Watch for added/removed local extensions (#1482)

Signed-off-by: Panu Horsmalahti <phorsmalahti@mirantis.com>

package.json

@@ -216,7 +216,9 @@
     "@types/react-beautiful-dnd": "^13.0.0",
     "@types/tar": "^4.0.3",
     "array-move": "^3.0.0",
+    "await-lock": "^2.1.0",
     "chalk": "^4.1.0",
+    "chokidar": "^3.4.3",
     "command-exists": "1.2.9",
     "conf": "^7.0.1",
     "crypto-js": "^4.0.0",

src/extensions/extension-discovery.ts

@@ -0,0 +1,329 @@
+import chokidar from "chokidar";
+import { EventEmitter } from "events";
+import fs from "fs-extra";
+import os from "os";
+import path from "path";
+import { getBundledExtensions } from "../common/utils/app-version";
+import logger from "../main/logger";
+import { extensionInstaller, PackageJson } from "./extension-installer";
+import type { LensExtensionId, LensExtensionManifest } from "./lens-extension";
+
+export interface InstalledExtension {
+    readonly manifest: LensExtensionManifest;
+    readonly manifestPath: string;
+    readonly isBundled: boolean; // defined in project root's package.json
+    isEnabled: boolean;
+  }
+
+const logModule = "[EXTENSION-DISCOVERY]";
+const manifestFilename = "package.json";
+
+/**
+ * Returns true if the lstat is for a directory-like file (e.g. isDirectory or symbolic link)
+ * @param lstat the stats to compare
+ */
+const isDirectoryLike = (lstat: fs.Stats) => lstat.isDirectory() || lstat.isSymbolicLink();
+
+/**
+ * Discovers installed bundled and local extensions from the filesystem.
+ * Also watches for added and removed local extensions by watching the directory.
+ * Uses ExtensionInstaller to install dependencies for all of the extensions.
+ * This is also done when a new extension is copied to the local extensions directory.
+ * .init() must be called to start the directory watching.
+ * The class emits events for added and removed extensions:
+ * - "add": When extension is added. The event is of type InstalledExtension
+ * - "remove": When extension is removed. The event is of type LensExtensionId
+ */
+export class ExtensionDiscovery {
+  protected bundledFolderPath: string;
+
+  private loadStarted = false;
+
+  // This promise is resolved when .load() is finished.
+  // This allows operations to be added after .load() success.
+  private loaded: Promise<void>;
+
+  // These are called to either resolve or reject this.loaded promise
+  private resolveLoaded: () => void;
+  private rejectLoaded: (error: any) => void;
+
+  public events: EventEmitter;
+
+  constructor() {
+    this.loaded = new Promise((resolve, reject) => {
+      this.resolveLoaded = resolve;
+      this.rejectLoaded = reject;
+    });
+
+    this.events = new EventEmitter();
+  }
+
+  // Each extension is added as a single dependency to this object, which is written as package.json.
+  // Each dependency key is the name of the dependency, and
+  // each dependency value is the non-symlinked path to the dependency (folder).
+  protected packagesJson: PackageJson = {
+    dependencies: {}
+  };
+
+  get localFolderPath(): string {
+    return path.join(os.homedir(), ".k8slens", "extensions");
+  }
+
+  get packageJsonPath() {
+    return path.join(extensionInstaller.extensionPackagesRoot, manifestFilename);
+  }
+
+  get inTreeTargetPath() {
+    return path.join(extensionInstaller.extensionPackagesRoot, "extensions");
+  }
+
+  get inTreeFolderPath(): string {
+    return path.resolve(__static, "../extensions");
+  }
+
+  get nodeModulesPath(): string {
+    return path.join(extensionInstaller.extensionPackagesRoot, "node_modules");
+  }
+
+  /**
+   * Initializes the class and setups the file watcher for added/removed local extensions.
+   */
+  init() {
+    this.watchExtensions();
+  }
+    
+  /**
+   * Watches for added/removed local extensions.
+   * Dependencies are installed automatically after an extension folder is copied.
+   */
+  async watchExtensions() {
+    logger.info(`${logModule} watching extension add/remove in ${this.localFolderPath}`);
+
+    // Wait until .load() has been called and has been resolved
+    await this.loaded;
+
+    // chokidar works better than fs.watch
+    chokidar.watch(this.localFolderPath, {
+      // Dont watch recursively into subdirectories
+      depth: 0,
+      // Try to wait until the file has been completely copied.
+      // The OS might emit an event for added file even it's not completely written to the filesysten.
+      awaitWriteFinish: {
+        // Wait 300ms until the file size doesn't change to consider the file written.
+        // For a small file like package.json this should be plenty of time.
+        stabilityThreshold: 300
+      }
+    })
+      // Extension add is detected by watching "<extensionDir>package.json" add
+      .on("add", this.handleWatchFileAdd)
+      // Extension remove is detected by watching <extensionDir>" unlink
+      .on("unlinkDir", this.handleWatchUnlinkDir);
+  }
+
+  handleWatchFileAdd =  async (filePath: string) => {
+    if (path.basename(filePath) === manifestFilename) {
+      try {
+        const absPath = path.dirname(filePath);
+
+        // this.loadExtensionFromPath updates this.packagesJson
+        const extension = await this.loadExtensionFromPath(absPath);
+
+        if (extension) {
+          // Install dependencies for the new extension
+          await this.installPackages();
+
+          logger.info(`${logModule} Added extension ${extension.manifest.name}`);
+          this.events.emit("add", extension);
+        }
+      } catch (error) {
+        console.error(error);
+      }
+    }
+  };
+
+  handleWatchUnlinkDir = async (filePath: string) => {
+    // filePath is the non-symlinked path to the extension folder
+    // this.packagesJson.dependencies value is the non-symlinked path to the extension folder
+    // LensExtensionId in extension-loader is the symlinked path to the extension folder manifest file
+
+    // Check that the removed path is directly under this.localFolderPath
+    // Note that the watcher can create unlink events for subdirectories of the extension
+    const extensionFolderName = path.basename(filePath);
+
+    if (path.relative(this.localFolderPath, filePath) === extensionFolderName) {
+      const extensionName: string | undefined = Object
+        .entries(this.packagesJson.dependencies)
+        .find(([_name, extensionFolder]) => filePath === extensionFolder)?.[0];
+
+      if (extensionName !== undefined) {
+        delete this.packagesJson.dependencies[extensionName];
+
+        // Reinstall dependencies to remove the extension from package.json
+        await this.installPackages();
+
+        // The path to the manifest file is the lens extension id
+        // Note that we need to use the symlinked path
+        const lensExtensionId = path.join(this.nodeModulesPath, extensionName, "package.json");
+
+        logger.info(`${logModule} removed extension ${extensionName}`);
+        this.events.emit("remove", lensExtensionId as LensExtensionId);
+      } else {
+        logger.warn(`${logModule} extension ${extensionFolderName} not found, can't remove`);
+      }
+    }
+  };
+
+  async load(): Promise<Map<LensExtensionId, InstalledExtension>> {
+    if (this.loadStarted) {
+      // The class is simplified by only supporting .load() to be called once
+      throw new Error("ExtensionDiscovery.load() can be only be called once");
+    }
+
+    this.loadStarted = true;
+
+    try {
+      logger.info(`${logModule} loading extensions from ${extensionInstaller.extensionPackagesRoot}`);
+
+      if (fs.existsSync(path.join(extensionInstaller.extensionPackagesRoot, "package-lock.json"))) {
+        await fs.remove(path.join(extensionInstaller.extensionPackagesRoot, "package-lock.json"));
+      }
+
+      try {
+        await fs.access(this.inTreeFolderPath, fs.constants.W_OK);
+        this.bundledFolderPath = this.inTreeFolderPath;
+      } catch {
+      // we need to copy in-tree extensions so that we can symlink them properly on "npm install"
+        await fs.remove(this.inTreeTargetPath);
+        await fs.ensureDir(this.inTreeTargetPath);
+        await fs.copy(this.inTreeFolderPath, this.inTreeTargetPath);
