Using unicorn with heroku (cedar stack)

Posted: 2012-02-17

Updated: 2012-02-17

To use Unicorn instead of thin on heroku, do the following:

Add gem "unicorn" to your Gemfile
Add a Procfile
Add config/unicorn.rb

Procfile

1 web: bundle exec unicorn -p $PORT -c ./config/unicorn.rb
2 worker:  bundle exec rake jobs:work

Note: worker is not required, I just mentioned it because you might need it.

unicorn.rb

1 preload_app true
2 worker_processes 4 # amount of unicorn workers to spin up
3 timeout 30         # restarts workers that hang for 30 seconds
4 after_fork do |server, worker|
5   defined?(ActiveRecord::Base) and
6   ActiveRecord::Base.establish_connection
7 end

Note: the after_fork is required to avoid SSL errors with postgresql.