fredjean/simpler_workflow

module SimplerWorkflow

    module ParentProcess

        # This class is aimed to be used with daemons gem or something similar
        # it launches as many workers as required, which is just running the on boot time block n times
        # a sample daemon using daemons gem would like this:

        #    #!/usr/bin/env/ ruby
        #    require 'rubygems'
        #    require 'bundler/setup'
        #    require 'daemons'
        #    dirmode = :normal
        #    # Check if we're in a deployment machine
        #    # to store logs in /var/run or in the app folder
        #    if ENV['ENV']
        #        log_dir = "/var/log/swf"
        #        pid_dir = "/var/run/swf"
        #    else
        #        log_dir = File.expand_path '../log/', __FILE__
        #        pid_dir = File.expand_path '../log/pid', __FILE__
        #    end
        #    script_path = File.expand_path '../boot.rb', __FILE__
        #    Daemons.run script_path, {
        #        :app_name   => "my_daemon",
        #        :dir_mode   => dirmode,
        #        :log_dir    => log_dir,
        #        :dir        => pid_dir,
        #        :multiple   => false,
        #        :monitor    => true,
        #        :log_output => true,
        #        # backtrace causes errors detecting as uncatched
        #        # some correctly handled exceptions. Keep disabled.
        #        :backtrace  => false
        #      }


        require 'fileutils'

        def self.extended(base)

            $logger = Logger.new STDOUT
            
            base.extend ClassMethods

            Signal.trap('TERM') { base.graceful_exit 'QUIT'}

            Signal.trap('INT') { base.graceful_exit 'INT'}
            
        end

        module ClassMethods

            def graceful_exit(s)
                SimplerWorkflow.child_processes.each do |child| 
                    Process.kill(s, child)
                end
            end
            
            def workers(val)
                @workers = val
            end

            def log_level(val)
                @log_level = val
            end

            def on_boot(&block)
                    $logger.level = @log_level if @log_level
                    # separate this execution in the log
                    $logger.info "Booting with #{@workers} workers----------------------------"
                    @workers.times { yield }
                    # we wait for all children processes to exit; when QUIT is sent
                    # we terminate them and this will automatically exit.
                    Process.waitall
                
            end

        end
    end
end