Added /healthz JSON response for heartbeat data. #1940

Author: JacobGo

src/node/app/health.ts

@@ -0,0 +1,43 @@
+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)
+    }
+
+    private alive(): Boolean {
+        const now = Date.now()
+        return (now - this.heart.lastHeartbeat < this.heart.heartbeatInterval)
+    }
+
+    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.alive()) ? 'alive' : 'expired',
+                lastHeartbeat: this.heart.lastHeartbeat
+
+            }
+        }
+
+        return result
+        
+    }
+}

src/node/entry.ts

@@ -7,6 +7,7 @@ import { ProxyHttpProvider } from "./app/proxy"
 import { StaticHttpProvider } from "./app/static"
 import { UpdateHttpProvider } from "./app/update"
 import { VscodeHttpProvider } from "./app/vscode"
+import { HealthHttpProvider } from "./app/health"
 import { Args, bindAddrFromAllSources, optionDescriptions, parse, readConfigFile, setDefaults } from "./cli"
 import { AuthType, HttpServer, HttpServerOptions } from "./http"
 import { loadPlugins } from "./plugin"
@@ -78,6 +79,7 @@ const main = async (args: Args, cliArgs: Args, configArgs: Args): Promise<void>
   httpServer.registerHttpProvider("/proxy", ProxyHttpProvider)
   httpServer.registerHttpProvider("/login", LoginHttpProvider, args.config!, envPassword)
   httpServer.registerHttpProvider("/static", StaticHttpProvider)
+  httpServer.registerHttpProvider("/healthz", HealthHttpProvider, httpServer.heart)
 
   await loadPlugins(httpServer, args)
 

src/node/http.ts

@@ -395,8 +395,8 @@ export abstract class HttpProvider {
  */
 export class Heart {
   private heartbeatTimer?: NodeJS.Timeout
-  private heartbeatInterval = 60000
-  private lastHeartbeat = 0
+  public heartbeatInterval = 60000
+  public lastHeartbeat = 0
 
   public constructor(private readonly heartbeatPath: string, private readonly isActive: () => Promise<boolean>) {}
 
@@ -457,7 +457,7 @@ export class HttpServer {
   private listenPromise: Promise<string | null> | undefined
   public readonly protocol: "http" | "https"
   private readonly providers = new Map<string, HttpProvider>()
-  private readonly heart: Heart
+  public readonly heart: Heart
   private readonly socketProvider = new SocketProxyProvider()
 
   /**
@@ -602,8 +602,9 @@ export class HttpServer {
   }
 
   private onRequest = async (request: http.IncomingMessage, response: http.ServerResponse): Promise<void> => {
-    this.heart.beat()
     const route = this.parseUrl(request)
+    if (route.providerBase !== '/healthz')
+      this.heart.beat()      
     const write = (payload: HttpResponse): void => {
       response.writeHead(payload.redirect ? HttpCode.Redirect : payload.code || HttpCode.Ok, {
         "Content-Type": payload.mime || getMediaMime(payload.filePath),