+        this.bundledFolderPath = this.inTreeTargetPath;
+      }
+
+      await fs.ensureDir(this.nodeModulesPath);
+      await fs.ensureDir(this.localFolderPath);
+
+      const extensions = await this.loadExtensions();
+
+      // resolve the loaded promise
+      this.resolveLoaded();
+
+      return extensions;
+    } catch (error) {
+      this.rejectLoaded(error);
+    }
+  }
+
+  protected async getByManifest(manifestPath: string, { isBundled = false, isEnabled = isBundled }: {
+    isBundled?: boolean;
+    isEnabled?: boolean;
+  } = {}): Promise<InstalledExtension | null> {
+    let manifestJson: LensExtensionManifest;
+
+    try {
+      // check manifest file for existence
+      fs.accessSync(manifestPath, fs.constants.F_OK);
+
+      manifestJson = __non_webpack_require__(manifestPath);
+      this.packagesJson.dependencies[manifestJson.name] = path.dirname(manifestPath);
+
+      return {
+        manifestPath: path.join(this.nodeModulesPath, manifestJson.name, "package.json"),
+        manifest: manifestJson,
+        isBundled,
+        isEnabled,
+      };
+    } catch (error) {
+      logger.error(`${logModule}: can't install extension at ${manifestPath}: ${error}`, { manifestJson });
+
+      return null;
+    }
+  }
+
+  async loadExtensions(): Promise<Map<LensExtensionId, InstalledExtension>> {
+    const bundledExtensions = await this.loadBundledExtensions();
+    const localExtensions = await this.loadFromFolder(this.localFolderPath);
+    await this.installPackages();
+    const extensions = bundledExtensions.concat(localExtensions);
+
+    return new Map(extensions.map(ext => [ext.manifestPath, ext]));
+  }
+
+  /**
+   * Write package.json to file system and install dependencies.
+   */
+  installPackages() {
+    return extensionInstaller.installPackages(this.packageJsonPath, this.packagesJson);
+  }
+
+  async loadBundledExtensions() {
+    const extensions: InstalledExtension[] = [];
+    const folderPath = this.bundledFolderPath;
+    const bundledExtensions = getBundledExtensions();
+    const paths = await fs.readdir(folderPath);
+
+    for (const fileName of paths) {
+      if (!bundledExtensions.includes(fileName)) {
+        continue;
+      }
+
+      const absPath = path.resolve(folderPath, fileName);
+      const extension = await this.loadExtensionFromPath(absPath, { isBundled: true });
+
+      if (extension) {
+        extensions.push(extension);
+      }
+    }
+    logger.debug(`${logModule}: ${extensions.length} extensions loaded`, { folderPath, extensions });
+
+    return extensions;
+  }
+
+  async loadFromFolder(folderPath: string): Promise<InstalledExtension[]> {
+    const bundledExtensions = getBundledExtensions();
+    const extensions: InstalledExtension[] = [];
+    const paths = await fs.readdir(folderPath);
+
+    for (const fileName of paths) {
+      // do not allow to override bundled extensions
+      if (bundledExtensions.includes(fileName)) {
+        continue;
+      }
+
+      const absPath = path.resolve(folderPath, fileName);
+
+      if (!fs.existsSync(absPath)) {
+        continue;
+      }
+
+      const lstat = await fs.lstat(absPath);
+
+      // skip non-directories
+      if (!isDirectoryLike(lstat)) {
+        continue;
+      }
+
+      const extension = await this.loadExtensionFromPath(absPath);
+
+      if (extension) {
+        extensions.push(extension);
+      }
+    }
+
+    logger.debug(`${logModule}: ${extensions.length} extensions loaded`, { folderPath, extensions });
+    return extensions;
+  }
+
+  /**
+   * Loads extension from absolute path, updates this.packagesJson to include it and returns the extension.
+   */
+  async loadExtensionFromPath(absPath: string, { isBundled = false, isEnabled = isBundled }: {
+    isBundled?: boolean;
+    isEnabled?: boolean;
+  } = {}): Promise<InstalledExtension | null> {
+    const manifestPath = path.resolve(absPath, manifestFilename);
+
+    return this.getByManifest(manifestPath, { isBundled, isEnabled });
+  }
+}
+
+export const extensionDiscovery = new ExtensionDiscovery();

