Python 子进程 Popen.terminate() 仍然停留在 wait()

Question

我正在尝试使用 RPi 实现无线电播放器。目标是设置播放列表并在填充播放列表后开始播放。一旦停止代码被执行，播放器和广播进程应该退出。

广播进程很好地终止，但播放器进程即使在调用终止后仍处于等待状态。如果再次调用停止代码，则播放器进程终止

尝试过的事情：

1. 重新排序等待命令（播放器、收音机）/（收音机、播放器）
2. 类似地重新排序终止命令
3. 使用 kill 而不是 terminate 会挂起 RPi

玩家代码：

while playlist:
    player = subprocess.Popen(
            ["avconv", "-i", "Music/%s" % playlist[0], "-f", "s16le", "-ar", 
            "22.05k", "-ac", "1", "-"], stdout=subprocess.PIPE)

    radio = subprocess.Popen(["./pifm", "-", freq], stdin=player.stdout)

    radio.wait()
    print "************ exiting from radio :)"
    player.wait()
    print "************ exiting from player :)"

    playlist.pop(0)
player = None
radio = None

播放器停止代码（从另一个线程调用）：

print "************ stop requested"

if radio and radio.poll() is None:
    print "************ terminating radio :)"
    radio.terminate()

if player and player.poll() is None:
    print "************ terminating player :)"
    player.terminate()

替代方案：

另一种选择是为广播设置一个持久接收器，并为播放器设置点播流程

def start_radio():
    global radio
    radio = subprocess.Popen(["./pifm"...], stdin=subprocess.PIPE)

def play():
    global player
    while playlist and radio:
        player = subprocess.Popen(["avconv"...], stdout=radio.stdin)
        player.wait()
        playlist.pop(0)

def stop():
   if player and player.poll() is None:
      print "************ terminating player :)"
      player.terminate()

但在这种情况下，调用 player.terminate() 会关闭播放器，同时在无线电进程上重复播放最后一个数据包（就像一个卡住的记录）。这张卡住的唱片一直播放到我启动新播放器或终止收音机为止。

Answer 1

正如@J.F.Sebastian 提到的，使用player.stdout.close() 有效。整个代码库在这里发布https://github.com/hex007/pifm_server

所以最终的代码看起来像这样

while playlist:
    player = subprocess.Popen(
            ["avconv", "-i", "Music/%s" % playlist[0], "-f", "s16le", "-ar", 
            "22.05k", "-ac", "1", "-"], stdout=subprocess.PIPE)

    radio = subprocess.Popen(["./pifm", "-", freq], stdin=player.stdout)

    player.stdout.close()

    radio.wait()
    player.wait()

    if stop_requested:
        stop_requested = False
        break

    playlist.pop(0)

player = None
radio = None

以及停止代码：

stop_requested = True

if radio and radio.poll() is None:
    radio.terminate()

if player and player.poll() is None:
    player.terminate()