Ruby application server
Ruby application web server
Ruby contains a default application web server named
WEBrick. As it is always present, most web framework use it by default. It’s good enough in
development, but it has never been thought to be a production server.
Do not use WEBrick
WEBrick has the following caracteristics:
- Single threaded
- Single process
It can’t handle several request in parallel, they are all in a single request queue. As a result, very pool performance can be expected. To get the best of your containers, you need to use a real production-ready application server.
Using Puma as a production server
To handle several requests in parallel, we recommend puma. To use it, just add it as dependency in your Gemfile:
and configure how to launch your app by defining a Procfile:
web: bundle exec puma -C config/puma.rb
The config file could like the following:
workers Integer(ENV['WEB_CONCURRENCY'] || 2) threads_count = Integer(ENV['MAX_THREADS'] || 5) threads threads_count, threads_count preload_app! rackup DefaultRackup port ENV['PORT'] || 3000 environment ENV['RACK_ENV'] || 'development' on_worker_boot do # Worker specific setup for Rails 4.1+ ActiveRecord::Base.establish_connection end
Thus you can easily change global settings by modifying the environment variables WEB_CONCURRENCY and MAX_THREAD and restarting your app.