Dockerizing Node.js: Easily Create a Development Environment
Using Docker can significantly simplify development and deployment processes. Especially during active development, containerization offers numerous advantages.
In this tutorial, we’ll show you how to set up a development environment for a Node.js application using Docker and Docker Compose.
Using containers in development brings several benefits:
- Consistent Environments: You can choose the languages and dependencies for your project without worrying about system conflicts.
- Isolated Environments: This makes debugging easier and simplifies onboarding for new team members.
- Portability: You can easily package and share your code.
Step 1: Clone the Project and Adjust Dependencies
The first step is to clone the project and adjust the dependencies in the `package.json` file. Add `nodemon` as a `devDependency` to enable automatic restarts during development.
git clone https://github.com/do-community/nodejs-mongo-mongoose.git node_project
cd node_project
nano package.json
“dependencies”: {
“ejs”: “^2.6.1”,
“express”: “^4.16.4”,
“mongoose”: “^5.4.10”
},
“devDependencies”: {
“nodemon”: “^1.18.10”
}
Step 2: Configure the Application for Containers
Adjust your application to prepare it for working with containers. Refactor the code to use environment variables and dynamically set up the database connection.
nano app.js
const port = process.env.PORT || 8080;
app.listen(port, function () {
console.log(`Example app listening on ${port}!`);
});
Step 3: Adjust Database Connection Settings
Make your database connection more robust by adding code that handles cases where the application cannot connect to the database.
nano db.js
const {
MONGO_USERNAME,
MONGO_PASSWORD,
MONGO_HOSTNAME,
MONGO_PORT,
MONGO_DB
} = process.env;
const options = {
useNewUrlParser: true,
reconnectTries: Number.MAX_VALUE,
reconnectInterval: 500,
connectTimeoutMS: 10000,
};
const url = `mongodb://${MONGO_USERNAME}:${MONGO_PASSWORD}@${MONGO_HOSTNAME}:${MONGO_PORT}/${MONGO_DB}?authSource=admin`;
mongoose.connect(url, options).then( function() {
console.log(‘MongoDB is connected’);
})
.catch( function(err) {
console.log(err);
});
Step 4: Define Services with Docker Compose
Define the services with Docker Compose by creating the `docker-compose.yml` file with the definitions for your services.
nano docker-compose.yml
version: ‘3’
services:
nodejs:
build:
context: .
dockerfile: Dockerfile
image: nodejs
container_name: nodejs
restart: unless-stopped
env_file: .env
environment:
– MONGO_USERNAME=$MONGO_USERNAME
– MONGO_PASSWORD=$MONGO_PASSWORD
– MONGO_HOSTNAME=db
– MONGO_PORT=$MONGO_PORT
– MONGO_DB=$MONGO_DB
ports:
– “80:8080”
volumes:
– .:/home/node/app
– node_modules:/home/node/app/node_modules
networks:
– app-network
command: ./wait-for.sh db:27017 — /home/node/app/node_modules/.bin/nodemon app.js
db:
image: mongo:4.1.8-xenial
container_name: db
restart: unless-stopped
env_file: .env
environment:
– MONGO_INITDB_ROOT_USERNAME=$MONGO_USERNAME
– MONGO_INITDB_ROOT_PASSWORD=$MONGO_PASSWORD
volumes:
– dbdata:/data/db
networks:
– app-network
networks:
app-network:
driver: bridge
volumes:
dbdata:
node_modules:
Step 5: Test the Application
Test your application by creating the containers with the `docker-compose up` command and checking if data persistence works.
Conclusion
By containerizing your Node.js application with Docker, you’ve created a flexible and portable development environment. You can now develop and deploy your code independently of the underlying infrastructure.
This tutorial provides a solid foundation for getting started with application development in containerized environments. It is recommended to explore further resources to deepen your knowledge of Docker and containerization. Dockerizing Node.js: Easily Create a Development Environment
