Improve documentation of Singleton functions, change to createInstance (#2585)

Signed-off-by: Sebastian Malton <sebastian@malton.name>

src/common/__tests__/cluster-store.test.ts

@@ -59,7 +59,7 @@ describe("empty config", () => {
 
     mockFs(mockOpts);
 
-    await ClusterStore.getInstanceOrCreate().load();
+    await ClusterStore.createInstance().load();
   });
 
   afterEach(() => {
@@ -177,7 +177,7 @@ describe("config with existing clusters", () => {
 
     mockFs(mockOpts);
 
-    return ClusterStore.getInstanceOrCreate().load();
+    return ClusterStore.createInstance().load();
   });
 
   afterEach(() => {
@@ -274,7 +274,7 @@ users:
 
     mockFs(mockOpts);
 
-    return ClusterStore.getInstanceOrCreate().load();
+    return ClusterStore.createInstance().load();
   });
 
   afterEach(() => {
@@ -316,7 +316,7 @@ describe("pre 2.0 config with an existing cluster", () => {
 
     mockFs(mockOpts);
 
-    return ClusterStore.getInstanceOrCreate().load();
+    return ClusterStore.createInstance().load();
   });
 
   afterEach(() => {
@@ -386,7 +386,7 @@ describe("pre 2.6.0 config with a cluster that has arrays in auth config", () =>
 
     mockFs(mockOpts);
 
-    return ClusterStore.getInstanceOrCreate().load();
+    return ClusterStore.createInstance().load();
   });
 
   afterEach(() => {
@@ -430,7 +430,7 @@ describe("pre 2.6.0 config with a cluster icon", () => {
 
     mockFs(mockOpts);
 
-    return ClusterStore.getInstanceOrCreate().load();
+    return ClusterStore.createInstance().load();
   });
 
   afterEach(() => {
@@ -469,7 +469,7 @@ describe("for a pre 2.7.0-beta.0 config without a workspace", () => {
 
     mockFs(mockOpts);
 
-    return ClusterStore.getInstanceOrCreate().load();
+    return ClusterStore.createInstance().load();
   });
 
   afterEach(() => {
@@ -505,7 +505,7 @@ describe("pre 3.6.0-beta.1 config with an existing cluster", () => {
 
     mockFs(mockOpts);
 
-    return ClusterStore.getInstanceOrCreate().load();
+    return ClusterStore.createInstance().load();
   });
 
   afterEach(() => {

src/common/__tests__/hotbar-store.test.ts

@@ -5,7 +5,7 @@ import { HotbarStore } from "../hotbar-store";
 describe("HotbarStore", () => {
   beforeEach(() => {
     ClusterStore.resetInstance();
-    ClusterStore.getInstanceOrCreate();
+    ClusterStore.createInstance();
 
     HotbarStore.resetInstance();
     mockFs({ tmp: { "lens-hotbar-store.json": "{}" } });
@@ -17,7 +17,7 @@ describe("HotbarStore", () => {
 
   describe("load", () => {
     it("loads one hotbar by default", () => {
-      HotbarStore.getInstanceOrCreate().load();
+      HotbarStore.createInstance().load();
       expect(HotbarStore.getInstance().hotbars.length).toEqual(1);
     });
   });

src/common/__tests__/user-store.test.ts

@@ -28,7 +28,7 @@ describe("user store tests", () => {
       UserStore.resetInstance();
       mockFs({ tmp: { "config.json": "{}", "kube_config": "{}" } });
 
-      (UserStore.getInstanceOrCreate() as any).refreshNewContexts = jest.fn(() => Promise.resolve());
+      (UserStore.createInstance() as any).refreshNewContexts = jest.fn(() => Promise.resolve());
 
       return UserStore.getInstance().load();
     });
@@ -102,7 +102,7 @@ describe("user store tests", () => {
         }
       });
 
-      return UserStore.getInstanceOrCreate().load();
+      return UserStore.createInstance().load();
     });
 
     afterEach(() => {

src/common/utils/singleton.ts

@@ -1,10 +1,3 @@
-/**
- * Narrowing class instances to the one.
- * Use "private" or "protected" modifier for constructor (when overriding) to disallow "new" usage.
- *
- * @example
- *  const usersStore: UsersStore = UsersStore.getInstance();
- */
 type StaticThis<T, R extends any[]> = { new(...args: R): T };
 
 export class Singleton {
@@ -13,12 +6,28 @@ export class Singleton {
 
   constructor() {
     if (Singleton.creating.length === 0) {
-      throw new TypeError("A singleton class must be created by getInstanceOrCreate()");
+      throw new TypeError("A singleton class must be created by createInstance()");
     }
   }
 
