子进程 popen stdout 锁定？

您好，在使用 subprocess.Popen 时，读取标准输出时遇到一些问题

daniel@desktop:~$ python -V
Python 2.7.3

这是代码：（注释代码是我尝试过的一些事情）

import subprocess

RUN = './hlds_run -game cstrike -maxplayers 11'

p = subprocess.Popen(RUN.split(), shell=False, stdout=subprocess.PIPE, stdin=subprocess.PIPE, stderr=subprocess.PIPE)

while 1:
    try:
        out = p.stdout.readline()
        #if out == '':
        #   out = p.stdout.read()
        #p.stdout.flush()
    except: 
        p.terminate()
        break

    try:
        err = p.stderr.readline()
        #if err == '':
        #   err = p.stderr.read()
        #p.stderr.flush()
    except:
        p.terminate()
        break
    if out != '':
        print out.rstrip()

    if err != '':
        print err.rstrip()


    #print '\n' #constantly prints new lines until "Calling BreakpadMiniDumpSystemInit."

这是连接到服务器并断开连接时得到的输出：

daniel@desktop:~/hlds$ python hlds.py 
Auto detecting CPU
Using breakpad crash handler
Using Pentium II Optimised binary.
Setting breakpad minidump AppID = 10
Auto-restarting the server on crash
Forcing breakpad minidump interfaces to load

Looking up breakpad interfaces from steamclient
Console initialized.
Calling BreakpadMiniDumpSystemInit
scandir failed:/home/daniel/hlds/./valve/SAVE
Installing breakpad exception handler for appid(10)/version(5447)
scandir failed:/home/daniel/hlds/./platform/SAVE
Looking up breakpad interfaces from steamclient
Protocol version 48
Calling BreakpadMiniDumpSystemInit

while 循环在以下情况后锁定：

Calling BreakpadMiniDumpSystemInit.

但服务器仍在运行，我可以连接、运行命令等...

如果我跑：

 ./hlds_run -game cstrike -maxplayers 11 >> stdout.log 2>&1

我在 stdout.log 中得到以下输出：

daniel@desktop:~/hlds$ cat stdout.log 
Auto detecting CPU
Using Pentium II Optimised binary.
Auto-restarting the server on crash

Console initialized.
Using breakpad crash handler
Setting breakpad minidump AppID = 10
Forcing breakpad minidump interfaces to load
Looking up breakpad interfaces from steamclient
Calling BreakpadMiniDumpSystemInit
Installing breakpad exception handler for appid(10)/version(5447)
scandir failed:/home/daniel/hlds/./valve/SAVE
scandir failed:/home/daniel/hlds/./platform/SAVE
Protocol version 48
Exe version 1.1.2.6/Stdio (cstrike)
Exe build: 14:06:24 Sep 23 2011 (5447)
STEAM Auth Server
Server IP address 127.0.1.1:27015
couldn't exec listip.cfg
couldn't exec banned.cfg
Looking up breakpad interfaces from steamclient
Calling BreakpadMiniDumpSystemInit
scandir failed:/home/daniel/hlds/./valve/SAVE
scandir failed:/home/daniel/hlds/./platform/SAVE

Could not establish connection to Steam servers.
Reconnected to Steam servers.
   VAC secure mode is activated.
ERROR: couldn't open custom.hpk.
JAMES HETFIELD : hello!
Dropped JAMES HETFIELD from server
Reason:  Client sent 'drop'
Sat Apr 14 00:10:54 CEST 2012: Server Quit

但是，如果我不执行 2>&1，我仍然会在 stdout 中得到此输出，并在 stdout.log 中得到其余输出：

daniel@desktop:~/hlds$ ./hlds_run -game cstrike -maxplayers 11 >> stdout.log
Using breakpad crash handler
Setting breakpad minidump AppID = 10
Forcing breakpad minidump interfaces to load
Looking up breakpad interfaces from steamclient
Calling BreakpadMiniDumpSystemInit
Installing breakpad exception handler for appid(10)/version(5447)
Looking up breakpad interfaces from steamclient
Calling BreakpadMiniDumpSystemInit

尝试创建服务器管理器和调度程序作为子流程学习经验:]

感谢所有帮助！ :)

发生的情况是，其中一个管道被数据填满，从而阻塞子进程，而您的 python 进程在尝试从另一个管道读取一行时被阻塞，从而导致死锁。您可能想使用某种轮询（select/poll/epoll），而不是在管道上进行阻塞读取。

一个快速的破解方法是在 while 循环中进行非阻塞读取，但这会导致 python 进程使用大量 CPU。

看一下文档select http://docs.python.org/library/select.html模块以获取有关以非 hacky 方式解决问题的更多信息。