Given the simple service:

'use strict'

const fastify = require('fastify')({
  logger: { level: 'debug' },
  keepAliveTimeout: 60000
})

process.on('SIGINT', () => {
  fastify.close(() => {
    process.exit()
  })
})

fastify.route({
  path: '/',
  method: 'GET',
  handler (req, res) {
    res.send({ hello: 'world' })
  }
})

fastify.listen(8000)

We can start the server and then issue the following request to it:

GET / HTTP/1.1
connection: keep-alive
keep-alive: timeout=30, max=100

Subsequently, we send SIGINT to the server to indicate we want it to shutdown. At this point, we will see that the server does not shutdown before the keep-alive has completed. Our tests show that new connections are not possible, and re-usage of the existing connection should be met with a 503: https://github.com/fastify/fastify/blob/93fe532986b96ae28a087b2ec385a8abb16cce55/test/close.test.js

What we do not seem to have is a forceful termination of those open connections. I recognize that the spec says:

A host may keep an idle connection open for longer than timeout seconds, but the host should attempt to retain a connection for at least timeout seconds.
https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Keep-Alive

But when we are shutting down, we usually don't want to do that.

I think our fastify.close method is directly mapped to the avvio close method. If we want to support forceful connection draining, would we do it here?: