PM2

Find code examples for this guide on GitHub.

Initial setup

Generate an ecosystem.config.js file.

pm2 init

Modify it to your needs. Something like this.

module.exports = {
  apps : [{
    script: 'index.js',
    watch: '.'
  }]
};

Your index.js file should look something like this.

// index.js
const PORT = process.env.PORT || 3000
const http = require('http')
const server = http.createServer((req, res) => {
  res.statusCode = 200;
  res.setHeader('Content-Type', 'text/plain');
  res.end(`Hello ${process.env.HELLO}`)
});

server.listen(PORT, () => {
  console.log(`Server running on port:${PORT}/`);
});

Run dotenvx

Add @dotenvx/dotenvx and pm2 as dependencies.

npm install @dotenvx/dotenvx --save
npm install pm2 --save

Then, in your package.json, modify your start script.

{
  "scripts": {
    "start": "dotenvx run -- pm2-runtime start ecosystem.config.js --env production"
  },
  "dependencies": {
    "@dotenvx/dotenvx": "^1.48.4",
    "pm2": "^5.3.0"
  }
}

Create a .env file in the root of your project.

# .env
HELLO="World"

Inject your env using your start script — which is using dotenvx and pm2.

npm start

Your app will say Hello World. That covers local development. Let's solve for production next.

Add production environment

Create a .env.production file in the root of your project.

# .env.production
HELLO="production"

Modify your start script to load your .env.production file.

{
  "scripts": {
    "start": "dotenvx run -f .env.production -- pm2-runtime start ecosystem.config.js --env production"
  },
  ...
}

Your app will say Hello production, simulating production.