Signal handling for node Express apps in Docker

index.js

const PORT = process.env.PORT || 8081
const HOST = process.env.HOST || 'localhost'

const app = express()
const server = app.listen(PORT, err => {
  if (err) {
    console.error(err)
    process.exit(1)
  }

  console.log(`Listening at http://${HOST}:${PORT}`)
})

const handleSignal = (signal, message) => {
  process.on(signal, () => {
    console.info(message)

    server.close(err => {
      if (err) {
        console.error(err)
        process.exit(1)
      }

      process.exit()
    })
  })
}

handleSignal('SIGINT', 'Received Ctrl-C, shutting down gracefully...')
handleSignal('SIGTERM', 'Container is stopping, shutting down gracefully...')