Class: ScoutAgent::Lifeline

Inherits:
Object
  • Object
show all
Includes:
Tracked
Defined in:
lib/scout_agent/lifeline.rb

Constant Summary collapse

NO_CONTACT_TIMEOUT = 
3
CHECK_IN_FREQUENCY =

gives us three check ins before a cutoff

0.99
TERM_TO_KILL_PAUSE = 
1
RELAUNCH_FREQUENCIES = 
[0, 1, 1, 2, 3, 5, 8, 13]

Instance Attribute Summary collapse

Instance Method Summary collapse

Methods included from Tracked

#clear_status, #force_status_database_reload, #status_database, #status_log

Constructor Details

#initialize(agent, log = WireTap.new(nil)) ⇒ Lifeline

Interface ###



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# File 'lib/scout_agent/lifeline.rb', line 15

def initialize(agent, log = WireTap.new(nil))
  @agent                       = agent
  @log                         = log
  @parent_pid                  = Process.pid
  @child_pid                   = nil
  @reader                      = nil
  @writer                      = nil
  @launch_and_monitor_thread   = nil
  @check_in_with_parent_thread = nil
  @code                        = nil
  @last_launch                 = nil
  @relaunch_index              = 0
  
  at_my_exit do
    clear_status
  end
end

Instance Attribute Details

#log ⇒ Object (readonly)

Returns the value of attribute log.



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# File 'lib/scout_agent/lifeline.rb', line 35

def log
  @log
end

Instance Method Details

#join ⇒ Object 



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# File 'lib/scout_agent/lifeline.rb', line 64

def join
  if Process.pid == @parent_pid and @launch_and_monitor_thread
    @launch_and_monitor_thread.join
  end
end

#launch_and_monitor ⇒ Object 



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# File 'lib/scout_agent/lifeline.rb', line 37

def launch_and_monitor
  @launch_and_monitor_thread = Thread.new do
    Thread.current.abort_on_exception = true
    loop do
      wait_for_launch
      prepare_pipe
      launch_child
      close_writer
      monitor_child
      restart_child
    end
  end
end

#terminate ⇒ Object 



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# File 'lib/scout_agent/lifeline.rb', line 51

def terminate
  if Process.pid == @parent_pid
    # stop monitoring
    log.info("Stopping the monitoring for '#{@agent}'.")
    @launch_and_monitor_thread.exit if @launch_and_monitor_thread
    # ask child process to exit
    log.info("Asking '#{@agent}' to stop.")
    IDCard.new(@agent).signal("TERM")
  end
rescue Errno::ESRCH  # no such process
  # if already exited, so we are fine
end