-  static getInstanceOrCreate<T, R extends any[]>(this: StaticThis<T, R>, ...args: R): T {
+  /**
+   * Creates the single instance of the child class if one was not already created.
+   *
+   * Multiple calls will return the same instance.
+   * Essentially throwing away the arguments to the subsequent calls.
+   *
+   * Note: this is a racy function, if two (or more) calls are racing to call this function
+   * only the first's arguments will be used.
+   * @param this Implicit argument that is the child class type
+   * @param args The constructor arguments for the child class
+   * @returns An instance of the child class
+   */
+  static createInstance<T, R extends any[]>(this: StaticThis<T, R>, ...args: R): T {
     if (!Singleton.instances.has(this)) {
+      if (Singleton.creating.length > 0) {
+        throw new TypeError("Cannot create a second singleton while creating a first");
+      }
+
       Singleton.creating = this.name;
       Singleton.instances.set(this, new this(...args));
       Singleton.creating = "";
@@ -27,6 +36,13 @@ export class Singleton {
     return Singleton.instances.get(this) as T;
   }
 
+  /**
+   * Get the instance of the child class that was previously created.
+   * @param this Implicit argument that is the child class type
+   * @param strict If false will return `undefined` instead of throwing when an instance doesn't exist.
+   * Default: `true`
+   * @returns An instance of the child class
+   */
   static getInstance<T, R extends any[]>(this: StaticThis<T, R>, strict = true): T | undefined {
     if (!Singleton.instances.has(this) && strict) {
       throw new TypeError(`instance of ${this.name} is not created`);
@@ -35,6 +51,13 @@ export class Singleton {
     return Singleton.instances.get(this) as (T | undefined);
   }
 
+  /**
+   * Delete the instance of the child class.
+   *
+   * Note: this doesn't prevent callers of `getInstance` from storing the result in a global.
+   *
+   * There is *no* way in JS or TS to prevent globals like that.
+   */
   static resetInstance() {
     Singleton.instances.delete(this);
   }

src/extensions/__tests__/extension-discovery.test.ts

@@ -21,7 +21,7 @@ describe("ExtensionDiscovery", () => {
   beforeEach(() => {
     ExtensionDiscovery.resetInstance();
     ExtensionsStore.resetInstance();
-    ExtensionsStore.getInstanceOrCreate();
+    ExtensionsStore.createInstance();
   });
 
   it("emits add for added extension", async done => {
@@ -43,7 +43,7 @@ describe("ExtensionDiscovery", () => {
     mockedWatch.mockImplementationOnce(() =>
       (mockWatchInstance) as any
     );
-    const extensionDiscovery = ExtensionDiscovery.getInstanceOrCreate();
+    const extensionDiscovery = ExtensionDiscovery.createInstance();
 
     // Need to force isLoaded to be true so that the file watching is started
     extensionDiscovery.isLoaded = true;
@@ -83,7 +83,7 @@ describe("ExtensionDiscovery", () => {
     mockedWatch.mockImplementationOnce(() =>
       (mockWatchInstance) as any
     );
-    const extensionDiscovery = ExtensionDiscovery.getInstanceOrCreate();
+    const extensionDiscovery = ExtensionDiscovery.createInstance();
 
     // Need to force isLoaded to be true so that the file watching is started
     extensionDiscovery.isLoaded = true;

src/extensions/__tests__/extension-loader.test.ts

@@ -110,7 +110,7 @@ describe("ExtensionLoader", () => {
   });
 
   it.only("renderer updates extension after ipc broadcast", async (done) => {
-    const extensionLoader = ExtensionLoader.getInstanceOrCreate();
+    const extensionLoader = ExtensionLoader.createInstance();
 
     expect(extensionLoader.userExtensions).toMatchInlineSnapshot(`Map {}`);
 
@@ -155,7 +155,7 @@ describe("ExtensionLoader", () => {
     // Disable sending events in this test
     (ipcRenderer.on as any).mockImplementation();
 
