Healthcheck fails with Kamal 2

[kaka-ruto]

It does not seem to work with Kamal 2 - I get this error on deploy basecamp/thruster#42 (comment)

I tested with the endpoint pointing to /up and /healthcheck

But if I comment the mount, kamal deploy works well

[kaka-ruto]

I think the issue I found is if any of the checks fails, you will not know that it was the cause, it just let's Kamal handle the error reporting as best as it understands - without context from Allgood.

Will be very helpful if the failing healthcheck will be passed onto kamal for reporting

[rameerez]

@kaka-ruto thanks for reporting! I'm testing this in a Rails 8.0.0.rc1 app using Kamal 2.2.2 right now, with the default allgood config, and I think I know why it failed for you by default.

Apparently, in Rails 8 ActiveRecord::Base.connection.active? returns false even for a healthy ActiveRecord connection, if it didn't .connect! before (lazy connection). It will do that even for a connection that is able to read and write to DB in another check (e.g.: ActiveRecord::Base.connection.execute("SELECT 1").any? succeeds)

This was the very first test in the suggested allgood default config in the README, and it fails by default now in Rails 8+. I will edit it.

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RE: Kamal reading the allgood error -- unfortunately, HTTP codes is as much as I can return from allgood. 200 OK if all tests were healthy, 503 otherwise. I could add more semantics by returning a JSON payload with it, or a similar solution, but I'm afraid Kamal only reads the HTTP headers, and we'd need to PR some mechanism for Kamal to pick up on that payload and display it in the kamal deploy logs

Not sure how to proceed other than improving the first default test from the README and adding a warning for Kamal users. Do you have any ideas?

[kaka-ruto]

Hi @rameerez , thanks for the check!

Yeah, it's a two way solution isn't it - Kamal needs a protocol of some sort to accept healthcheck payloads, and I doubt that that's the team direction at the moment.

I think for now the documentation update will suffice. Let's see if Kamal first comes up with a mechanism to accept healthcheck payloads of some sort.

[rameerez]

@kaka-ruto thanks for the follow up! I've just improved the docs a bit more with more explicit mentions to Kamal. Hope this is enough! Closing this issue for now, thanks again for reporting!