Inspired by the ease of installing and setting up fitter-happier as a Rails application's health check, but frustrated by its lack of flexibility, OK Computer was born. It provides a robust endpoint to perform server health checks with a set of built-in plugins, as well as a simple interface to add your own custom checks.

Add this line to your application's Gemfile:

gem 'okcomputer'

And then execute:

$ bundle

Or install it yourself as:

$ gem install okcomputer

To perform the default checks (application running and ActiveRecord database connection), do nothing other than adding to your application's Gemfile.

We also include a MongoidCheck, but do not register it. If you use Mongoid, replace the default ActiveRecord check like so:

OKComputer::Registry.register "database", OKComputer::MongoidCheck.new

If you use another database adapter, see Registering Custom Checks below to build your own database check and register it with the name "database" to replace the built-in check, or use OKComputer::Registry.deregister "database" to stop checking your database altogether.

Register additional checks in an initializer, like do:

# config/initializers/okcomputer.rb
OKComputer::Registry.register "resque_down", OKComputer::ResqueDownCheck.new("critical", 100)
OKComputer::Registry.register "resque_backed_up", OKComputer::ResqueBackedUpCheck.new

The simplest way to register a check unique to your application is to subclass OKComputer::Check and implement your own #call method, which returns the output string, and calls mark_failure if anything is wrong.

# config/initializers/okcomputer.rb
class MyCustomCheck < OKComputer::Check
  def call
    if rand(10).even?
      "Even is great!"
    else
      mark_failure
      "We don't like odd numbers"
    end
  end
end

OKComputer::Registry.register "check_for_odds", MyCustomCheck.new

• Perform a simple up check: https://example.com/okcomputer
• Perform all installed checks: https://example.com/okcomputer/all
• Perform a specific installed check: https://example.com/okcomputer/database

Checks are available as plain text (by default) or JSON by appending .json, e.g.:

• https://example.com/okcomputer.json
• https://example.com/okcomputer/all.json

1. Fork it
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Add some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create new Pull Request