**Course Title:** Mastering NestJS: Building Scalable Server-Side Applications **Section Title:** Deployment and CI/CD Pipelines **Topic:** Preparing NestJS applications for production deployment In this topic, we will cover the essential steps to prepare your NestJS application for production deployment. This includes setting up a production-ready environment, configuring your application for scalability, and implementing monitoring and logging. ### 1. Setting up a Production-Ready Environment To prepare your NestJS application for production, you need to set up a production-ready environment. This involves creating a separate environment file for production and configuring your application to use it. **Step 1: Create a production environment file** Create a new file called `environment.prod.ts` in the `src/environments` directory. This file will contain the production-specific configuration for your application. ```typescript // src/environments/environment.prod.ts export const environment = { production: true, apiEndpoint: 'https://api.example.com', database: { type: 'postgres', host: 'localhost', port: 5432, username: 'username', password: 'password', database: 'database', }, }; ``` **Step 2: Configure your application to use the production environment** In your `main.ts` file, import the production environment file and use it to configure your application. ```typescript // main.ts import { NestFactory } from '@nestjs/core'; import { AppModule } from './app.module'; import { environment } from './environments/environment.prod'; async function bootstrap() { const app = await NestFactory.create(AppModule, { cors: { origin: ['http://localhost:4200'], methods: 'GET,HEAD,PUT,PATCH,POST,DELETE', preflightContinue: false, optionsSuccessStatus: 204, }, }); app.setGlobalPrefix('api'); app.enableCors(); await app.listen(environment.apiEndpoint); } bootstrap(); ``` ### 2. Configuring your application for scalability To configure your application for scalability, you need to use a load balancer and a containerization platform like Docker. **Step 1: Create a Dockerfile** Create a new file called `Dockerfile` in the root directory of your project. This file will contain the instructions for building your Docker image. ```dockerfile # Dockerfile FROM node:14 WORKDIR /app COPY package*.json ./ RUN npm install COPY . . RUN npm run build EXPOSE 3000 CMD ["node", "src/main.ts"] ``` **Step 2: Build and push your Docker image** Build your Docker image using the following command: ```bash docker build -t my-nestjs-app . ``` Push your Docker image to a containerization platform like Docker Hub: ```bash docker tag my-nestjs-app:latest <your-docker-hub-username>/my-nestjs-app:latest docker push <your-docker-hub-username>/my-nestjs-app:latest ``` ### 3. Implementing monitoring and logging To implement monitoring and logging, you can use a service like New Relic or Prometheus. **Step 1: Install the New Relic agent** Install the New Relic agent using npm: ```bash npm install @newrelic/node ``` **Step 2: Configure the New Relic agent** Configure the New Relic agent in your `main.ts` file: ```typescript // main.ts import { NestFactory } from '@nestjs/core'; import { AppModule } from './app.module'; import { environment } from './environments/environment.prod'; import { NewRelicAgent } from '@newrelic/node'; async function bootstrap() { const app = await NestFactory.create(AppModule, { cors: { origin: ['http://localhost:4200'], methods: 'GET,HEAD,PUT,PATCH,POST,DELETE', preflightContinue: false, optionsSuccessStatus: 204, }, }); app.setGlobalPrefix('api'); app.enableCors(); const newRelicAgent = new NewRelicAgent({ licenseKey: 'YOUR_LICENSE_KEY', }); newRelicAgent.start(); await app.listen(environment.apiEndpoint); } bootstrap(); ``` ### Conclusion In this topic, we covered the essential steps to prepare your NestJS application for production deployment. We set up a production-ready environment, configured our application for scalability, and implemented monitoring and logging. We also used a service like New Relic to monitor and log our application. ### What's next? In the next topic, we will cover deploying NestJS applications to cloud platforms like AWS and Heroku. ### Leave a comment or ask for help If you have any questions or need help with any of the steps in this topic, please leave a comment below.