src/extensions/extension-installer.ts

@@ -0,0 +1,69 @@
+import AwaitLock from 'await-lock';
+import child_process from "child_process";
+import fs from "fs-extra";
+import path from "path";
+import logger from "../main/logger";
+import { extensionPackagesRoot } from "./extension-loader";
+
+const logModule = "[EXTENSION-INSTALLER]";
+
+type Dependencies = {
+  [name: string]: string;
+};
+
+// Type for the package.json file that is written by ExtensionInstaller
+export type PackageJson = {
+  dependencies: Dependencies;
+};
+
+/**
+ * Installs dependencies for extensions
+ */
+export class ExtensionInstaller {
+  private installLock = new AwaitLock();
+
+  get extensionPackagesRoot() {
+    return extensionPackagesRoot();
+  }
+
+  get npmPath() {
+    return __non_webpack_require__.resolve('npm/bin/npm-cli');
+  }
+
+  installDependencies(): Promise<void> {
+    return new Promise((resolve, reject) => {
+      logger.info(`${logModule} installing dependencies at ${extensionPackagesRoot()}`);
+      const child = child_process.fork(this.npmPath, ["install", "--silent", "--no-audit", "--only=prod", "--prefer-offline", "--no-package-lock"], {
+        cwd: extensionPackagesRoot(),
+        silent: true
+      });
+      child.on("close", () => {
+        resolve();
+      });
+      child.on("error", (err) => {
+        reject(err);
+      });
+    });
+  }
+
+  /**
+   * Write package.json to the file system and execute npm install for it.
+   */
+  async installPackages(packageJsonPath: string, packagesJson: PackageJson): Promise<void> {
+    // Mutual exclusion to install packages in sequence
+    await this.installLock.acquireAsync();
+
+    try {
+    // Write the package.json which will be installed in .installDependencies()
+      await fs.writeFile(path.join(packageJsonPath), JSON.stringify(packagesJson, null, 2), {
+        mode: 0o600
+      });
+
+      await this.installDependencies();
+    } finally {
+      this.installLock.release();
+    }
+  }
+}
+
+export const extensionInstaller = new ExtensionInstaller();

src/extensions/extension-loader.ts

@@ -1,20 +1,25 @@
+import { app, ipcRenderer, remote } from "electron";
+import { action, computed, observable, reaction, toJS, when } from "mobx";
+import path from "path";
+import { broadcastMessage, handleRequest, requestMain, subscribeToBroadcast } from "../common/ipc";
+import logger from "../main/logger";
+import type { InstalledExtension } from "./extension-discovery";
+import { extensionsStore } from "./extensions-store";
 import type { LensExtension, LensExtensionConstructor, LensExtensionId } from "./lens-extension";
 import type { LensMainExtension } from "./lens-main-extension";
 import type { LensRendererExtension } from "./lens-renderer-extension";
-import type { InstalledExtension } from "./extension-manager";
-import path from "path";
-import { broadcastMessage, handleRequest, requestMain, subscribeToBroadcast } from "../common/ipc";
-import { action, computed, observable, reaction, toJS, when } from "mobx";
-import logger from "../main/logger";
-import { app, ipcRenderer, remote } from "electron";
 import * as registries from "./registries";
-import { extensionsStore } from "./extensions-store";
 
 // lazy load so that we get correct userData
 export function extensionPackagesRoot() {
   return path.join((app || remote.app).getPath("userData"));
 }
 
+const logModule = "[EXTENSIONS-LOADER]";
+
+/**
+ * Loads installed extensions to the Lens application
+ */
 export class ExtensionLoader {
   protected extensions = observable.map<LensExtensionId, InstalledExtension>();
   protected instances = observable.map<LensExtensionId, LensExtension>();
@@ -47,6 +52,17 @@ export class ExtensionLoader {
     this.extensions.replace(extensions);
   }
 
+  addExtension(extension: InstalledExtension) {
+    this.extensions.set(extension.manifestPath as LensExtensionId, extension);
+  }
+
+  removeExtension(lensExtensionId: LensExtensionId) {
+    // TODO: Remove the extension properly (from menus etc.)
+    if (!this.extensions.delete(lensExtensionId)) {
+      throw new Error(`Can't remove extension ${lensExtensionId}, doesn't exist.`);
+    }
+  }
+
   protected async initMain() {
     this.isLoaded = true;
     this.loadOnMain();
@@ -77,14 +93,14 @@ export class ExtensionLoader {
   }
 
   loadOnMain() {
-    logger.info('[EXTENSIONS-LOADER]: load on main');
+    logger.info(`${logModule}: load on main`);
     this.autoInitExtensions((ext: LensMainExtension) => [
       registries.menuRegistry.add(ext.appMenus)
     ]);
   }
 
   loadOnClusterManagerRenderer() {
-    logger.info('[EXTENSIONS-LOADER]: load on main renderer (cluster manager)');
+    logger.info(`${logModule}: load on main renderer (cluster manager)`);
     this.autoInitExtensions((ext: LensRendererExtension) => [
       registries.globalPageRegistry.add(ext.globalPages, ext),
       registries.globalPageMenuRegistry.add(ext.globalPageMenus, ext),
@@ -95,7 +111,7 @@ export class ExtensionLoader {
   }
 
