🚀 Feature Proposal

Currently while fastify is shutting down, all APIs returns 503.
I would like to make this behaviour configurable.

Motivation

In Kubernetes, when a deployment is updated, the process receives a SIGTERM. After that, your container continues to receive incoming requests. With the current behaviour all those responses are 503, even if the process is able to serve them.

So, I cannot directly attach the SIGTERM event to fastify.close method.

Example

const fastify = require('fastify')({ returns503OnClose: false }) // default true

The changes involve those lines:

where the router.closeRoutes() is done only if the flag returns503OnClose is set to true.

NB: According to node documentation the callback will be called only when all connections are closed, so no requests are discarded.

Edit:

old conversation #886