health_check.rb

class HealthCheck
  class << self
    def check!
      status = {
        service: service_working?,
        db: db_connected?
      }
      [status.values.all?, status]
    rescue e
      [false, :exception => e.message]
    end
  end
end

get '/health_check' do
  healthy, details = HealthCheck.check!
  [
    healthy ? 200 : 500,
    {"Content-Type": "application/json"},
    details.to_json
  ]
end