Detected a Phoenix app with Dockerfile specified in fly.toml

Recently our review app deploys started failing, seemingly due to a change in how flyctl detects the app type. It’s a Phoenix app with a Dockerfile in the root folder, and flyctl went from auto-detecting the Dockerfile to thinking it’s a Phoenix app (it is, but we don’t have elixir build tools in the deploy env, and we need to us our Dockerfile.)

I see the comment in the code about detecting frameworks first because the Dockerfile might not be what we want to deploy, but this error persists even after adding dockerfile = "Dockerfile" under the [build] section of the fly.toml file. Am I misunderstanding what that config option is for? App Configuration (fly.toml) · Fly Docs

Passing the --dockerfile option into flyctl seems to work, so I do have a path forward by patching the GitHub Action we’re using, but I wanted to get some clarity as well to better understand how this part of the config is supposed to work.

You’re right - this is a regression we should fix. We’ll look into it and post back here. How are you using launch in your CI?

Thanks for the reply, @jsierles!

We’re using our fork of the fly-review-apps GitHub action. Here’s the source after I modified it to pass the --dockerfile arg as a workaround: fly-pr-review-apps/ at main · revelrylabs/fly-pr-review-apps · GitHub.