Add option to list plugins

This change creates a CLI option in the backend + desktop to list all
plugins, with a distinction between static/shipped plugins and
user-added ones.

Fixes: #2161

Signed-off-by: Evangelos Skopelitis <eskopelitis@microsoft.com>

app/electron/main.ts

@@ -69,6 +69,10 @@ const args = yargs(hideBin(process.argv))
       describe: 'Disable use of GPU. For people who may have buggy graphics drivers',
       type: 'boolean',
     },
+    'list-plugins': {
+      describe: 'List all static and user-added plugins.',
+      type: 'boolean',
+    },
   })
   .positional('kubeconfig', {
     describe:
@@ -78,6 +82,37 @@ const args = yargs(hideBin(process.argv))
   .help()
   .parseSync();
 
+const listPlugins = args['list-plugins'] === true;
+
+// If the user wants to list plugins, we don't need to start the app.
+if (listPlugins) {
+  const staticDir = path.join(process.resourcesPath, '.plugins');
+  const pluginsDir = path.join(app.getPath('userData'), 'plugins');
+
+  const staticPlugins = fs.existsSync(staticDir) ? fs.readdirSync(staticDir) : [];
+  const userPlugins = fs.existsSync(pluginsDir) ? fs.readdirSync(pluginsDir) : [];
+
+  if (staticPlugins.length > 0) {
+    console.log(`  Static Plugins (${staticDir}):`);
+    staticPlugins.forEach(plugin => {
+      console.log(`  - ${plugin}`);
+    });
+  } else {
+    console.log(`  No static plugins found.`);
+  }
+
+  if (userPlugins.length > 0) {
+    console.log(`  User-added Plugins (${pluginsDir}):`);
+    userPlugins.forEach(plugin => {
+      console.log(`  - ${plugin}`);
+    });
+  } else {
+    console.log(`  No user-added plugins found.`);
+  }
+
+  process.exit(0);
+}
+
 const isHeadlessMode = args.headless === true;
 let disableGPU = args['disable-gpu'] === true;
 const defaultPort = 4466;

backend/cmd/server.go

@@ -8,6 +8,7 @@ import (
 	"github.com/headlamp-k8s/headlamp/backend/pkg/config"
 	"github.com/headlamp-k8s/headlamp/backend/pkg/kubeconfig"
 	"github.com/headlamp-k8s/headlamp/backend/pkg/logger"
+	"github.com/headlamp-k8s/headlamp/backend/pkg/plugins"
 )
 
 func main() {
@@ -17,6 +18,15 @@ func main() {
 		os.Exit(1)
 	}
 
+	if conf.ListPlugins {
+		if err := plugins.ListPlugins(conf.StaticDir, conf.PluginsDir); err != nil {
+			logger.Log(logger.LevelError, nil, err, "listing plugins")
+			os.Exit(1)
+		}
+
+		os.Exit(0)
+	}
+
 	cache := cache.New[interface{}]()
 	kubeConfigStore := kubeconfig.NewContextStore()
 

backend/pkg/config/config.go

@@ -25,6 +25,7 @@ type Config struct {
 	InsecureSsl           bool   `koanf:"insecure-ssl"`
 	EnableHelm            bool   `koanf:"enable-helm"`
 	EnableDynamicClusters bool   `koanf:"enable-dynamic-clusters"`
+	ListPlugins           bool   `koanf:"list-plugins"`
 	Port                  uint   `koanf:"port"`
 	KubeConfigPath        string `koanf:"kubeconfig"`
 	StaticDir             string `koanf:"html-static-dir"`
@@ -153,6 +154,7 @@ func flagset() *flag.FlagSet {
 	f.Bool("dev", false, "Allow connections from other origins")
 	f.Bool("insecure-ssl", false, "Accept/Ignore all server SSL certificates")
 	f.Bool("enable-dynamic-clusters", false, "Enable dynamic clusters, which stores stateless clusters in the frontend.")
+	f.Bool("list-plugins", false, "List all static and user-added plugins")
 
 	f.String("kubeconfig", "", "Absolute path to the kubeconfig file")
 	f.String("html-static-dir", "", "Static HTML directory to serve")

backend/pkg/plugins/plugins.go

@@ -77,20 +77,30 @@ func periodicallyWatchSubfolders(watcher *fsnotify.Watcher, path string, interva
 	}
 }
 
