Thruster+Rails 8+Grape+Falcon

[code-bunny]

Greetings,

For lack of a better place to ask, I am looking to switch my main Grape API that is mounted on Rails 8 (where the admin for said API lives on an engine) over from Puma to Falcon. We've had Falcon running in prod for a few years on a micro service, but not on a few application yet.

So is Falcon + Rails 8 + Postgres via ActiveRecord a-ok now? Do I need some concurrent PG gem like we did in the Goliath days?

Should we mount the app with Falcon only or does it play well with Thruster? Any downsides.

Also as an aside the documentation has preload "preload.rb" outside the service hostname do` block. Which will be a wee bit confusing for newcomers.

[ioquatix]

Also as an aside the documentation has preload "preload.rb" outside the service hostname do` block. Which will be a wee bit confusing for newcomers.

That is a documentation bug. Thanks for calling it out.

Fixed in c56cf4d

[ioquatix]

So is Falcon + Rails 8 + Postgres via ActiveRecord a-ok now? Do I need some concurrent PG gem like we did in the Goliath days?

Yes, this combination is 100% compatible with Falcon. Of course, you should still test things thoroughly.

Should we mount the app with Falcon only or does it play well with Thruster? Any downsides.

I have not had anyone report any issues, but I also don't know if people are using it or not. Please report back your experiences if you decided to try it out.

[code-bunny]

So it's been up for 2 days now and around two million requests so far without incident on Thurster+Falcon. Initially I was worried there was a memory leak as it claimed from 440 MB RAM to 1 GB RAM after switching to Falcon, but it seems steady there. The main point of concern just now is how big our database pool should be. I've gave it a pool of 20. But I am unsure if there is a better way to work this out. On Puma we went for 3 and just autoscaled from 2-32 instances. It seems the single Falcon can happily handle more RRPM (More often than not for requests for /etc/passwd :p)

We do have very good automated test coverage and tooling to report issues so I am not so worried about weirdness outside of Rails basically being a wrapper for a Grape API.