hot-restarter.py 文件源码

def fork_and_exec():
  """ This routine forks and execs a new child process and keeps track of its PID. Before we fork,
      set the current restart epoch in an env variable that processes can read if they care. """

  global restart_epoch
  os.environ['RESTART_EPOCH'] = str(restart_epoch)
  print ("forking and execing new child process at epoch {}".format(restart_epoch))
  restart_epoch += 1

  child_pid = os.fork()
  if child_pid == 0:
    # Child process
    os.execl(sys.argv[1], sys.argv[1])
  else:
    # Parent process
    print ("forked new child process with PID={}".format(child_pid))
    pid_list.append(child_pid)