In this post, I'll show you how to package your NestJS backend and PostgreSQL database into Docker containers.

Step 1: Install Docker Desktop

Ensure Docker Desktop is installed and running. This tool will manage Docker containers and images.

Step 2: Create a Dockerfile in your Nest project

Assuming you've already set up NestJS with TypeORM as described in Setting Up a NestJS Project with TypeORM, create a Dockerfile in your project's root directory.

FROM node:16 
WORKDIR /backend/src/app 
COPY package*.json ./ 
RUN npm install 
COPY . . 
RUN npm run build 
EXPOSE 3000 
CMD [ "npm", "run" , "start:prod" ]  

Explanation of the Dockerfile:

• FROM node:16

  Base image with Node.js version 16.

• WORKDIR /backend/src/app

  Sets the working directory inside the container.

• COPY package.json ./** Copies package files for dependency installation.

• RUN npm install

  Installs dependencies.

• COPY . .

  Copies the application code.

• RUN npm run build

  Builds the application.

• EXPOSE 3000

  Exposes port 3000.

• CMD [ "npm", "run", "start" ]

  Runs the production server.

Step 3: Create docker-compose.yml in the Nest root directory

Create a docker-compose.yml file to manage multiple Docker containers.

version: '3.9'

services:
  nestapp:
    container_name: nest-backend
    image: backend:latest
    build: .
    ports:
      - 3000:3000
    environment:
      - TYPE=${TYPE}
      - HOST=${HOST}
      - USERNAME=${USERNAME}
      - PASSWORD=${PASSWORD}
      - PORT=${PORT}
      - DATABASE=${DATABASE}
    depends_on:
      - db
  db:
    container_name: db
    image: postgres:12
    ports:
      - 5432:5432
    environment:
      - POSTGRES_USER=${POSTGRES_USER}
      - POSTGRES_PASSWORD=${POSTGRES_PASSWORD}
      - POSTGRES_DB=${POSTGRES_DB}
    volumes:
      - pgdata:/var/lib/postgresql/data

volumes:
  pgdata: {}

Explanation of docker-compose.yml:

• version: '3.9'

  Docker Compose file format version.

• Services

  Defines nestapp and db services.

• nestapp

  NestJS backend service configuration.

  • container_name

    Names the container nest-backend.

  • image

    Uses the image backend:latest.

  • build

    Builds the image from the current directory (.).

  • ports

    Maps port 3000 of the container to port 3000 of the host.

  • environment

    Sets environment variables for the application using values from the host system.

  • depends_on

    Ensures nestapp starts after the db service.

• db

  PostgreSQL database service configuration.

  • container_name

    Names the container db.

  • image

    Uses the postgres:12 image.

  • ports

    Maps port 5432 of the container to port 5432 of the host.

  • environment

    Sets PostgreSQL environment variables using values from the host system.

  • volumes

    Mounts a Docker volume pgdata to persist PostgreSQL data.

• volumes

  Defines a volume for PostgreSQL data persistence.

Step 4: Create .env file

Create an .env file in your project's root directory to store environment variables.

# For backend
TYPE=postgres
HOST=db
USERNAME=postgres
PASSWORD=mypassword
PORT=5432
DATABASE=mydatabase

# For db
POSTGRES_USER=postgres
POSTGRES_PASSWORD=mypassword
POSTGRES_DB=mydatabase

Step 5: Build and run Docker containers

Execute the following command to build and start Docker containers:

docker compose up

Conclusion

This guide will help you get started with Dockerizing your NestJS application alongside a PostgreSQL database, enabling you to manage your application environment more efficiently.