email_notifier.rb

module Depot
  class EmailNotifier < Bluepill::Trigger
    def initialize(process, options = {})
      @to_address = options.delete(:to_address)
      @from_address = options.delete(:from_address)
      @notify_on = options.delete(:notify_on)
      @rails_env = options.delete(:rails_env)
      super
    end

    def notify(transition)
      if @notify_on.include?(transition.to_name) && transited?(transition)
        IO.popen('/usr/sbin/sendmail -i -t', 'w') do |x|
          x.puts "From: #{@from_address}"
          x.puts "To: #{@to_address}"
          subject = "Bluepill(#{@rails_env}): #{process.name}, #{transition.from} => #{transition.to}"
          if transition.to_name == :unmonitored
            subject = "!URGENT! #{subject}"
          else
            subject = "[Notice] #{subject}"
          end
          x.puts "Subject: #{subject}"
          x.print "\n"
          x.puts "In #{@rails_env}, #{process.name} went from #{transition.from_name} => #{transition.to_name} at #{Time.now.strftime('%Y-%m-%d %H:%M:%S %Z')}"
        end
        @logger.info("notified via email")
      end
    rescue => ex
      @logger.warning("something wrong in email_notifier: #{ex.message}")
      @logger.warning(ex.backtrace)
    end

    def transited?(trans)
      trans.to_name != trans.from_name
    end
  end
end

process.checks(:email_notifier,
  :rails_env => 'production',
  :from_address => 'you@example.com',
  :to_address => 'me@example.com',
  :notify_on => [:up, :down, :starting, :unmonitored])