feat: implement health check endpoint

package.json

@@ -10,13 +10,15 @@
   },
   "dependencies": {
     "@nestjs/common": "^10.4.22",
+    "@nestjs/config": "^3.2.3",
     "@nestjs/core": "^10.4.22",
     "@nestjs/platform-express": "^10.4.22",
+    "@nestjs/typeorm": "^10.0.2",
     "@stellar/stellar-sdk": "^11.0.0",
     "pg": "^8.11.0",
     "reflect-metadata": "^0.2.2",
     "rxjs": "^7.8.2",
-    "typeorm": "^0.3.0"
+    "typeorm": "^0.3.20"
   },
   "devDependencies": {
     "@nestjs/cli": "^11.0.16",

src/app.module.ts

@@ -1,9 +1,10 @@
 import { Module } from '@nestjs/common';
 import { AppController } from './app.controller';
 import { AppService } from './app.service';
+import { HealthModule } from './health/health.module';
 
 @Module({
-  imports: [],
+  imports: [HealthModule],
   controllers: [AppController],
   providers: [AppService],
 })

src/database.providers.ts

@@ -0,0 +1,21 @@
+import { DataSource } from 'typeorm';
+
+export const databaseProviders = [
+  {
+    provide: 'DATA_SOURCE',
+    useFactory: async () => {
+      const dataSource = new DataSource({
+        type: 'postgres',
+        host: process.env.DB_HOST || 'localhost',
+        port: parseInt(process.env.DB_PORT) || 5432,
+        username: process.env.DB_USERNAME || 'postgres',
+        password: process.env.DB_PASSWORD || 'password',
+        database: process.env.DB_DATABASE || 'tradeflow',
+        entities: [`${__dirname}/**/*.entity{.ts,.js}`],
+        synchronize: process.env.NODE_ENV === 'development',
+      });
+
+      return dataSource.initialize();
+    },
+  },
+];

src/health/health.controller.ts

@@ -0,0 +1,40 @@
+import { Controller, Get, HttpStatus, HttpException, Inject } from '@nestjs/common';
+import { DataSource } from 'typeorm';
+
+@Controller()
+export class HealthController {
+  constructor(@Inject('DATA_SOURCE') private readonly dataSource: DataSource) {}
+
+  @Get('health')
+  async healthCheck() {
+    try {
+      const isConnected = this.dataSource.isInitialized;
+
+      if (isConnected) {
+        return {
+          status: 'ok',
+          database: 'up',
+          timestamp: new Date().toISOString(),
+        };
+      } else {
+        throw new HttpException(
+          {
+            status: 'error',
+            database: 'down',
+            timestamp: new Date().toISOString(),
+          },
+          HttpStatus.SERVICE_UNAVAILABLE,
+        );
+      }
+    } catch (error) {
+      throw new HttpException(
+        {
+          status: 'error',
+          database: 'down',
+          timestamp: new Date().toISOString(),
+        },
+        HttpStatus.SERVICE_UNAVAILABLE,
+      );
+    }
+  }
+}

src/health/health.module.ts

@@ -0,0 +1,9 @@
+import { Module } from '@nestjs/common';
+import { HealthController } from './health.controller';
+import { databaseProviders } from '../database.providers';
+
+@Module({
+  controllers: [HealthController],
+  providers: [...databaseProviders],
+})
+export class HealthModule {}

test-health.js

@@ -0,0 +1,32 @@
+// Simple test script to verify health endpoint
+const http = require('http');
+
+const options = {
+  hostname: 'localhost',
+  port: 3000,
+  path: '/health',
+  method: 'GET',
+  headers: {
+    'Content-Type': 'application/json'
+  }
+};
+
+const req = http.request(options, (res) => {
+  console.log(`Status Code: ${res.statusCode}`);
+  console.log(`Headers: ${JSON.stringify(res.headers, null, 2)}`);
+
+  let data = '';
+  res.on('data', (chunk) => {
+    data += chunk;
+  });
+
+  res.on('end', () => {
+    console.log('Response Body:', JSON.parse(data));
+  });
+});
+
+req.on('error', (error) => {
+  console.error('Error:', error.message);
+});
+
+req.end();