Class: Bullring::DrubiedProcess

Inherits:
Object
  • Object
show all
Defined in:
lib/bullring/util/drubied_process.rb

Instance Method Summary collapse

Constructor Details

#initialize(options, &block) ⇒ DrubiedProcess

options looks like:

{

:process => {
  :host => [the hostname / IP address that the process listens on],
  :port => [the port that the process listens on],
  :command => [the command to run the process],
  :args => [the arguments to the process command]
}

}

The provided block will be called whenever this process connects (or reconnects) to a process, including when the process is restarted. This makes the block a good place to put initialization code for the process.



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# File 'lib/bullring/util/drubied_process.rb', line 26

def initialize(options, &block)
  @options = options
  @after_connect_block = block
  connect_to_process!
end

Dynamic Method Handling

This class handles dynamic methods through the method_missing method

#method_missing(m, *args, &block) ⇒ Object 



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# File 'lib/bullring/util/drubied_process.rb', line 52

def method_missing(m, *args, &block)  
  restart_if_needed!

  @process.logger = Bullring.logger
  result = @process.send(m, *args, &block)
  @process.logger = nil

  result
end

Instance Method Details

#alive? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/bullring/util/drubied_process.rb', line 32

def alive?
  begin
    (@process.nil? || @process.alive?).tap{|is_alive| Bullring.logger.debug {"#{caller_name} #{is_alive ? 'is alive!' : 'is not alive!'}"}}
  rescue DRb::DRbConnError => e
    Bullring.logger.debug {"#{caller_name}: Checking if server alive and got a connection error: " + e.inspect}
    return false
  rescue StandardError => e # things like name errors, in case server doesn't have an alive? method
    Bullring.logger.debug {"#{caller_name}: Checking if server alive and got an error: " + e.inspect}
    true
  rescue
    Bullring.logger.debug {"#{caller_name}: Checking if server alive and got an unknown error"}
    true
  end
end

#connect_to_process! ⇒ Object

Creates a druby connection to the process, starting it up if necessary



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# File 'lib/bullring/util/drubied_process.rb', line 69

def connect_to_process!
  Bullring.logger.debug{"#{caller_name}: Connecting to process..."}

  if !process_port_active?
    Bullring.logger.debug {"#{caller_name}: Spawning process..."}

    # Spawn the process in its own process group so it stays alive even if this process dies
    pid = Process.spawn([@options[:process][:command], @options[:process][:args]].flatten.join(" "), {:pgroup => true})
    Process.detach(pid)

    time_sleeping = 0
    while (!process_port_active?)
      sleep(0.2)
      if (time_sleeping += 0.2) > @options[:process][:max_bringup_time]
        Bullring.logger.error {"#{caller_name}: Timed out waiting to bring up the process"}
        raise StandardError, "#{caller_name}: Timed out waiting to bring up the process", caller
      end
    end
  end

  if !@local_service.nil?
    @local_service.stop_service
    Bullring.logger.debug {"#{caller_name}: Stopped local service on #{@local_service.uri}"}
  end
  
  @local_service = DRb.start_service "druby://127.0.0.1:0"
  Bullring.logger.debug {"#{caller_name}: Started local service on #{@local_service.uri}"}

  @process = DRbObject.new nil, "druby://#{host}:#{port}"
  
  @after_connect_block.call(@process) if !@after_connect_block.nil?
end

#process_port_active? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/bullring/util/drubied_process.rb', line 62

def process_port_active?
  in_use = Network::is_port_in_use?(host,port)
  Bullring.logger.debug {"#{caller_name}: Port #{port} on #{host} is #{in_use ? 'active' : 'inactive'}."}
  in_use
end

#restart_if_needed! ⇒ Object 



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# File 'lib/bullring/util/drubied_process.rb', line 47

def restart_if_needed!
  Bullring.logger.debug {"#{caller_name}: In restart_if_needed!"}
  alive? || connect_to_process!
end