via rubygems

gem install leafy-health

or add to your Gemfile

gem 'leqfy-health'

installing the gem also takes care of the jar dependencies with jruby-1.7.16+

an instance of the registry Leafy::Health::Registry can register and unresgister health-checks under a given name. any object with a #call method will do or block on the register method.

 registry = Leafy::Health::Registry.new

you can ask the registry which names have already health-checks registered:

 registry.names

simple in the sense that either call returns nil which means healthy or a message which is the unhealthy state. the message can be any String.

registry.register( 'simple.block') do
  if app.crashed
    'application crashed'
  end
end

or with a health-check object

class AppCheck
  def call
    if app.crashed
      'application crashed'
    end
  enf
end
registry.register( 'simple.class', AppCheck.new )

here the call method gets an argument which allows to create both healthy and unhealthy states with message.

registry.register( 'app.block') do |health|
  if app.crashed
    health.unhealthy( 'application crashed' )
  else
    health.healthy( 'application ok' )
  end
end

or with a health-check object

class AppCheck
  def call( health )
    if app.crashed
      health.unhealthy( 'application crashed' )
    else
      health.healthy( 'application ok' )
    end
  end
end
registry.register( 'app.class', AppCheck.new )

registry.unregister( 'app.class' )

currently there is not further introspection on the registry and its health-check. with the Leafy::Json::HealthWriter (from leafy-rack) you can get a json representation of the current health report

Leafy::Json::HealthWriter.to_json( registry.health )

get all the gems and jars in place

gem install jar-dependencies --development
bundle install

for running all specs

rake

or

rspec spec/reporter_spec.rb