66 lines
2 KiB
Python
66 lines
2 KiB
Python
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#
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# shutup.py: context manager for ignoring overly verbose output
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#
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# Copyright (C) 2015 Red Hat, Inc.
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#
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# This program is free software; you can redistribute it and/or modify
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# it under the terms of the GNU Lesser General Public License as published
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# by the Free Software Foundation; either version 2.1 of the License, or
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# (at your option) any later version.
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#
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU Lesser General Public License for more details.
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#
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# You should have received a copy of the GNU Lesser General Public License
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# along with this program. If not, see <http://www.gnu.org/licenses/>.
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import os
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from contextlib import contextmanager
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@contextmanager
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def shutup():
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"""Run something with stdout and stderr redirected to /dev/null
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The redirections will be process-wide, so this is not recommended
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for multithreaded applications.
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"""
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# Wrap the whole thing a try-finally to ensure errors don't leak file descriptor
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old_stdout = None
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old_stderr = None
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devnull_fd = None
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try:
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# Save the current file descriptors
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old_stdout = os.dup(1)
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old_stderr = os.dup(2)
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# Redirect to /dev/null
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# Try to undo partial redirects if something goes wrong
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devnull_fd = os.open(os.devnull, os.O_WRONLY)
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try:
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os.dup2(devnull_fd, 1)
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os.dup2(devnull_fd, 2)
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except:
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os.dup2(old_stderr, 2)
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os.dup2(old_stdout, 1)
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raise
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# Run the body. Cleanup in finally to ensure stderr is restored before
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# an exception is raised.
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try:
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yield
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finally:
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os.dup2(old_stderr, 2)
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os.dup2(old_stdout, 1)
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finally:
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if old_stdout is not None:
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os.close(old_stdout)
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if old_stderr is not None:
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os.close(old_stderr)
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if devnull_fd is not None:
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os.close(devnull_fd)
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