backend-app-api: flip logic of health service

Signed-off-by: Vincenzo Scamporlino <vincenzos@spotify.com>

packages/backend-defaults/src/entrypoints/health/healthServiceFactory.test.ts

@@ -22,7 +22,13 @@ describe('DefaultHealthService', () => {
       const service = new DefaultHealthService({
         lifecycle: mockServices.rootLifecycle.mock(),
       });
-      await expect(service.getReadiness()).resolves.toEqual({ status: 503 });
+      await expect(service.getReadiness()).resolves.toEqual({
+        status: 503,
+        payload: {
+          message: 'Backend has not started yet',
+          status: 'error',
+        },
+      });
     });
 
     it('should return 200 if the server has started', async () => {
@@ -33,7 +39,7 @@ describe('DefaultHealthService', () => {
       );
 
       const service = new DefaultHealthService({
-        lifecycle: mockServices.rootLifecycle.mock(),
+        lifecycle,
       });
 
       mockServerStartedFn();
@@ -63,6 +69,10 @@ describe('DefaultHealthService', () => {
       mockServerStoppedFn();
       await expect(service.getReadiness()).resolves.toEqual({
         status: 503,
+        payload: {
+          message: 'Backend has not started yet',
+          status: 'error',
+        },
       });
     });
   });

packages/backend-defaults/src/entrypoints/health/healthServiceFactory.ts

@@ -37,6 +37,7 @@ export class DefaultHealthService implements HealthService {
   async getLiveness(): Promise<{ status: number; payload?: any }> {
     return { status: 200, payload: { status: 'ok' } };
   }
+
   async getReadiness(): Promise<{ status: number; payload?: any }> {
     if (!this.#isRunning) {
       return {

packages/backend-defaults/src/entrypoints/rootHttpRouter/createHealthRouter.ts

@@ -0,0 +1,42 @@
+import { HealthService } from '@backstage/backend-plugin-api';
+
+/*
+ * Copyright 2024 The Backstage Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import Router from 'express-promise-router';
+import { Request, Response } from 'express';
+
+export function createHealthRouter(options: { health: HealthService }) {
+  const router = Router();
+
+  router.get(
+    '.backstage/health/v1/readiness',
+    async (_request: Request, response: Response) => {
+      const { status, payload } = await options.health.getReadiness();
+      response.status(status).json(payload);
+    },
+  );
+
+  router.get(
+    '.backstage/health/v1/liveness',
+    async (_request: Request, response: Response) => {
+      const { status, payload } = await options.health.getLiveness();
+      response.status(status).json(payload);
+    },
+  );
+
+  return router;
+}

packages/backend-defaults/src/entrypoints/rootHttpRouter/rootHttpRouterServiceFactory.ts

@@ -29,6 +29,7 @@ import {
   readHttpServerOptions,
 } from './http';
 import { DefaultRootHttpRouter } from './DefaultRootHttpRouter';
+import { createHealthRouter } from './createHealthRouter';
 
 /**
  * @public
@@ -41,6 +42,7 @@ export interface RootHttpRouterConfigureContext {
   config: RootConfigService;
   logger: LoggerService;
   lifecycle: LifecycleService;
+  healthRouter: RequestHandler;
   applyDefaults: () => void;
 }
 
@@ -75,8 +77,9 @@ export const rootHttpRouterServiceFactory = createServiceFactory(
       config: coreServices.rootConfig,
       rootLogger: coreServices.rootLogger,
       lifecycle: coreServices.rootLifecycle,
+      health: coreServices.health,
     },
-    async factory({ config, rootLogger, lifecycle }) {
+    async factory({ config, rootLogger, lifecycle, health }) {
       const { indexPath, configure = defaultConfigure } = options ?? {};
       const logger = rootLogger.child({ service: 'rootHttpRouter' });
       const app = express();
@@ -84,6 +87,8 @@ export const rootHttpRouterServiceFactory = createServiceFactory(
       const router = DefaultRootHttpRouter.create({ indexPath });
       const middleware = MiddlewareFactory.create({ config, logger });
       const routes = router.handler();
+
+      const healthRouter = createHealthRouter({ health });
       const server = await createHttpServer(
         app,
         readHttpServerOptions(config.getOptionalConfig('backend')),
@@ -98,11 +103,13 @@ export const rootHttpRouterServiceFactory = createServiceFactory(
         config,
         logger,
         lifecycle,
+        healthRouter,
         applyDefaults() {
           app.use(middleware.helmet());
           app.use(middleware.cors());
           app.use(middleware.compression());
           app.use(middleware.logging());
+          app.use(healthRouter);
           app.use(routes);
           app.use(middleware.notFound());
           app.use(middleware.error());

packages/backend-plugin-api/api-report.md

@@ -335,7 +335,18 @@ export type ExtensionPoint<T> = {
 export type ExtensionPointConfig = CreateExtensionPointOptions;
 
 // @public (undocumented)
-export interface HealthService {}
+export interface HealthService {
+  // (undocumented)
+  getLiveness(): Promise<{
+    status: number;
+    payload?: any;
+  }>;
+  // (undocumented)
+  getReadiness(): Promise<{
+    status: number;
+    payload?: any;
+  }>;
+}
 
 // @public
 export interface HttpAuthService {

packages/backend-plugin-api/src/services/definitions/HealthService.ts

@@ -17,4 +17,7 @@
 /**
  * @public
  */
-export interface HealthService {}
+export interface HealthService {
+  getLiveness(): Promise<{ status: number; payload?: any }>;
+  getReadiness(): Promise<{ status: number; payload?: any }>;
+}

packages/backend-test-utils/src/next/services/mockServices.ts

@@ -20,11 +20,11 @@ import {
   HostDiscovery,
   discoveryServiceFactory,
 } from '@backstage/backend-defaults/discovery';
+import { healthServiceFactory } from '@backstage/backend-defaults/health';
 import { httpRouterServiceFactory } from '@backstage/backend-defaults/httpRouter';
 import { lifecycleServiceFactory } from '@backstage/backend-defaults/lifecycle';
 import { loggerServiceFactory } from '@backstage/backend-defaults/logger';
 import { permissionsServiceFactory } from '@backstage/backend-defaults/permissions';
-import { rootHealthServiceFactory } from '@backstage/backend-defaults/rootHealth';
 import { rootHttpRouterServiceFactory } from '@backstage/backend-defaults/rootHttpRouter';
 import { rootLifecycleServiceFactory } from '@backstage/backend-defaults/rootLifecycle';
 import { schedulerServiceFactory } from '@backstage/backend-defaults/scheduler';
@@ -345,6 +345,14 @@ export namespace mockServices {
     }));
   }
 
+  export namespace health {
+    export const factory = healthServiceFactory;
+    export const mock = simpleMock(coreServices.health, () => ({
+      getLiveness: jest.fn(),
+      getReadiness: jest.fn(),
+    }));
+  }
+
   export namespace httpRouter {
     export const factory = httpRouterServiceFactory;
     export const mock = simpleMock(coreServices.httpRouter, () => ({
@@ -384,14 +392,6 @@ export namespace mockServices {
     }));
   }
 
-  export namespace rootHealth {
-    export const factory = rootHealthServiceFactory;
-    export const mock = simpleMock(coreServices.health, () => ({
-      getLiveness: jest.fn(),
-      getReadiness: jest.fn(),
-    }));
-  }
-
   export namespace rootLifecycle {
     export const factory = rootLifecycleServiceFactory;
     export const mock = simpleMock(coreServices.rootLifecycle, () => ({