How can Bundler/Gemfile be configured to use different gem sources during development?

Question

I have a Sinatra application that requires another gem I'm developing locally. I'm having trouble configuring Bundler to use my local gem code during development but my vendored gem code in production.

Ideally I could do something like this, but Bundler doesn't allow you to specify the same gem twice:

# Doesn't work:
group :development do
  gem 'awesome', :path => "~/code/awesome"
end

group :production do
  gem 'awesome', :path => "vendor/gems/awesome-0.0.1"
end

In the meantime I've resorted to manually vendoring the gem & updating the gem source in the Gemfile every single time I deploy, which is quite a hassle. My workflow is this:

1. Point to my local gem during development (gem 'awesome', :path => "~/code/awesome")
2. When ready to deploy, unpack gem into vendor/gems
3. Update Gemfile to point to vendored gem (gem 'awesome', :path => "vendor/gems/awesome-0.0.1")
4. Run bundle install (to update Gemfile.lock)
5. Deploy code
6. Return to step 1.

What a hassle! I'd like to do something cleaner than simply writing Rake tasks to automate my current setup.

What's the best workflow for this scenario?

Answer 1

There is a new feature that allows to do that, by simply specyfing local.gem_name config option, like:

bundle config local.rack ~/path/to/local/rack

This only works if the gem has a git repo and branch specified in the Gemfile.

See thr Bundler docs for more details: http://bundler.io/v1.3/bundle_config.html

Answer 2

Apparently, you can use regular Ruby in your Gemfile. According to this article you can set an environment variable (or any other variable, I've found), to let you pick which version of a gem you want to use.

## based on an ENV variable
if ENV['RACK_ENV'] == "development"
  gem 'awesome', :path => "~/code/awesome"
else
  gem 'awesome', :path => "vendor/gems/awesome-0.0.1"
end

Maybe that'll work. If you need to vendor your in-progress gem maybe you could make a tiny little script that'll set the ENV, vendor it, and reset the ENV. Eh?

Answer 3

Here is a suggestion which I didn't get to fully work (used for a spree theme and I got problems with some stylesheets from the theme):

group :production do
      gem 'gemname', '~> 0.1.6', :git => 'git://github.com/foouser/gemname.git'
end

group :development do
      gem 'gemnamedev', :path => '~/path/gemname' # use local version
end

Duplicate your gemname.gemspec file and call it gemnamedev.gemspec, and change s.name inside it to "gemnamedev".