feat: Add healthz endpoints to api and frontend (powerhouse-inc#34)

README.md

@@ -36,3 +36,9 @@ To understand what is planned you can read and ask questions here:
 To install correct node version, we recommend that you use [nvm](https://github.com/nvm-sh/nvm). If you have `nvm` installed you can run `nvm install && nvm use` to automatically use the correct node version. The version is detected from the [.nvmrc](./.nvmrc).
 
 If you do not have a code editor setup, we recommend that you use [Visual Studio Code](https://code.visualstudio.com/) to get started. It is very beginner friendly and you can move on to something else down the road if you want to.
+
+## Health endpoints
+
+Both api and frontend have health endpoints that can be used to check if the service is up and running.
+
+See the respective descriptions in the [api](./api/README.md#health-endpoint) and [frontend](./frontend/README.md#health-endpoint) READMEs.

api/README.md

@@ -53,3 +53,7 @@ npx prisma studio
 ### Logging configuration
 
 The configuration is received from the `logger.config.ts` file at the root of the project. Adjust the file parameters to control the logger behaviour.
+
+## Health endpoint
+
+Endpoint available at `/healthz` path. Provides response if api is currently running and prisma (orm) is able to execute queries.

api/package.json

@@ -53,6 +53,7 @@
         "gql-query-builder": "^3.8.0",
         "graphql-request": "^5.2.0",
         "prisma": "^4.11.0",
-        "typescript": "^4.9.5"
+        "typescript": "^4.9.5",
+        "vitest-mock-extended": "^1.1.3"
     }
 }

api/src/__mocks__/database.ts

@@ -0,0 +1,11 @@
+import { PrismaClient } from '@prisma/client';
+import { beforeEach } from 'vitest';
+import { mockDeep, mockReset } from 'vitest-mock-extended';
+
+const prisma = mockDeep<PrismaClient>();
+
+beforeEach(() => {
+  mockReset(prisma);
+});
+
+export default prisma;

api/src/app.ts

@@ -2,19 +2,42 @@ import type { Express } from 'express';
 import express from 'express';
 import expressPlayground from 'graphql-playground-middleware-express';
 import { getChildLogger } from './logger';
+import prisma from './database';
 
 const logger = getChildLogger({ msgPrefix: 'APP' });
+const startupTime = new Date();
 
 export const createApp = (): Express => {
   logger.debug('Creating app');
   const app = express();
 
-  app.get('/', expressPlayground({
-    endpoint: '/api/graphql',
-    settings: {
-      'editor.theme': 'light',
-    },
-  }));
+  app.get('/healthz', async (_req, res) => {
+    try {
+      // TODO: after migration to postgres, do SELECT 1
+      await prisma.user.findFirst();
+    } catch (error) {
+      return res.status(500).json({
+        status: 'DB failed initialization check',
+        time: new Date(),
+        startupTime,
+      });
+    }
+    return res.json({
+      status: 'healthy',
+      time: new Date(),
+      startupTime,
+    });
+  });
+
+  app.get(
+    '/',
+    expressPlayground({
+      endpoint: '/api/graphql',
+      settings: {
+        'editor.theme': 'light',
+      },
+    }),
+  );
 
   return app;
 };

api/tests/auxilary.test.ts

@@ -1,6 +1,10 @@
-import { test, expect } from 'vitest';
+import {
+  test, expect, vi, describe,
+} from 'vitest';
 import { getJwtSecret, getJwtExpirationPeriod } from '../src/env/getters';
 import { restoreEnvAfterEach } from './helpers/env';
+import { ctx } from './helpers/server';
+import prisma from '../src/__mocks__/database';
 
 restoreEnvAfterEach();
 
@@ -34,3 +38,25 @@ test('Env: jwt expiration in seconds format', async () => {
   process.env.JWT_EXPIRATION_PERIOD = '3600';
   expect(getJwtExpirationPeriod()).toBe('1h');
 });
+
+describe('Healthz', () => {
+  vi.mock('../src/database');
+
+  test('healthz: returns 200', async () => {
+    prisma.user.findFirst.mockResolvedValueOnce({ id: '1', username: 'asdf', password: 'asdf' });
+    const url = `${ctx.baseUrl}/healthz`;
+    const res = await fetch(url);
+    expect(res.status).toBe(200);
+    const json: any = await res.json();
+    expect(json.status).toBe('healthy');
+  });
+
+  test('healthz: returns 500', async () => {
+    prisma.user.findFirst.mockRejectedValueOnce(new Error('test'));
+    const url = `${ctx.baseUrl}/healthz`;
+    const res = await fetch(url);
+    expect(res.status).toBe(500);
+    const json: any = await res.json();
+    expect(json.status).toBe('DB failed initialization check');
+  });
+});

api/tests/helpers/server.ts

@@ -6,10 +6,12 @@ import { createApp } from '../../src/app';
 
 interface TestContext {
   client: GraphQLClient;
+  baseUrl: string;
 }
 
 function getGraphqlTestContext() {
   let serverInstance: Server | null = null;
+  let baseUrl: string | null = null;
   return {
     async before() {
       const app = createApp();
@@ -19,10 +21,12 @@ function getGraphqlTestContext() {
         throw new Error('Unexpected server address format');
       }
       const { port } = serverAddress;
-      return new GraphQLClient(`http://0.0.0.0:${port}/graphql`);
+      baseUrl = `http://0.0.0.0:${port}`;
+      return { client: new GraphQLClient(`${baseUrl}/graphql`), baseUrl };
     },
     async after() {
       serverInstance?.close();
+      baseUrl = null;
     },
   };
 }
@@ -31,8 +35,9 @@ function createTestContext(): TestContext {
   const context = {} as TestContext;
   const graphqlTestContext = getGraphqlTestContext();
   beforeEach(async () => {
-    const client = await graphqlTestContext.before();
+    const { client, baseUrl } = await graphqlTestContext.before();
     context.client = client;
+    context.baseUrl = baseUrl;
   });
   afterEach(async () => {
     await graphqlTestContext.after();

frontend/README.md

@@ -13,3 +13,7 @@ Please refer to the root readme to learn more about general development setup.
 ## Production
 
 You can build application for production using `npm run build` and then locally preview production build via `npm run preview`.
+
+## Health endpoint
+
+Endpoint available at `/healthz` path. Provides response if frontend is currently running.

frontend/server/api/healthz.ts

@@ -0,0 +1,9 @@
+const startupTime = new Date()
+
+export default eventHandler(() => {
+  return {
+    status: 'healthy',
+    time: new Date(),
+    startupTime
+  }
+})