Using a gem for shared project code

gistfile1.txt

Sharing common code using a gem is a great idea, but it's painful to rapidly iterate in both codebases.

What we settled on something like:

if ENV['LOCAL_GEMS']
  gem 'shared_stuff', :path => '~/workspace/shared_stuff'
else
  gem 'shared_stuff, :github => 'mkocher/shared_stuff'
end

We'd check this in to the project, then we could set the environment variable and rebundle.  You'd have 
to do this when you decided that you wanted to change the shared code, and then once you're done you push 
the changes to the gem, then unset the env variable, then bundle to get the new hash in your gemfile lock.

Invariably someone will forget and check in the lock file pointing to the local copy. CI should catch this 
as long as the local path doesn't exist on CI.

Another issue we'd run into was someone would make breaking changes, but not bump everything that uses the 
gem.  Someone would modify project A, bump shared to match, and leave project B a ticking time bomb.  
Someone would come along later to work on B, decided they needed to modify shared, then bump it up and find 
things were horribly broken.  You want to be locked to a hash for deployment, but you could help this by 
having a second CI build that always pointed at HEAD of shared.

We hashed this out on a project about a year and a half ago.  You won't get to experience the pain of waiting 
2 minutes for bundler to resolve dependencies every time you bundle. (Thanks Bundler team!)

This was certainly better than copying the models, but I'd love to hear if someone has a better workflow.

Seems like a lot of fragility and pain for the one benefit.

At this point I'm considering an internal API between the main stack and the API service, with strategic caching on the API side...