Class: PoolParty::MonitorDaemon

Inherits:
Monitors::BaseMonitor show all
Defined in:
lib/poolparty/monitors/monitor_daemon.rb

Instance Attribute Summary collapse

Attributes inherited from Monitors::BaseMonitor

#last_cloud_loaded_time, #log_file_path

Class Method Summary collapse

Instance Method Summary collapse

Methods inherited from Monitors::BaseMonitor

#after_close_callbacks, #before_close_callbacks, #env, inherited, #log, #my_cloud

Constructor Details

#initialize(o = {}) ⇒ MonitorDaemon

Returns a new instance of MonitorDaemon.



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# File 'lib/poolparty/monitors/monitor_daemon.rb', line 14

def initialize(o={})
  @should_daemonize = o.delete(:daemonize)
  @pid_file = o.delete(:daemonize) || "/tmp/poolparty_monitor.pid"
  @sleep_time = o.delete(:sleep_time) || 20
        
  super
end

Instance Attribute Details

#pid_file ⇒ Object (readonly)

Returns the value of attribute pid_file.



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# File 'lib/poolparty/monitors/monitor_daemon.rb', line 8

def pid_file
  @pid_file
end

#should_daemonize ⇒ Object (readonly)

Returns the value of attribute should_daemonize.



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# File 'lib/poolparty/monitors/monitor_daemon.rb', line 8

def should_daemonize
  @should_daemonize
end

#sleep_time ⇒ Object (readonly)

Returns the value of attribute sleep_time.



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# File 'lib/poolparty/monitors/monitor_daemon.rb', line 8

def sleep_time
  @sleep_time
end

Class Method Details

.run(o = {}) ⇒ Object 



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# File 'lib/poolparty/monitors/monitor_daemon.rb', line 10

def self.run(o={})
  new(o).run
end

Instance Method Details

#daemonize(o = {}) ⇒ Object 



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# File 'lib/poolparty/monitors/monitor_daemon.rb', line 62

def daemonize(o={})
  raise unless pid_file
  
  pwd = Dir.pwd # Current directory is changed during daemonization, so store it
  
  remove_stale_pid_file
  pid = fork do
    Signal.trap('HUP') do
      restart
    end
    Signal.trap('INT') do
      stop!
    end
    Signal.trap("CHLD") do 
      Process.waitpid(pid, Process::WNOHANG)
    end
    File.open("/dev/null", "r+") do |devnull|
      $stdout.reopen(devnull)
      $stderr.reopen(devnull)
      $stdin.reopen(devnull) unless @use_stdin
    end
    run
  end
  
  Dir.chdir(pwd)
  
  write_pid_file(pid)

  Process.detach(pid)
end

#pass_the_baton ⇒ Object 



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# File 'lib/poolparty/monitors/monitor_daemon.rb', line 22

def pass_the_baton
  # Handle stats
  my_nominations = JSON.parse(open("http://localhost:8642/stats/get_nominations").read)
  unless my_nominations.empty?
    running_nodes = my_cloud.nodes(:status => "running")
    nominations = []
    running_nodes.each do |node|
      timeout(10) do
        log "Checking with #{node.internal_ip} for nominations: #{open("http://#{node.internal_ip}:8642/stats/get_nominations").read}"
        nominations << begin
          JSON.parse(open("http://#{node.internal_ip}:8642/stats/nominations").read) || "none"
        rescue
          log "Error when connecting to #{node.internal_ip}: #{e.inspect}"
          "none"
        end            
      end
    end
    log "Sending #{nominations.flatten.to_json} to #{server["/elections"].inspect}"
    # put to "http://localhost:8642/elections/handle_election", data => nominations.to_json
    server["/elections"].put(nominations.flatten.to_json)
  end
end

#pid ⇒ Object 



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# File 'lib/poolparty/monitors/monitor_daemon.rb', line 93

def pid
  @pid ||= File.file?(pid_file) ? open(pid_file).read.to_i : nil
end

#restart ⇒ Object 



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# File 'lib/poolparty/monitors/monitor_daemon.rb', line 105

def restart
  log "TODO: implement restart for HUP signal on #{__FILE__}"
end

#run ⇒ Object 



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# File 'lib/poolparty/monitors/monitor_daemon.rb', line 45

def run      
  if should_daemonize
    @should_daemonize = false
    daemonize
  else
    log "Starting MonitorDaemon"
    loop {          
      begin
        pass_the_baton
      rescue Exception => e
        log "There was an error with pass_the_baton: #{e}"
      end
      sleep sleep_time
    }
  end
end

#running? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/poolparty/monitors/monitor_daemon.rb', line 109

def running?
  return false unless pid
  Process.getpgid(pid) != -1
rescue Errno::ESRCH
  false
end

#send_signal(signal) ⇒ Object 



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# File 'lib/poolparty/monitors/monitor_daemon.rb', line 116

def send_signal(signal)
  if File.exist?(pid_file) && pid = open(pid_file).read
    pid = pid.to_i
    print "Sending #{signal} signal to process #{pid} ... "
    Process.kill(signal, pid)
    puts
    pid
  else
    puts "Can't stop process, no PID found in #{pid_file}"
    nil
  end
rescue Errno::ESRCH # No such process
  puts "process not found!"
  nil
end

#stop! ⇒ Object 



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# File 'lib/poolparty/monitors/monitor_daemon.rb', line 97

def stop!
  log "Stopping daemon"
  log_file.close
  send_signal("INT")
  remove_stale_pid_file
  exit 0
end