-    const extensionLoader = ExtensionLoader.getInstanceOrCreate();
+    const extensionLoader = ExtensionLoader.createInstance();
 
     await extensionLoader.init();
 

src/main/__test__/kube-auth-proxy.test.ts

@@ -50,7 +50,7 @@ describe("kube auth proxy tests", () => {
   beforeEach(() => {
     jest.clearAllMocks();
     UserStore.resetInstance();
-    UserStore.getInstanceOrCreate();
+    UserStore.createInstance();
   });
 
   it("calling exit multiple times shouldn't throw", async () => {

src/main/index.ts

@@ -62,7 +62,7 @@ if (app.commandLine.getSwitchValue("proxy-server") !== "") {
 if (!app.requestSingleInstanceLock()) {
   app.exit();
 } else {
-  const lprm = LensProtocolRouterMain.getInstanceOrCreate();
+  const lprm = LensProtocolRouterMain.createInstance();
 
   for (const arg of process.argv) {
     if (arg.toLowerCase().startsWith("lens://")) {
@@ -73,7 +73,7 @@ if (!app.requestSingleInstanceLock()) {
 }
 
 app.on("second-instance", (event, argv) => {
-  const lprm = LensProtocolRouterMain.getInstanceOrCreate();
+  const lprm = LensProtocolRouterMain.createInstance();
 
   for (const arg of argv) {
     if (arg.toLowerCase().startsWith("lens://")) {
@@ -98,11 +98,11 @@ app.on("ready", async () => {
 
   registerFileProtocol("static", __static);
 
-  const userStore = UserStore.getInstanceOrCreate();
-  const clusterStore = ClusterStore.getInstanceOrCreate();
-  const hotbarStore = HotbarStore.getInstanceOrCreate();
-  const extensionsStore = ExtensionsStore.getInstanceOrCreate();
-  const filesystemStore = FilesystemProvisionerStore.getInstanceOrCreate();
+  const userStore = UserStore.createInstance();
+  const clusterStore = ClusterStore.createInstance();
+  const hotbarStore = HotbarStore.createInstance();
+  const extensionsStore = ExtensionsStore.createInstance();
+  const filesystemStore = FilesystemProvisionerStore.createInstance();
 
   logger.info("💾 Loading stores");
   // preload
@@ -114,36 +114,35 @@ app.on("ready", async () => {
     filesystemStore.load(),
   ]);
 
-  // find free port
-  let proxyPort;
-
   try {
     logger.info("🔑 Getting free port for LensProxy server");
-    proxyPort = await getFreePort();
+    const proxyPort = await getFreePort();
+
+    // create cluster manager
+    ClusterManager.createInstance(proxyPort);
   } catch (error) {
     logger.error(error);
     dialog.showErrorBox("Lens Error", "Could not find a free port for the cluster proxy");
     app.exit();
   }
 
-  // create cluster manager
-  ClusterManager.getInstanceOrCreate(proxyPort);
+  const clusterManager = ClusterManager.getInstance();
 
   // run proxy
   try {
     logger.info("🔌 Starting LensProxy");
     // eslint-disable-next-line unused-imports/no-unused-vars-ts
-    LensProxy.getInstanceOrCreate(proxyPort).listen();
+    LensProxy.createInstance(clusterManager.port).listen();
   } catch (error) {
-    logger.error(`Could not start proxy (127.0.0:${proxyPort}): ${error?.message}`);
-    dialog.showErrorBox("Lens Error", `Could not start proxy (127.0.0:${proxyPort}): ${error?.message || "unknown error"}`);
+    logger.error(`Could not start proxy (127.0.0:${clusterManager.port}): ${error?.message}`);
+    dialog.showErrorBox("Lens Error", `Could not start proxy (127.0.0:${clusterManager.port}): ${error?.message || "unknown error"}`);
     app.exit();
   }
 
   // test proxy connection
   try {
     logger.info("🔎 Testing LensProxy connection ...");
-    const versionFromProxy = await getAppVersionFromProxyServer(proxyPort);
+    const versionFromProxy = await getAppVersionFromProxyServer(clusterManager.port);
 
     if (getAppVersion() !== versionFromProxy) {
       logger.error(`Proxy server responded with invalid response`);
@@ -153,9 +152,9 @@ app.on("ready", async () => {
     logger.error("Checking proxy server connection failed", error);
   }
 
-  const extensionDiscovery = ExtensionDiscovery.getInstanceOrCreate();
+  const extensionDiscovery = ExtensionDiscovery.createInstance();
 
-  ExtensionLoader.getInstanceOrCreate().init();
+  ExtensionLoader.createInstance().init();
   extensionDiscovery.init();
 
   // Start the app without showing the main window when auto starting on login
@@ -163,7 +162,7 @@ app.on("ready", async () => {
   const startHidden = process.argv.includes("--hidden") || (isMac && app.getLoginItemSettings().wasOpenedAsHidden);
 
   logger.info("🖥️  Starting WindowManager");
-  const windowManager = WindowManager.getInstanceOrCreate(proxyPort);
+  const windowManager = WindowManager.createInstance(clusterManager.port);
 
   installDeveloperTools();
 

src/main/protocol-handler/__test__/router.test.ts

@@ -17,10 +17,10 @@ function throwIfDefined(val: any): void {
 
 describe("protocol router tests", () => {
   beforeEach(() => {
-    ExtensionsStore.getInstanceOrCreate();
-    ExtensionLoader.getInstanceOrCreate();
+    ExtensionsStore.createInstance();
+    ExtensionLoader.createInstance();
 
