Module: Cognizant::Process::PID

Included in:
Cognizant::Process
Defined in:
lib/cognizant/process/pid.rb

Instance Method Summary collapse

Instance Method Details

#cached_pid ⇒ Object 



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# File 'lib/cognizant/process/pid.rb', line 4

def cached_pid
  if not @process_pid or @process_pid == 0
    read_pid
  else
    @process_pid
  end
end

#read_pid ⇒ Object 



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# File 'lib/cognizant/process/pid.rb', line 12

def read_pid
  if self.pid_command
    str = execute(self.pid_command).stdout.to_i
    process_pid = str unless not str or str.zero?
    # TODO: Write pid to pidfile, since our source was pid_command instead.
  elsif self.pidfile and File.exists?(self.pidfile)
    str = File.read(self.pidfile).to_i
    process_pid = str unless not str or str.zero?
  end
  process_pid = 0 unless Cognizant::System.pid_running?(process_pid) # If the newly fetched pid is not running, reset it.
  @process_pid = process_pid
end

#unlink_pid ⇒ Object

Note: Expected that this method is not called to unlink pidfile if the process daemonizes itself (and hence manages the pidfile by itself).



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# File 'lib/cognizant/process/pid.rb', line 32

def unlink_pid
  File.unlink(self.pidfile) if self.pidfile
rescue Errno::ENOENT
  # It got deleted before we could. Perhaps it was a process managed pidfile.
  true
end

#write_pid(pid = nil) ⇒ Object

Note: Expected that this method is not called to overwrite pidfile if the process daemonizes itself (and hence manages the pidfile by itself).



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# File 'lib/cognizant/process/pid.rb', line 26

def write_pid(pid = nil)
  @process_pid = pid
  File.open(self.pidfile, "w") { |f| f.write(@process_pid) } if self.pidfile and @process_pid and @process_pid != 0
end