App platform: "Dockerfile detected" on a rails app

Posted October 24, 2020
DigitalOcean App Platform

I’m excited to try out the new App platform. I’ve been asking Santa for something like this from DO for years.

I’ve got a rails app that happens to have a Dockerfile in the repo. I would expect this to be deployed with the rails bootpack, but when I try to setup the app, it says “Dockerfile detected” and tries to deploy it as a docker app. How do I deploy it as a rails app/buildpack?

Wilson29thID

Submit an answer

You can type!ref in this text area to quickly search our full set of tutorials, documentation & marketplace offerings and insert the link!

These answers are provided by our Community. If you find them useful, show some love by clicking the heart. If you run into issues leave a comment, or add your own answer to help others.

Steven Normore • October 24, 2020

Accepted Answer

@Wilson29thID 👋

Thanks for trying out the App Platform! You’re right that currently if you create an app through the UI, and your repo contains a Dockerfile at the root, then we’ll automatically use that instead of the Ruby/Rails buildpack.

You have a couple options:

Rename your Dockerfile to something else so it’s not auto-detected (admittedly not ideal), or
Use doctl directly with a custom app spec that doesn’t include a dockerfile_path (which is what the UI is injecting).

If you go with option (2), your custom app spec might look something like this initially:

name: sample-rails
services:
- name: web
  github:
    repo: digitalocean/sample-rails
    branch: main
    deploy_on_push: true
  environment_slug: ruby-on-rails