code: def _daemonize(self):
          
          LOGGER.info('Forking %s into the background', sys.argv[0])
  
          # Write the pidfile if current uid != final uid
          if os.getuid() != self.uid:
              fd = open(self.pidfile_path, 'w')
              os.fchmod(fd.fileno(), 0o644)
              os.fchown(fd.fileno(), self.uid, self.gid)
              fd.close()
  
          try:
              pid = os.fork()
              if pid > 0:
                      sys.exit(0)
          except OSError as error:
                  raise OSError('Could not fork off parent: %s', error)
  
          # Set the user id
          if self.uid != os.getuid():
              os.setuid(self.uid)
  
          # Set the group id
          if self.gid != os.getgid():
              try:
                  os.setgid(self.gid)
              except OSError as error:
                  LOGGER.error('Could not set group: %s', error)
  
          # Decouple from parent environment
          os.chdir('/')
          os.setsid()
          os.umask(0o022)
  
          # Fork again
          try:
              pid = os.fork()
              if pid > 0:
                  sys.exit(0)
          except OSError as error:
              raise OSError('Could not fork child: %s', error)
  
          # redirect standard file descriptors
          sys.stdout.flush()
          sys.stderr.flush()
          si = open(os.devnull, 'r')
          so = open(os.devnull, 'a+')
          se = open(os.devnull, 'a+')
          os.dup2(si.fileno(), sys.stdin.fileno())
          os.dup2(so.fileno(), sys.stdout.fileno())
          os.dup2(se.fileno(), sys.stderr.fileno())
  
          # Automatically call self._remove_pidfile when the app exits
          atexit.register(self._remove_pidfile)
          self._write_pidfile()
docs: Fork into a background process and setup the process, copied in part
          from http://www.jejik.com/files/examples/daemon3x.py