-    const lpr = LensProtocolRouterMain.getInstanceOrCreate();
+    const lpr = LensProtocolRouterMain.createInstance();
 
     lpr.extensionsLoaded = true;
     lpr.rendererLoaded = true;

src/renderer/bootstrap.tsx

@@ -51,16 +51,16 @@ export async function bootstrap(App: AppComponent) {
   await attachChromeDebugger();
   rootElem.classList.toggle("is-mac", isMac);
 
-  ExtensionLoader.getInstanceOrCreate().init();
-  ExtensionDiscovery.getInstanceOrCreate().init();
+  ExtensionLoader.createInstance().init();
+  ExtensionDiscovery.createInstance().init();
 
-  const userStore = UserStore.getInstanceOrCreate();
-  const clusterStore = ClusterStore.getInstanceOrCreate();
-  const extensionsStore = ExtensionsStore.getInstanceOrCreate();
-  const filesystemStore = FilesystemProvisionerStore.getInstanceOrCreate();
-  const themeStore = ThemeStore.getInstanceOrCreate();
-  const hotbarStore = HotbarStore.getInstanceOrCreate();
-  const helmRepoManager = HelmRepoManager.getInstanceOrCreate();
+  const userStore = UserStore.createInstance();
+  const clusterStore = ClusterStore.createInstance();
+  const extensionsStore = ExtensionsStore.createInstance();
+  const filesystemStore = FilesystemProvisionerStore.createInstance();
+  const themeStore = ThemeStore.createInstance();
+  const hotbarStore = HotbarStore.createInstance();
+  const helmRepoManager = HelmRepoManager.createInstance();
 
   // preload common stores
   await Promise.all([

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

@@ -42,16 +42,16 @@ describe("Extensions", () => {
     UserStore.resetInstance();
     ThemeStore.resetInstance();
 
-    await UserStore.getInstanceOrCreate().load();
-    await ThemeStore.getInstanceOrCreate().init();
+    await UserStore.createInstance().load();
+    await ThemeStore.createInstance().init();
 
     ExtensionLoader.resetInstance();
     ExtensionDiscovery.resetInstance();
     Extensions.installStates.clear();
 
-    ExtensionDiscovery.getInstanceOrCreate().uninstallExtension = jest.fn(() => Promise.resolve());
+    ExtensionDiscovery.createInstance().uninstallExtension = jest.fn(() => Promise.resolve());
 
-    ExtensionLoader.getInstanceOrCreate().addExtension({
+    ExtensionLoader.createInstance().addExtension({
       id: "extensionId",
       manifest: {
         name: "test",

src/renderer/components/dock/__test__/log-resource-selector.test.tsx

@@ -44,8 +44,8 @@ const getFewPodsTabData = (): LogTabData => {
 
 describe("<LogResourceSelector />", () => {
   beforeEach(() => {
-    UserStore.getInstanceOrCreate();
-    ThemeStore.getInstanceOrCreate();
+    UserStore.createInstance();
+    ThemeStore.createInstance();
   });
 
   afterEach(() => {

src/renderer/components/layout/__test__/main-layout-header.test.tsx

@@ -16,7 +16,7 @@ const cluster: Cluster = new Cluster({
 
 describe("<MainLayoutHeader />", () => {
   beforeEach(() => {
-    ClusterStore.getInstanceOrCreate();
+    ClusterStore.createInstance();
   });
 
   afterEach(() => {

src/renderer/lens-app.tsx

@@ -25,7 +25,7 @@ export class LensApp extends React.Component {
   static async init() {
     catalogEntityRegistry.init();
     ExtensionLoader.getInstance().loadOnClusterManagerRenderer();
-    LensProtocolRouterRenderer.getInstanceOrCreate().init();
+    LensProtocolRouterRenderer.createInstance().init();
     bindProtocolAddRouteHandlers();
 
     window.addEventListener("offline", () => broadcastMessage("network:offline"));

src/renderer/utils/__tests__/storageHelper.test.ts

@@ -5,7 +5,7 @@ import { ClusterStore } from "../../../common/cluster-store";
 
 describe("renderer/utils/StorageHelper", () => {
   beforeEach(() => {
-    ClusterStore.getInstanceOrCreate();
+    ClusterStore.createInstance();
   });
 
   afterEach(() => {