pm2.js

import config from './site-config.js'
import pm2 from 'pm2'
const instances = process.env.WEB_CONCURRENCY || -1
const maxMemory = process.env.WEB_MEMORY || 512

// NOTE TO SELF. Logs are located in .pm2/logs
pm2.connect(function () {
  pm2.start(
    {
      script: 'start.js',
      name: config.appName,
      exec_mode: 'cluster',
      watch: false,
      instances,
      max_memory_restart: maxMemory + 'M',
      log_date_format: 'YYYY-MM-DD HH:mm Z',
      log_file: 'combined.log',
      error_file: 'err.log',
      out_file: 'out.log',
      merge_logs: true,
      env: {
        NODE_ENV: 'production',
      },
    },
    function (err) {
      if (err) {
        return console.error(
          'Error while launching applications',
          err.stack || err
        )
      }

      console.log('PM2 and application has been succesfully started')

      // Display logs in standard output
      pm2.launchBus(function (err, bus) {
        if (err) console.log(err)
        console.log('[PM2] Log streaming started')

        bus.on('log:out', function (packet) {
          console.log('[App:%s] %s', packet.process.name, packet.data)
        })

        bus.on('log:err', function (packet) {
          console.error('[App:%s][Err] %s', packet.process.name, packet.data)
        })
      })
    }
  )
})