subprocess的管道输出 . 打开文件

3 回答

• 2

  我同时运行两个子进程，并将两者的输出保存到单个日志文件中 . 我还 Build 了一个超时来处理挂起的子进程 . 当输出太大时，超时总是触发，并且任何一个子进程的stdout都不会保存到日志文件中 . 亚历克斯上面提出的答案并没有解决它 .

  # Currently open log file.
  log = None
  
  # If we send stdout to subprocess.PIPE, the tests with lots of output fill up the pipe and
  # make the script hang. So, write the subprocess's stdout directly to the log file.
  def run(cmd, logfile):
     #print os.getcwd()
     #print ("Running test: %s" % cmd)
     global log
     p = subprocess.Popen(cmd, shell=True, universal_newlines = True, stderr=subprocess.STDOUT, stdout=logfile)
     log = logfile
     return p
  
  
  # To make a subprocess capable of timing out
  class Alarm(Exception):
     pass
  
  def alarm_handler(signum, frame):
     log.flush()
     raise Alarm
  
  
  ####
  ## This function runs a given command with the given flags, and records the
  ## results in a log file. 
  ####
  def runTest(cmd_path, flags, name):
  
    log = open(name, 'w')
  
    print >> log, "header"
    log.flush()
  
    cmd1_ret = run(cmd_path + "command1 " + flags, log)
    log.flush()
    cmd2_ret = run(cmd_path + "command2", log)
    #log.flush()
    sys.stdout.flush()
  
    start_timer = time.time()  # time how long this took to finish
  
    signal.signal(signal.SIGALRM, alarm_handler)
    signal.alarm(5)  #seconds
  
    try:
      cmd1_ret.communicate()
  
    except Alarm:
      print "myScript.py: Oops, taking too long!"
      kill_string = ("kill -9 %d" % cmd1_ret.pid)
      os.system(kill_string)
      kill_string = ("kill -9 %d" % cmd2_ret.pid)
      os.system(kill_string)
      #sys.exit()
  
    end_timer = time.time()
    print >> log, "closing message"
  
    log.close()
  

  回复于 2024-04-24T07:27:11+08:00
• 63

  您可以将 stdout 和 stderr 作为参数传递给 Popen()

  subprocess.Popen(self, args, bufsize=0, executable=None, stdin=None, stdout=None,
                   stderr=None, preexec_fn=None, close_fds=False, shell=False,
                   cwd=None, env=None, universal_newlines=False, startupinfo=None, 
                   creationflags=0)
  

  例如

  >>> import subprocess
  >>> with open("stdout.txt","wb") as out, open("stderr.txt","wb") as err:
  ...    subprocess.Popen("ls",stdout=out,stderr=err)
  ... 
  <subprocess.Popen object at 0xa3519ec>
  >>>
  

  回复于 2024-04-24T07:27:11+08:00
• 35

  按the docs，

  stdin，stdout和stderr分别指定执行程序的标准输入，标准输出和标准错误文件句柄 . 有效值为PIPE，现有文件描述符（正整数），现有文件对象和无 .

  所以只需将open-for-writing文件对象作为命名参数 stdout= 和 stderr= 传递，你应该没问题！

  回复于 2024-04-24T07:27:11+08:00