electron: allow accessing the metrics endpoint for performance analysis

packages/metrics/package.json

@@ -14,6 +14,9 @@
     {
       "frontend": "lib/browser/metrics-frontend-module",
       "backend": "lib/node/metrics-backend-module"
+    },
+    {
+      "backendElectron": "lib/electron-node/electron-metrics-backend-module"
     }
   ],
   "keywords": [

packages/metrics/src/electron-node/electron-metrics-backend-module.ts

@@ -0,0 +1,24 @@
+// *****************************************************************************
+// Copyright (C) 2023 STMicroelectronics and others.
+//
+// This program and the accompanying materials are made available under the
+// terms of the Eclipse Public License v. 2.0 which is available at
+// http://www.eclipse.org/legal/epl-2.0.
+//
+// This Source Code may also be made available under the following Secondary
+// Licenses when the conditions for such availability set forth in the Eclipse
+// Public License v. 2.0 are satisfied: GNU General Public License, version 2
+// with the GNU Classpath Exception which is available at
+// https://www.gnu.org/software/classpath/license.html.
+//
+// SPDX-License-Identifier: EPL-2.0 OR GPL-2.0-only WITH Classpath-exception-2.0
+// *****************************************************************************
+
+import { ContainerModule } from '@theia/core/shared/inversify';
+import { MetricsElectronTokenValidator } from './electron-token-validator';
+import { ElectronTokenValidator } from '@theia/core/lib/electron-node/token/electron-token-validator';
+
+export default new ContainerModule((bind, unbind, isBound, rebind) => {
+    bind(MetricsElectronTokenValidator).toSelf().inSingletonScope();
+    rebind(ElectronTokenValidator).to(MetricsElectronTokenValidator);
+});

packages/metrics/src/electron-node/electron-token-validator.ts

@@ -0,0 +1,37 @@
+// *****************************************************************************
+// Copyright (C) 2023 STMicroelectronics and others.
+//
+// This program and the accompanying materials are made available under the
+// terms of the Eclipse Public License v. 2.0 which is available at
+// http://www.eclipse.org/legal/epl-2.0.
+//
+// This Source Code may also be made available under the following Secondary
+// Licenses when the conditions for such availability set forth in the Eclipse
+// Public License v. 2.0 are satisfied: GNU General Public License, version 2
+// with the GNU Classpath Exception which is available at
+// https://www.gnu.org/software/classpath/license.html.
+//
+// SPDX-License-Identifier: EPL-2.0 OR GPL-2.0-only WITH Classpath-exception-2.0
+// *****************************************************************************
+
+import { injectable, postConstruct } from '@theia/core/shared/inversify';
+import { ElectronTokenValidator } from '@theia/core/lib/electron-node/token/electron-token-validator';
+import { IncomingMessage } from 'http';
+import { MetricsBackendApplicationContribution } from '../node/metrics-backend-application-contribution';
+import { MaybePromise } from '@theia/core';
+
+@injectable()
+export class MetricsElectronTokenValidator extends ElectronTokenValidator {
+    @postConstruct()
+    protected override init(): void {
+        super.init();
+    }
+
+    override allowWsUpgrade(request: IncomingMessage): MaybePromise<boolean> {
+        return this.allowRequest(request);
+    }
+
+    override allowRequest(request: IncomingMessage): boolean {
+        return request.url === MetricsBackendApplicationContribution.ENDPOINT || super.allowRequest(request);
+    }
+}

packages/metrics/src/node/metrics-backend-application-contribution.ts

@@ -24,14 +24,15 @@ import { MetricsContribution } from './metrics-contribution';
 
 @injectable()
 export class MetricsBackendApplicationContribution implements BackendApplicationContribution {
+    static ENDPOINT = '/metrics';
     constructor(
         @inject(ContributionProvider) @named(MetricsContribution)
         protected readonly metricsProviders: ContributionProvider<MetricsContribution>
     ) {
     }
 
     configure(app: express.Application): void {
-        app.get('/metrics', (req, res) => {
+        app.get(MetricsBackendApplicationContribution.ENDPOINT, (req, res) => {
             const lastMetrics = this.fetchMetricsFromProviders();
             res.send(lastMetrics);
         });