Mounting a Rails engine in a Heroku app

Question

I have two projects that are version controlled in their own respective private GitHub repositories.

One of them is a Rails app, and the other one is a Rails engine.

I do not want to expose the Rails engine as a public gem.

How can I declare my Rails app has a dependency on the engine in such a way that Heroku can resolve it?

Answer 1

Assuming that your engine is a gem in a private Github repository, you can try this approach, which uses an OAuth token:

https://gist.github.com/masonforest/4048732

As noted in the comments, the version which involves hardcoding the OAuth token value in your Gemfile is less secure than using an environment variable.

Answer 2

You can use a private gem server like Gemfury. It is also a Heroku addon (free plan works fine for your case).

This way you'll be able to release versions of your gem. Works much like rubygems, but is private.

Answer 3

You can vendor your engine by placing the source in the vendor folder, then in your Gemfile reference it by path:

# Gemfile
gem 'some_engine', path: 'vendor/some_engine'

Either directly copy-paste the source there, or use a Git submodule. Run bundle install and you should be set.