   loadOnClusterRenderer() {
-    logger.info('[EXTENSIONS-LOADER]: load on cluster renderer (dashboard)');
+    logger.info(`${logModule}: load on cluster renderer (dashboard)`);
     this.autoInitExtensions((ext: LensRendererExtension) => [
       registries.clusterPageRegistry.add(ext.clusterPages, ext),
       registries.clusterPageMenuRegistry.add(ext.clusterPageMenus, ext),
@@ -118,14 +134,15 @@ export class ExtensionLoader {
             instance.enable();
             this.instances.set(extId, instance);
           } catch (err) {
-            logger.error(`[EXTENSION-LOADER]: activation extension error`, { ext, err });
+            logger.error(`${logModule}: activation extension error`, { ext, err });
           }
         } else if (!ext.isEnabled && instance) {
+          logger.info(`${logModule} deleting extension ${extId}`);
           try {
             instance.disable();
             this.instances.delete(extId);
           } catch (err) {
-            logger.error(`[EXTENSION-LOADER]: deactivation extension error`, { ext, err });
+            logger.error(`${logModule}: deactivation extension error`, { ext, err });
           }
         }
       }
@@ -146,7 +163,7 @@ export class ExtensionLoader {
         return __non_webpack_require__(extEntrypoint).default;
       }
     } catch (err) {
-      console.error(`[EXTENSION-LOADER]: can't load extension main at ${extEntrypoint}: ${err}`, { extension });
+      console.error(`${logModule}: can't load extension main at ${extEntrypoint}: ${err}`, { extension });
       console.trace(err);
     }
   }

