Gidgethub router created on each request, which leads to OOM issues

[joshuadavidthomas]

Upstream creates the gidgethub routing on each request, which leads to a cascading situation as found via Memray:

This was causing memory consumption to grow out of control until the process was restarted via max_requests or OOM:

Only instantiate the router once, on init should fix it.

Originally posted by @ewdurbin in psf/clabot#10

[joshuadavidthomas]

The benefits of other people using the library 😆 because I'm pretty sure our internal GitHub app has been having similar issues but I've been too busy/lazy to figure out why.

Looks like a relatively quick and easy fix, need to get this in asap.

[ewdurbin]

Oh hm, seems I didn't go deep enough. After this patch I'm still seeing leaks via

[ewdurbin]

@joshuadavidthomas this is my (now actually verified/validated) fix: psf/clabot#11

[joshuadavidthomas]

LOL, that's much simpler and better than the singleton road I was starting down. I'll add it in, and probably add pytest-memray and some memory specific tests to verify.