RevisionPlate

Rack application and middleware that serves endpoint returns application's REVISION.

The endpoint returns content of REVISION

Content of the endpoint wouldn't be changed even if REVISION file has changed. But it'll return 404 when it has removed.

This can be used for health check + remove from service by hand.

This gem is used in Cookpad. And seems several companies runs similar thing (e.g. GitHub).

# Gemfile
gem 'revision_plate', require: 'revision_plate/rails'

then your Rails application will handle /site/sha.

# Gemfile
gem 'revision_plate'

# config.ru (middleware)
use RevisionPlate::Middleware, '/site/sha', "#{__dir__}/REVISION"

# config.ru (mount)
map '/site/sha' do
  run RevisionPlate::App.new("#{__dir__}/REVISION")
end

$ echo 'deadbeef' > REVISION
$ (... start your app ...)
$ curl localhost:3000/site/sha
deadbeef
$ rm REVISION
$ curl localhost:3000/site/sha
REVISION_FILE_REMOVED

remove require: 'revision_plate/rails' from Gemfile, then initialize RevisionPlate::App on routes:

# routes.rb
get '/site/sha' => RevisionPlate::App.new
get '/site/sha' => RevisionPlate::App.new("/path/to/my/favorite/REVISION")

$ rake test

MIT License