigLoadingRules{ExplicitPath: kubeconfig},
+		&clientcmd.ConfigOverrides{},
+	), nil
+}
+
+// loadConfigFiles loads and merged multiple Kubeconfig file by the provided glob. If a file matches the exlude glob the
+// file isn't included in the final config object.
+func loadConfigFiles(includeKubeconfig, excludeKubeconfig string) (clientcmd.ClientConfig, error) {
+	includes := getFilesFromString(includeKubeconfig)
+	excludes := getFilesFromString(excludeKubeconfig)
+
+	includeFiles, err := getFilesForGlobs(includes)
+	if err != nil {
+		return nil, err
+	}
+
+	excludeFiles, err := getFilesForGlobs(excludes)
+	if err != nil {
+		return nil, err
+	}
+
+	var kubeconfigFiles []string
+	for _, file := range includeFiles {
+		if !fileExistsInFiles(file, excludeFiles) {
+			kubeconfigFiles = append(kubeconfigFiles, file)
+		}
+	}
+
+	return clientcmd.NewNonInteractiveDeferredLoadingClientConfig(
+		&clientcmd.ClientConfigLoadingRules{Precedence: kubeconfigFiles},
+		&clientcmd.ConfigOverrides{},
+	), nil
+}
+
+// getFilesFromString returns a slice of files from a single string. The string is splitted by the "," character. If an
+// item starts with "~/" the tilde character is replaced with the path of the home directory.
+//
+// Note: On macOS the home directory must be lowercase.
+func getFilesFromString(filesStr string) []string {
+	home := homeDir()
+	if runtime.GOOS == "darwin" {
+		home = strings.ToLower(home)
+	}
+
+	var files []string
+	for _, file := range strings.Split(filesStr, ",") {
+		if strings.HasPrefix(file, "~/") {
+			files = append(files, home+strings.TrimPrefix(file, "~"))
+		} else {
+			files = append(files, file)
+		}
+	}
+
+	return files
+}
+
+// getFilesForGlobs returns a list of files for a list of globs using the filepath.Glob function. The accepted pattern
+// for a glob can be found here: https://golang.org/pkg/path/filepath/#Match
+func getFilesForGlobs(globs []string) ([]string, error) {
+	var files []string
+	for _, glob := range globs {
+		f, err := filepath.Glob(glob)
+		if err != nil {
+			return nil, err
+		}
+		files = append(files, f...)
+	}
+
+	return files, nil
+}
+
+// fileExistsInFiles returns true when a file exists in a slice of files. When the file doesn't exists in the slice the
+// function returns false.
+func fileExistsInFiles(file string, files []string) bool {
+	for _, f := range files {
+		if f == file {
+			return true
+		}
+	}
+
+	return false
+}

pkg/electron/kube/kube.go

@@ -2,8 +2,6 @@ package kube
 
 import (
 	"errors"
-	"os"
-	"path/filepath"
 	"time"
 
 	"k8s.io/client-go/kubernetes"
@@ -37,38 +35,23 @@ type Cluster struct {
 	Namespace                string `json:"namespace"`
 }
 
-// homeDir returns the users home directory, where the '.kube' directory is located.
-// The '.kube' directory contains the configuration file for a Kubernetes cluster.
-func homeDir() string {
-	if h := os.Getenv("HOME"); h != "" {
-		return h
-	}
-
-	// Get the home directory on windows.
-	return os.Getenv("USERPROFILE")
-}
-
 // NewClient returns a new API client for a Kubernetes cluster.
-// If the cluster parameter is true the client is configured inside the cluster. If the cluster parameter is false the
-// client is configures outside the cluster.
-func NewClient(kubeconfig string) (*Client, error) {
-	if kubeconfig == "" {
-		if os.Getenv("KUBECONFIG") == "" {
-			if home := homeDir(); home != "" {
-				kubeconfig = filepath.Join(home, ".kube", "config")
-			} else {
-				return nil, ErrConfigNotFound
-			}
-		} else {
-			kubeconfig = os.Getenv("KUBECONFIG")
+func NewClient(kubeconfig, kubeconfigInclude, kubeconfigExclude string) (*Client, error) {
+	var config clientcmd.ClientConfig
+	var err error
+
+	if kubeconfigInclude != "" {
+		config, err = loadConfigFiles(kubeconfigInclude, kubeconfigExclude)
+		if err != nil {
+			return nil, err
+		}
+	} else {
+		config, err = loadConfigFile(kubeconfig)
+		if err != nil {
+			return nil, err
 		}
 	}
 
-	config := clientcmd.NewNonInteractiveDeferredLoadingClientConfig(
-		&clientcmd.ClientConfigLoadingRules{ExplicitPath: kubeconfig},
-		&clientcmd.ConfigOverrides{},
-	)
-
 	return &Client{
 		config:     config,
 		kubeconfig: kubeconfig,