-// GeneratePluginPaths takes the staticPluginDir and pluginDir and returns a list of plugin paths.
-func GeneratePluginPaths(staticPluginDir string, pluginDir string) ([]string, error) {
+// generateSeparatePluginPaths takes the staticPluginDir and pluginDir and returns separate lists of plugin paths.
+func generateSeparatePluginPaths(staticPluginDir, pluginDir string) ([]string, []string, error) {
 	var pluginListURLStatic []string
 
 	if staticPluginDir != "" {
 		var err error
 
 		pluginListURLStatic, err = pluginBasePathListForDir(staticPluginDir, "static-plugins")
 		if err != nil {
-			return nil, err
+			return nil, nil, err
 		}
 	}
 
 	pluginListURL, err := pluginBasePathListForDir(pluginDir, "plugins")
+	if err != nil {
+		return nil, nil, err
+	}
+
+	return pluginListURLStatic, pluginListURL, nil
+}
+
+// GeneratePluginPaths generates a concatenated list of plugin paths from the staticPluginDir and pluginDir.
+func GeneratePluginPaths(staticPluginDir, pluginDir string) ([]string, error) {
+	pluginListURLStatic, pluginListURL, err := generateSeparatePluginPaths(staticPluginDir, pluginDir)
 	if err != nil {
 		return nil, err
 	}
@@ -103,6 +113,37 @@ func GeneratePluginPaths(staticPluginDir string, pluginDir string) ([]string, er
 	return pluginListURL, nil
 }
 
+var GenerateSeparatePluginPathsFunc = generateSeparatePluginPaths
+
+// ListPlugins lists the plugins in the static and user-added plugin directories.
+func ListPlugins(staticPluginDir, pluginDir string) error {
+	staticPlugins, userPlugins, err := GenerateSeparatePluginPathsFunc(staticPluginDir, pluginDir)
+	if err != nil {
+		logger.Log(logger.LevelError, nil, err, "listing plugins")
+		return fmt.Errorf("listing plugins: %w", err)
+	}
+
+	if len(staticPlugins) > 0 {
+		fmt.Printf("  Static Plugins (%s):\n", staticPluginDir)
+		for _, plugin := range staticPlugins {
+			fmt.Println("  -", plugin)
+		}
+	} else {
+		fmt.Printf("  No static plugins found.\n")
+	}
+
+	if len(userPlugins) > 0 {
+		fmt.Printf("  User-added Plugins (%s):\n", pluginDir)
+		for _, plugin := range userPlugins {
+			fmt.Println("  -", plugin)
+		}
+	} else {
+		fmt.Printf("  No user-added plugins found.\n")
+	}
+
+	return nil
+}
+
 // pluginBasePathListForDir returns a list of valid plugin paths for the given directory.
 func pluginBasePathListForDir(pluginDir string, baseURL string) ([]string, error) {
 	files, err := os.ReadDir(pluginDir)

backend/pkg/plugins/plugins_test.go

@@ -178,6 +178,22 @@ func TestGeneratePluginPaths(t *testing.T) { //nolint:funlen
 	require.NoError(t, err)
 }
 
+func TestListPlugins(t *testing.T) {
+	originalFunc := plugins.GenerateSeparatePluginPathsFunc
+	defer func() { plugins.GenerateSeparatePluginPathsFunc = originalFunc }()
+
+	// mock the GenerateSeparatePluginPaths function to create lists of plugins
+	plugins.GenerateSeparatePluginPathsFunc = func(staticPluginDir string, pluginDir string) ([]string, []string, error) {
+		staticPlugins := []string{"static-plugin-1", "static-plugin-2"}
+		userPlugins := []string{"user-plugin-1", "user-plugin-2"}
+
+		return staticPlugins, userPlugins, nil
+	}
+
+	err := plugins.ListPlugins("", "")
+	require.NoError(t, err)
+}
+
 func TestHandlePluginEvents(t *testing.T) { //nolint:funlen
 	// Create a temporary directory if it doesn't exist
 	_, err := os.Stat("/tmp/")