Add Server Startup Hooks

[anthonyalayo]

Describe the feature you'd like to request

This feature has been requested for over 2 years now in this discussion thread with no response from Vercel: #15341

I belive @mschipperheyn described it very simply:

Nextjs should have subscribeable events for this that accept promises:

preStartup
postStartup
preShutdown
postShutdown

The basic task of initialization is such a pain. You should not have to optin to a custom server to be able to do this.

This feature is necessary since standalone mode does not work with custom servers. Being able to initialize a prism connection pool or telemetry at the start of an application is standard for use with API routes.

Describe the solution you'd like

Provide any sort of hook/function/subscribe-able event that developers can use to have code run once at server startup.

Describe alternatives you've considered

I have considered using a custom server to do this, but it does not work with standalone mode. Standalone ignores your custom server and generates its own.

[anthonyalayo]

Please do not bucket this under discussion -- this is a feature request. The associated discussion is here: #15341

[balazsorban44]

Hi, feature requests are converted to discussions as outlined in the contribution docs, as well as the issue template you filled out.

[jtlapp]

Wow this got punted without a response, neither here nor in the original discussion. Not a good look.

[puschie286]

Super basic feature - absolute necessary for every server application. Current solution with instrumentation is very unreliable.

I’m very surprised how nextjs could exist for almost 10 year without a “regular” server lifecycle.