src/extensions/extension-manager.ts

@@ -1,172 +0,0 @@
-import type { LensExtensionId, LensExtensionManifest } from "./lens-extension";
-import path from "path";
-import os from "os";
-import fs from "fs-extra";
-import child_process from "child_process";
-import logger from "../main/logger";
-import { extensionPackagesRoot } from "./extension-loader";
-import { getBundledExtensions } from "../common/utils/app-version";
-
-export interface InstalledExtension {
-  readonly manifest: LensExtensionManifest;
-  readonly manifestPath: string;
-  readonly isBundled: boolean; // defined in project root's package.json
-  isEnabled: boolean;
-}
-
-type Dependencies = {
-  [name: string]: string;
-};
-
-type PackageJson = {
-  dependencies: Dependencies;
-};
-
-export class ExtensionManager {
-
-  protected bundledFolderPath: string;
-
-  protected packagesJson: PackageJson = {
-    dependencies: {}
-  };
-
-  get extensionPackagesRoot() {
-    return extensionPackagesRoot();
-  }
-
-  get inTreeTargetPath() {
-    return path.join(this.extensionPackagesRoot, "extensions");
-  }
-
-  get inTreeFolderPath(): string {
-    return path.resolve(__static, "../extensions");
-  }
-
-  get nodeModulesPath(): string {
-    return path.join(this.extensionPackagesRoot, "node_modules");
-  }
-
-  get localFolderPath(): string {
-    return path.join(os.homedir(), ".k8slens", "extensions");
-  }
-
-  get npmPath() {
-    return __non_webpack_require__.resolve('npm/bin/npm-cli');
-  }
-
-  get packageJsonPath() {
-    return path.join(this.extensionPackagesRoot, "package.json");
-  }
-
-  async load(): Promise<Map<LensExtensionId, InstalledExtension>> {
-    logger.info("[EXTENSION-MANAGER] loading extensions from " + this.extensionPackagesRoot);
-    if (fs.existsSync(path.join(this.extensionPackagesRoot, "package-lock.json"))) {
-      await fs.remove(path.join(this.extensionPackagesRoot, "package-lock.json"));
-    }
-    try {
-      await fs.access(this.inTreeFolderPath, fs.constants.W_OK);
-      this.bundledFolderPath = this.inTreeFolderPath;
-    } catch {
-      // we need to copy in-tree extensions so that we can symlink them properly on "npm install"
-      await fs.remove(this.inTreeTargetPath);
-      await fs.ensureDir(this.inTreeTargetPath);
-      await fs.copy(this.inTreeFolderPath, this.inTreeTargetPath);
-      this.bundledFolderPath = this.inTreeTargetPath;
-    }
-    await fs.ensureDir(this.nodeModulesPath);
-    await fs.ensureDir(this.localFolderPath);
-    return await this.loadExtensions();
-  }
-
-  protected async getByManifest(manifestPath: string, { isBundled = false } = {}): Promise<InstalledExtension> {
-    let manifestJson: LensExtensionManifest;
-    try {
-      fs.accessSync(manifestPath, fs.constants.F_OK); // check manifest file for existence
-      manifestJson = __non_webpack_require__(manifestPath);
-      this.packagesJson.dependencies[manifestJson.name] = path.dirname(manifestPath);
-
-      logger.info("[EXTENSION-MANAGER] installed extension " + manifestJson.name);
-      return {
-        manifestPath: path.join(this.nodeModulesPath, manifestJson.name, "package.json"),
-        manifest: manifestJson,
-        isBundled: isBundled,
-        isEnabled: isBundled,
-      };
-    } catch (err) {
-      logger.error(`[EXTENSION-MANAGER]: can't install extension at ${manifestPath}: ${err}`, { manifestJson });
-    }
-  }
-
-  protected installPackages(): Promise<void> {
-    return new Promise((resolve, reject) => {
-      const child = child_process.fork(this.npmPath, ["install", "--silent", "--no-audit", "--only=prod", "--prefer-offline", "--no-package-lock"], {
-        cwd: extensionPackagesRoot(),
-        silent: true
-      });
-      child.on("close", () => {
-        resolve();
-      });
-      child.on("error", (err) => {
-        reject(err);
-      });
-    });
-  }
-
-  async loadExtensions() {
-    const bundledExtensions = await this.loadBundledExtensions();
-    const localExtensions = await this.loadFromFolder(this.localFolderPath);
-    await fs.writeFile(path.join(this.packageJsonPath), JSON.stringify(this.packagesJson, null, 2), { mode: 0o600 });
-    await this.installPackages();
-    const extensions = bundledExtensions.concat(localExtensions);
-    return new Map(extensions.map(ext => [ext.manifestPath, ext]));
-  }
-
-  async loadBundledExtensions() {
-    const extensions: InstalledExtension[] = [];
-    const folderPath = this.bundledFolderPath;
-    const bundledExtensions = getBundledExtensions();
-    const paths = await fs.readdir(folderPath);
-    for (const fileName of paths) {
-      if (!bundledExtensions.includes(fileName)) {
-        continue;
-      }
-      const absPath = path.resolve(folderPath, fileName);
-      const manifestPath = path.resolve(absPath, "package.json");
-      const ext = await this.getByManifest(manifestPath, { isBundled: true }).catch(() => null);
-      if (ext) {
-        extensions.push(ext);
-      }
-    }
-    logger.debug(`[EXTENSION-MANAGER]: ${extensions.length} extensions loaded`, { folderPath, extensions });
-    return extensions;
-  }
-
-  async loadFromFolder(folderPath: string): Promise<InstalledExtension[]> {
-    const bundledExtensions = getBundledExtensions();
-    const extensions: InstalledExtension[] = [];
-    const paths = await fs.readdir(folderPath);
-    for (const fileName of paths) {
-      if (bundledExtensions.includes(fileName)) { // do no allow to override bundled extensions
-        continue;
-      }
-      const absPath = path.resolve(folderPath, fileName);
-      if (!fs.existsSync(absPath)) {
-        continue;
-      }
-      const lstat = await fs.lstat(absPath);
-      if (!lstat.isDirectory() && !lstat.isSymbolicLink()) { // skip non-directories
-        continue;
-      }
-      const manifestPath = path.resolve(absPath, "package.json");
-      const ext = await this.getByManifest(manifestPath).catch(() => null);
-      if (ext) {
-        extensions.push(ext);
-      }
-    }
-
-    logger.debug(`[EXTENSION-MANAGER]: ${extensions.length} extensions loaded`, { folderPath, extensions });
-    return extensions;
-  }
-}
-
-export const extensionManager = new ExtensionManager();

src/extensions/lens-extension.ts

@@ -1,4 +1,4 @@
-import type { InstalledExtension } from "./extension-manager";
+import type { InstalledExtension } from "./extension-discovery";
 import { action, observable, reaction } from "mobx";
 import logger from "../main/logger";
 
