dinker VS dockerfile-rails

(Self plug) I had the same thoughts as the author, and made this: https://github.com/andrewbaxter/dinker . Like stated in the article, if you're doing rust or go all you want is to dump the binary in the image. There's no reason to do the build inside the docker vm in that case, and it's super fast, and only uses dumb filesystem access - no daemons like docker, weird wip container managers like buildah, etc.

Self hoisting here, I put this together to make it easier to generate single (extra) layer docker images without needing a docker agent, capabilities, chroot, etc: https://github.com/andrewbaxter/dinker

Caveat: it doesn't work on Fly.io. They seem to be having some issue with OCI manifests: https://github.com/containers/skopeo/issues/1881 . They're also having issues with new docker versions pushing from CI: https://community.fly.io/t/deploying-to-fly-via-github-actio... ... the timing of this post seems weird.

FWIW the article says

> create a Docker image, also known as an OCI image

I don't think this is quite right. From my investigation, Docker and OCI images are basically content addressed trees, starting with a root manifest that points to other files and their hashes (root -> images -> layers -> layer configs + files). The OCI manifests and configs are separate to Docker manifests and configs and basically Docker will support both side by side.

If you want to automatically generate Dockerfiles for more versions of Rails (not just the latest) that detect OS packages that need to be installed from gems present in your Gemfile, check out https://github.com/fly-apps/dockerfile-rails

You can install it in your rails app by running:

1. bundle add dockerfile-rails

2. rails g dockerfile

> I felt bad

Don't. I can honestly say that I didn't write this post targeting HN. I'll go further... this post wasn't meant for people who are unlikely to use https://github.com/fly-apps/dockerfile-rails#overview. I recently added some features to that gem whose usage may not be intuitively obvious. I wrote this post to explain some of the motivation for those features.

I don't know how to mark posts as not intended for HN (and truth be told, if there was such a feature, I'd be inclined to overuse it). I don't know where else I should have posted this content, but I'm not sure I would be inclined to move it. In any case, this post, as written, serves a purpose for me. Somebody not you and not me felt it belonged here. We can both second guess that decision. Either way, there is no reason for either of us to feel bad.

Did you try migrating with this guide? https://fly.io/docs/rails/getting-started/migrate-from-herok...

The issues you ran into with older versions of Rails was probably because the Dockerfile that `fly launch` generated was for new versions of Rails. We switched to https://github.com/rubys/dockerfile-rails to streamline Dockerfile generation and support older versions of Rails.

If you try it again and run into issues you can open an issue at https://github.com/rubys/dockerfile-rails/issues or post in https://community.fly.io and somebody will help get that sorted out.

The more versions of Rails we can deploy the better!

At the moment Rails is focused on simplicity/readability. I've got a gem that I'm proposing (and DHH is evaluating) that adds caching as an option: https://github.com/rubys/dockerfile-rails#overview

even though the article does not go deep into multistage builds Fly.io does provide cookbooks and even a link to a Rails generator there.