Added /healthz JSON response for heartbeat data. #1940 (#1984)

src/node/app/health.ts

@@ -0,0 +1,32 @@
+import * as http from "http"
+import { HttpCode, HttpError } from "../../common/http"
+import { HttpProvider, HttpResponse, Route, Heart, HttpProviderOptions } from "../http"
+
+/**
+ * Check the heartbeat.
+ */
+export class HealthHttpProvider extends HttpProvider {
+  public constructor(options: HttpProviderOptions, private readonly heart: Heart) {
+    super(options)
+  }
+
+  public async handleRequest(route: Route, request: http.IncomingMessage): Promise<HttpResponse> {
+    if (!this.authenticated(request)) {
+      if (this.isRoot(route)) {
+        return { redirect: "/login", query: { to: route.fullPath } }
+      }
+      throw new HttpError("Unauthorized", HttpCode.Unauthorized)
+    }
+
+    const result = {
+      cache: false,
+      mime: "application/json",
+      content: {
+        status: this.heart.alive() ? "alive" : "expired",
+        lastHeartbeat: this.heart.lastHeartbeat,
+      },
+    }
+
+    return result
+  }
+}