@@ -27,6 +27,7 @@ export class LensExtension {
   }
 
   get id(): LensExtensionId {
+    // This is the symlinked path under node_modules
     return this.manifestPath;
   }
 

src/main/index.ts

@@ -21,8 +21,9 @@ import { userStore } from "../common/user-store";
 import { workspaceStore } from "../common/workspace-store";
 import { appEventBus } from "../common/event-bus";
 import { extensionLoader } from "../extensions/extension-loader";
-import { extensionManager } from "../extensions/extension-manager";
 import { extensionsStore } from "../extensions/extensions-store";
+import { InstalledExtension, extensionDiscovery } from "../extensions/extension-discovery";
+import type { LensExtensionId } from "../extensions/lens-extension";
 
 const workingDir = path.join(app.getPath("appData"), appName);
 let proxyPort: number;
@@ -79,8 +80,22 @@ app.on("ready", async () => {
   }
 
   extensionLoader.init();
+
+  extensionDiscovery.init();
   windowManager = WindowManager.getInstance<WindowManager>(proxyPort);
-  extensionLoader.initExtensions(await extensionManager.load()); // call after windowManager to see splash earlier
+
+  // call after windowManager to see splash earlier
+  const extensions = await extensionDiscovery.load();
+
+  // Subscribe to extensions that are copied or deleted to/from the extensions folder
+  extensionDiscovery.events.on("add", (extension: InstalledExtension) => {
+    extensionLoader.addExtension(extension);
+  });
+  extensionDiscovery.events.on("remove", (lensExtensionId: LensExtensionId) => {
+    extensionLoader.removeExtension(lensExtensionId);
+  });
+
+  extensionLoader.initExtensions(extensions);
 
   setTimeout(() => {
     appEventBus.emit({ name: "service", action: "start" });

src/renderer/components/+extensions/extensions.tsx

@@ -11,7 +11,7 @@ import { Input } from "../input";
 import { Icon } from "../icon";
 import { PageLayout } from "../layout/page-layout";
 import { extensionLoader } from "../../../extensions/extension-loader";
-import { extensionManager } from "../../../extensions/extension-manager";
+import { extensionDiscovery } from "../../../extensions/extension-discovery";
 
 @observer
 export class Extensions extends React.Component {
@@ -29,7 +29,7 @@ export class Extensions extends React.Component {
   }
 
   get extensionsPath() {
-    return extensionManager.localFolderPath;
+    return extensionDiscovery.localFolderPath;
   }
 
   renderInfo() {

yarn.lock

@@ -3262,6 +3262,11 @@ atob@^2.1.2:
   resolved "https://registry.yarnpkg.com/atob/-/atob-2.1.2.tgz#6d9517eb9e030d2436666651e86bd9f6f13533c9"
   integrity sha512-Wm6ukoaOGJi/73p/cl2GvLjTI5JM1k/O14isD73YML8StrH/7/lRFgmg8nICZgD3bZZvjwCGxtMOD3wWNAu8cg==
 
+await-lock@^2.1.0:
+  version "2.1.0"
+  resolved "https://registry.yarnpkg.com/await-lock/-/await-lock-2.1.0.tgz#bc78c51d229a34d5d90965a1c94770e772c6145e"
+  integrity sha512-t7Zm5YGgEEc/3eYAicF32m/TNvL+XOeYZy9CvBUeJY/szM7frLolFylhrlZNWV/ohWhcUXygrBGjYmoQdxF4CQ==
+
 aws-sign2@~0.7.0:
   version "0.7.0"
   resolved "https://registry.yarnpkg.com/aws-sign2/-/aws-sign2-0.7.0.tgz#b46e890934a9591f2d2f6f86d7e6a9f1b3fe76a8"
@@ -4116,7 +4121,7 @@ chokidar@^3.2.2:
   optionalDependencies:
     fsevents "~2.1.2"
 
-chokidar@^3.4.1:
+chokidar@^3.4.1, chokidar@^3.4.3:
   version "3.4.3"
   resolved "https://registry.yarnpkg.com/chokidar/-/chokidar-3.4.3.tgz#c1df38231448e45ca4ac588e6c79573ba6a57d5b"
   integrity sha512-DtM3g7juCXQxFVSNPNByEC2+NImtBuxQQvWlHunpJIS5Ocr0lG306cC7FCi7cEA0fzmybPUIl4txBIobk1gGOQ==