HttpServer working with GET routes

Web/WebSocket/websocket/server/src/health/HealthCheck.ts

@@ -0,0 +1,13 @@
+import type {HealthStatus} from './IHealthCheck';
+
+export default class HealthCheck {
+  public checkHealth(): HealthStatus {
+    return {
+      status: 'ok',
+      environment: 'development',
+      app: 'websocket-server',
+      version: '0.0.1',
+      zone: 'us-central1'
+    };
+  }
+}

Web/WebSocket/websocket/server/src/health/HealthCheckRoute.ts

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+import type {Request, Response} from 'express';
+import type IRoute from '../net/http/IRoutes';
+import IHealthCheck from './IHealthCheck';
+
+export default class HealthCheckRoute implements IRoute {
+  private readonly _healthCheck: IHealthCheck;
+
+  constructor(healthCheck: IHealthCheck) {
+    this._healthCheck = healthCheck;
+  }
+
+  public getGETRoutes() {
+    console.log('[HealthCheckRoute] getGETRoutes called');
+    const routes = {
+      '/ok.html': (req, res) => this.externalReadiness.call(this, req, res),
+      '/ping': (req, res) => this.ping.call(this, req, res)
+    };
+    console.log('[HealthCheckRoute] returning routes:', Object.keys(routes));
+    return routes;
+  }
+
+  public getPOSTRoutes() {
+    return {};
+  }
+
+  public getPUTRoutes() {
+    return {};
+  }
+
+  public getPATCHRoutes() {
+    return {};
+  }
+
+  public getDELETERoutes() {
+    return {};
+  }
+
+  private externalReadiness(_req: Request, res: Response) {
+    console.log('[HealthCheckRoute] External readiness');
+    res.setHeader('Cache-Control', 'public, max-age=0, no-cache, no-store');
+
+    try {
+      const result = this._healthCheck.checkHealth();
+
+      if (!result || !result.status) {
+        return res.status(500).end();
+      }
+
+      switch (result.status) {
+        case 'ok':
+        case 'draining':
+        case 'draining2':
+        case 'disabled':
+          return res.status(200).json(result);
+        case 'starting':
+        case 'drained':
+        case 'stopped':
+          return res.status(503).json(result);
+        default:
+          return res.status(500).json(result);
+      }
+    } catch {
+      return res.status(500).end();
+    }
+  }
+
+  private ping(_req: Request, res: Response) {
+    console.log('[HealthCheckRoute] Ping handler called from [%s]', _req.ip);
+
+    res.status(200).send({status: 'pong'}).end();
+  }
+}

Web/WebSocket/websocket/server/src/health/IHealthCheck.ts

@@ -0,0 +1,11 @@
+export type HealthStatus = {
+  status: 'ok' | 'draining' | 'draining2' | 'disabled' | 'starting' | 'drained' | 'stopped';
+  environment: string;
+  app: string;
+  version: string;
+  zone: string;
+};
+
+export default interface IHealthCheck {
+  checkHealth(): HealthStatus;
+}