chore: Add health check aware of infrastructure dependencies and conf…

…igure aws load-balancer accordingly

api/package.json

@@ -24,6 +24,7 @@
     "@nestjs/jwt": "^10.2.0",
     "@nestjs/passport": "^10.0.3",
     "@nestjs/platform-express": "^10.0.0",
+    "@nestjs/terminus": "^10.2.3",
     "@nestjs/typeorm": "^10.0.2",
     "@ts-rest/nest": "^3.51.0",
     "@types/multer": "1.4.12",

api/src/app.controller.ts

@@ -1,12 +1,28 @@
 import { Controller, Get } from '@nestjs/common';
-import { AppService } from './app.service';
+import {
+  HealthCheck,
+  HealthCheckService,
+  TypeOrmHealthIndicator,
+} from '@nestjs/terminus';
+import { ControllerResponse } from '@api/types/controller-response.type';
 
 @Controller()
 export class AppController {
-  constructor(private readonly appService: AppService) {}
+  constructor(
+    private readonly health: HealthCheckService,
+    private readonly db: TypeOrmHealthIndicator,
+  ) {}
 
-  @Get()
-  getHello(): string {
-    return this.appService.getHello();
+  @Get('/')
+  public root(): ControllerResponse {
+    return null;
+  }
+
+  @Get('/health')
+  @HealthCheck({ noCache: true })
+  public checkHealth(): ControllerResponse {
+    return this.health.check([
+      async () => this.db.pingCheck('database', { timeout: 1500 }),
+    ]);
   }
 }

api/src/app.module.ts

@@ -17,9 +17,13 @@ import * as path from 'path';
 import { CountriesModule } from '@api/modules/countries/countries.module';
 import { ProjectsModule } from '@api/modules/projects/projects.module';
 import { CustomProjectsModule } from '@api/modules/custom-projects/custom-projects.module';
+import { TerminusModule } from '@nestjs/terminus';
+
+const NODE_ENV = process.env.NODE_ENV;
 
 @Module({
   imports: [
+    TerminusModule.forRoot({ logger: NODE_ENV === 'test' ? false : true }),
     TsRestModule.register({
       validateRequestQuery: true,
       validateRequestBody: true,

api/test/integration/health/health.spec.ts

@@ -0,0 +1,46 @@
+import { TestManager } from 'api/test/utils/test-manager';
+
+describe('Health', () => {
+  let testManager: TestManager;
+
+  beforeAll(async () => {
+    testManager = await TestManager.createTestManager({ logger: false });
+  });
+
+  beforeEach(async () => {
+    await testManager.clearDatabase();
+  });
+
+  afterAll(async () => {
+    await testManager.close();
+  });
+
+  it("Should return the app's health status: OK", async () => {
+    // Given
+    // The app is running
+
+    // When
+    const { statusCode, body } = await testManager.request().get('/health');
+
+    // Then
+    expect(statusCode).toBe(200);
+    expect(body).toStrictEqual({
+      status: 'ok',
+      info: { database: { status: 'up' } },
+      error: {},
+      details: { database: { status: 'up' } },
+    });
+  });
+
+  it("Should return the app's health status: Unavailable", async () => {
+    // Given
+    // The app is running and the database becomes unavailable
+    await testManager.dataSource.destroy();
+
+    // When
+    const { statusCode } = await testManager.request().get('/health');
+
+    // Then
+    expect(statusCode).toBe(503);
+  });
+});

api/test/utils/test-manager.ts

@@ -1,6 +1,6 @@
 import { AppModule } from '@api/app.module';
 import { Test, TestingModule } from '@nestjs/testing';
-import { INestApplication } from '@nestjs/common';
+import { INestApplication, Logger } from '@nestjs/common';
 import { DataSource } from 'typeorm';
 
 import { logUserIn } from './user.auth';
@@ -50,7 +50,7 @@ export class TestManager {
     this.moduleFixture = moduleFixture;
   }
 
-  static async createTestManager() {
+  static async createTestManager(options: { logger?: Logger | false } = {}) {
     const moduleFixture = await Test.createTestingModule({
       imports: [AppModule],
     })
@@ -59,6 +59,10 @@ export class TestManager {
       .compile();
     const dataSource = moduleFixture.get<DataSource>(getDataSourceToken());
     const testApp = moduleFixture.createNestApplication();
+    if (options.logger !== undefined) {
+      // Has to be called before init. Otherwise it has no effect.
+      testApp.useLogger(options.logger);
+    }
     // TODO: Add global validation or App level Zod when decided what to use
     //testApp.useGlobalPipes(new ValidationPipe());
     await testApp.init();

client/src/app/health/route.ts

@@ -0,0 +1,23 @@
+export async function GET() {
+  try {
+    const res = await fetch(process.env.NEXT_PUBLIC_API_URL + "/health", {
+      cache: "no-cache",
+    });
+    if (res.status === 200) {
+      return new Response("OK", {
+        status: 200,
+        headers: { "Cache-Control": "max-age=5, must-revalidate" },
+      });
+    } else {
+      return new Response("KO", {
+        status: 503,
+        headers: { "Cache-Control": "max-age=5, must-revalidate" },
+      });
+    }
+  } catch (error) {
+    return new Response("KO", {
+      status: 503,
+      headers: { "Cache-Control": "max-age=5, must-revalidate" },
+    });
+  }
+}

infrastructure/modules/beanstalk/main.tf

@@ -149,6 +149,11 @@ locals {
       name      = "SSLCertificateArns"
       value     = var.acm_certificate.arn
     },
+    {
+      namespace = "aws:elasticbeanstalk:environment:process:default"
+      name      = "HealthCheckPath"
+      value     = "/health"
+    }
   ]
 }