运行子流程并将输出打印到日志

Question

我正在寻找从python调用shell脚本并使用日志记录将其stdout和stderr写入文件的方法。这是我的代码：

import logging
import tempfile
import shlex
import os

def run_shell_command(command_line):
    command_line_args = shlex.split(command_line)

    logging.info('Subprocess: \"' + command_line + '\"')

    process_succeeded = True
    try:
        process_output_filename = tempfile.mktemp(suffix = 'subprocess_tmp_file_')
        process_output = open(process_output_filename, 'w')

        command_line_process = subprocess.Popen(command_line_args,\
                                                stdout = process_output,\
                                                stderr = process_output)
        command_line_process.wait()
        process_output.close()

        process_output = open(process_output_filename, 'r')
        log_subprocess_output(process_output)
        process_output.close()

        os.remove(process_output_filename)
    except:
        exception = sys.exc_info()[1]
        logging.info('Exception occured: ' + str(exception))
        process_succeeded = False

    if process_succeeded:
        logging.info('Subprocess finished')
    else:
        logging.info('Subprocess failed')

    return process_succeeded

而且我敢肯定，有一种方法可以做到，而无需创建临时文件来存储进程输出。有任何想法吗？

Answer 1

我敢肯定有一种方法可以做到，而无需创建临时文件来存储进程输出

您只需要检查的文档Popen，尤其是有关stdout和的文档stderr：

stdin，stdout并分别stderr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None。PIPE指示应创建到子级的新管道。使用默认设置时
None，将不会发生重定向。子级的文件句柄将从父级继承。另外，stderr可以是STDOUT，表示stderr来自子进程的数据应捕获到与相同的文件句柄中stdout。

因此，您可以看到可以使用文件对象或PIPE值。这使您可以使用该communicate()方法来检索输出：

from StringIO import StringIO
process = subprocess.Popen(arguments, stdout=subprocess.PIPE, stderr=subprocess.STDOUT)
output, error = process.communicate()
log_subprocess_output(StringIO(output))

我会将您的代码重写为：

import shlex
import logging
import subprocess
from StringIO import StringIO

def run_shell_command(command_line):
    command_line_args = shlex.split(command_line)

    logging.info('Subprocess: "' + command_line + '"')

    try:
        command_line_process = subprocess.Popen(
            command_line_args,
            stdout=subprocess.PIPE,
            stderr=subprocess.STDOUT,
        )

        process_output, _ =  command_line_process.communicate()

        # process_output is now a string, not a file,
        # you may want to do:
        # process_output = StringIO(process_output)
        log_subprocess_output(process_output)
    except (OSError, CalledProcessError) as exception:
        logging.info('Exception occured: ' + str(exception))
        logging.info('Subprocess failed')
        return False
    else:
        # no exception was raised
        logging.info('Subprocess finished')

    return True