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Re: [Qemu-devel] [PATCH v7 02/11] qemu.py: avoid writing to stdout/stder
From: |
Fam Zheng |
Subject: |
Re: [Qemu-devel] [PATCH v7 02/11] qemu.py: avoid writing to stdout/stderr |
Date: |
Tue, 22 Aug 2017 18:24:56 +0800 |
User-agent: |
Mutt/1.8.3 (2017-05-23) |
On Fri, 08/18 19:05, Amador Pahim wrote:
> This module should not write directly to stdout/stderr. Instead, it
> should either raise exceptions or just log the messages and let the
> callers handle them and decide what to do. For example, scripts could
> choose to send the log messages stderr or/and write them to a file if
> verbose or debugging mode is enabled.
>
> This patch replaces the writes to stderr by an exception in the
> send_fd_scm() when _socket_scm_helper is not set or not present. In the
> same method, the subprocess Popen will now redirect the stdout/stderr to
> logging.debug instead of writing to system stderr. As consequence, since
> the Popen.communicate() is now used (in order to get the stdout), the
> further call to wait() became redundant and was replaced by
> Popen.returncode.
>
> The shutdown() message on negative exit code will now be logged
> to logging.debug instead of written to system stderr.
>
> Signed-off-by: Amador Pahim <address@hidden>
> ---
> scripts/qemu.py | 29 +++++++++++++++++++++--------
> 1 file changed, 21 insertions(+), 8 deletions(-)
>
> diff --git a/scripts/qemu.py b/scripts/qemu.py
> index 0ae5d39414..ef531bb23b 100644
> --- a/scripts/qemu.py
> +++ b/scripts/qemu.py
> @@ -13,6 +13,7 @@
> #
>
> import errno
> +import logging
> import string
> import os
> import sys
> @@ -20,6 +21,15 @@ import subprocess
> import qmp.qmp
>
>
> +LOG = logging.getLogger(__name__)
Previously the messages written to sys.stderr always get printed, now it depends
on the log level and IIUC debug messages are not printed by default. Should
LOG.warn be used to replace sys.stderr instead of LOG.debug?
> +
> +
> +class QEMUMachineError(Exception):
> + """
> + Exception called when an error in QEMUMachine happens.
> + """
> +
> +
> class QEMUMachine(object):
> '''A QEMU VM'''
>
> @@ -62,18 +72,20 @@ class QEMUMachine(object):
> # In iotest.py, the qmp should always use unix socket.
> assert self._qmp.is_scm_available()
> if self._socket_scm_helper is None:
> - print >>sys.stderr, "No path to socket_scm_helper set"
> - return -1
> + raise QEMUMachineError("No path to socket_scm_helper set")
> if os.path.exists(self._socket_scm_helper) == False:
> - print >>sys.stderr, "%s does not exist" % self._socket_scm_helper
> - return -1
> + raise QEMUMachineError("%s does not exist" %
> self._socket_scm_helper)
> fd_param = ["%s" % self._socket_scm_helper,
> "%d" % self._qmp.get_sock_fd(),
> "%s" % fd_file_path]
> devnull = open('/dev/null', 'rb')
> - p = subprocess.Popen(fd_param, stdin=devnull, stdout=sys.stdout,
> - stderr=sys.stderr)
> - return p.wait()
> + p = subprocess.Popen(fd_param, stdin=devnull, stdout=subprocess.PIPE,
> + stderr=subprocess.STDOUT)
> + output = p.communicate()[0]
> + if output:
> + LOG.debug(output)
> +
> + return p.returncode
>
> @staticmethod
> def _remove_if_exists(path):
> @@ -154,7 +166,8 @@ class QEMUMachine(object):
>
> exitcode = self._popen.wait()
> if exitcode < 0:
> - sys.stderr.write('qemu received signal %i: %s\n' %
> (-exitcode, ' '.join(self._args)))
> + LOG.debug('qemu received signal %i: %s', -exitcode,
> + ' '.join(self._args))
> self._load_io_log()
> self._post_shutdown()
>
> --
> 2.13.5
>
Fam
[Qemu-devel] [PATCH v7 05/11] qemu.py: cleanup redundant calls in launch(), Amador Pahim, 2017/08/18
[Qemu-devel] [PATCH v7 04/11] qemu.py: use poll() instead of 'returncode', Amador Pahim, 2017/08/18
[Qemu-devel] [PATCH v7 11/11] qemu.py: refactor launch(), Amador Pahim, 2017/08/18
[Qemu-devel] [PATCH v7 08/11] qemu.py: make sure we only remove files we create, Amador Pahim, 2017/08/18
[Qemu-devel] [PATCH v7 09/11] qemu.py: launch vm only if it's not running, Amador Pahim, 2017/08/18