Module: Smith::AgentProcessObserver

Includes:
Logger
Defined in:
lib/smith/agent_process.rb

Class Method Summary collapse

Methods included from Logger

included

Class Method Details

.acknowledge_start(agent_process, &blk) ⇒ Object 



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# File 'lib/smith/agent_process.rb', line 202

def self.acknowledge_start(agent_process, &blk)
  logger.info { "Agent started: #{agent_process.uuid}" }
end

.acknowledge_stop(agent_process) ⇒ Object 



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# File 'lib/smith/agent_process.rb', line 224

def self.acknowledge_stop(agent_process)
  agent_process.delete
  logger.info { "Agent stopped: #{agent_process.uuid}" }
end

.kill(agent_process) ⇒ Object

This needs to use the PID class to verify if an agent is still running. FIXME



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# File 'lib/smith/agent_process.rb', line 231

def self.kill(agent_process)
  if agent_process.pid
    if agent_process.pid == 0
      logger.info { "Agent's pid is 0. The agent probably didn't start correctly. Cleaning up." }
      agent_process.delete
    else
      logger.info { "Sending kill signal: #{agent_process.pid}: #{agent_process.uuid}" }
      begin
        Process.kill('TERM', agent_process.pid)
      rescue
        logger.error { "Process does not exist. PID is stale: #{agent_process.pid}: #{agent_process.uuid}" }
      end
    end
  else
    logger.error { "Not sending kill signal, agent pid is not set: #{agent_process.uuid}" }
  end
  agent_process.delete
end

.no_process_running(agent_process) ⇒ Object 



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# File 'lib/smith/agent_process.rb', line 219

def self.no_process_running(agent_process)
  agent_process.delete
end

.reap_agent(agent_process) ⇒ Object

If an agent is in an unknown state then this will check to see if the process is still alive and if it is kill it, otherwise log a message. TODO this is not really a reaper but I haven’t quite worked out what I’m going to do with it so I’ll leave it as is



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# File 'lib/smith/agent_process.rb', line 255

def self.reap_agent(agent_process)
  logger.info { "Reaping agent: #{agent_process.uuid}" }
  if Pathname.new('/proc').join(agent_process.pid.to_s).exist?
    logger.warn { "Agent is still alive: #{agent_process.uuid}" }
  else
    logger.warn { "Agent is already dead: #{agent_process.uuid}" }
  end
end

.start(agent_process) ⇒ Object 



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# File 'lib/smith/agent_process.rb', line 162

def self.start(agent_process)
  if agent_process.exists?
    agent_process.check
  else
    agent_process.delete
  end
end

.start_process(agent_process) ⇒ Object

Start an agent. This forks and execs the bootstrapper class which then becomes responsible for managing the agent process.



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# File 'lib/smith/agent_process.rb', line 172

def self.start_process(agent_process)
  fork do
    # Detach from the controlling terminal
    unless Process.setsid
      raise 'Cannot detach from controlling terminal'
    end

    # Close all file descriptors apart from stdin, stdout, stderr
    ObjectSpace.each_object(IO) do |io|
      unless [STDIN, STDOUT, STDERR].include?(io)
        io.close unless io.closed?
      end
    end

    # Sort out the remaining file descriptors. Don't do anything with
    # stdout (and by extension stderr) as want the agency to manage it.
    STDIN.reopen("/dev/null")
    STDERR.reopen(STDOUT)

    bootstrapper = Pathname.new(__FILE__).dirname.join('bootstrap.rb').expand_path

    binary = Smith.config.ruby[agent_process.name]
    logger.debug { "Launching #{agent_process.name} with: #{binary}" }
    exec(binary, bootstrapper.to_s, agent_process.name, agent_process.uuid)
  end

  # We don't want any zombies.
  Process.detach(agent_process.pid)
end

.stop(agent_process) ⇒ Object 



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# File 'lib/smith/agent_process.rb', line 206

def self.stop(agent_process)
  Messaging::Sender.new(agent_process.control_queue_def) do |sender|
    sender.consumer_count do |count|
      if count > 0
        sender.publish(ACL::AgentCommand.new(:command => 'stop'))
      else
        logger.warn { "Agent is not listening. Setting state to dead." }
        agent_process.no_process_running
      end
    end
  end
end