基于亚当·罗森菲尔德的代码 https://stackoverflow.com/a/7730201/190597, 你可以
- use
select.select
阻塞直到有输出可供读取proc.stdout
or proc.stderr
,
- 读取并记录该输出,然后
- 重复直到该过程完成。
请注意,以下写入/tmp/test.log
并运行命令ls -laR /tmp
。更改以满足您的需求。
(PS:通常/tmp包含普通用户无法读取的目录,因此运行ls -laR /tmp
向 stdout 和 stderr 生成输出。下面的代码在生成这两个流时正确地交错它们。)
import logging
import subprocess
import shlex
import select
import fcntl
import os
import errno
import contextlib
logger = logging.getLogger(__name__)
def make_async(fd):
'''add the O_NONBLOCK flag to a file descriptor'''
fcntl.fcntl(fd, fcntl.F_SETFL, fcntl.fcntl(fd, fcntl.F_GETFL) | os.O_NONBLOCK)
def read_async(fd):
'''read some data from a file descriptor, ignoring EAGAIN errors'''
try:
return fd.read()
except IOError, e:
if e.errno != errno.EAGAIN:
raise e
else:
return ''
def log_fds(fds):
for fd in fds:
out = read_async(fd)
if out:
logger.info(out)
@contextlib.contextmanager
def plain_logger():
root = logging.getLogger()
hdlr = root.handlers[0]
formatter_orig = hdlr.formatter
hdlr.setFormatter(logging.Formatter('%(message)s'))
yield
hdlr.setFormatter(formatter_orig)
def main():
# fmt = '%(name)-12s: %(levelname)-8s %(message)s'
logging.basicConfig(filename = '/tmp/test.log', mode = 'w',
level = logging.DEBUG)
logger.info("Started")
cmdStr = 'ls -laR /tmp'
with plain_logger():
proc = subprocess.Popen(shlex.split(cmdStr),
stdout = subprocess.PIPE, stderr = subprocess.PIPE)
# without `make_async`, `fd.read` in `read_async` blocks.
make_async(proc.stdout)
make_async(proc.stderr)
while True:
# Wait for data to become available
rlist, wlist, xlist = select.select([proc.stdout, proc.stderr], [], [])
log_fds(rlist)
if proc.poll() is not None:
# Corner case: check if more output was created
# between the last call to read_async and now
log_fds([proc.stdout, proc.stderr])
break
logger.info("Done")
if __name__ == '__main__':
main()
Edit:
您可以重定向stdout
and stderr
to logfile = open('/tmp/test.log', 'a')
。
然而,这样做的一个小困难是,任何同时写入的记录器处理程序/tmp/test.log
将不知道子进程正在写入什么,因此日志文件可能会出现乱码。
如果在子进程执行其业务时不进行日志记录调用,则唯一的问题是记录器处理程序在子进程完成后在文件中的位置错误。这可以通过调用来修复
handler.stream.seek(0, 2)
因此处理程序将在文件末尾恢复写入。
import logging
import subprocess
import contextlib
import shlex
logger = logging.getLogger(__name__)
@contextlib.contextmanager
def suspended_logger():
root = logging.getLogger()
handler = root.handlers[0]
yield
handler.stream.seek(0, 2)
def main():
logging.basicConfig(filename = '/tmp/test.log', filemode = 'w',
level = logging.DEBUG)
logger.info("Started")
with suspended_logger():
cmdStr = 'test2.py 1>>/tmp/test.log 2>&1'
logfile = open('/tmp/test.log', 'a')
proc = subprocess.Popen(shlex.split(cmdStr),
stdout = logfile,
stderr = logfile)
proc.communicate()
logger.info("Done")
if __name__ == '__main__':
main()