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.