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Python wrapper of tee - read from given input file descriptors and write to standard output and files.
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| # The MIT License (MIT) | |
| # | |
| # Copyright (c) 2021 Ivan Grynko | |
| # | |
| # Permission is hereby granted, free of charge, to any person obtaining a copy | |
| # of this software and associated documentation files (the "Software"), to deal | |
| # in the Software without restriction, including without limitation the rights | |
| # to use, copy, modify, merge, publish, distribute, sublicense, and/or sell | |
| # copies of the Software, and to permit persons to whom the Software is | |
| # furnished to do so, subject to the following conditions: | |
| # | |
| # The above copyright notice and this permission notice shall be included in | |
| # all copies or substantial portions of the Software. | |
| # | |
| # THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR | |
| # IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, | |
| # FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE | |
| # AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER | |
| # LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, | |
| # OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN | |
| # THE SOFTWARE. | |
| import os | |
| import sys | |
| import subprocess | |
| import logging | |
| import functools | |
| from typing import Iterable | |
| class Tee: | |
| """ | |
| Tee - read from given inputs and write to standard output and files. | |
| """ | |
| def __init__(self, in_files: Iterable[int], out_files: Iterable[str], mute: bool = False): | |
| """ | |
| Args: | |
| in_files: input file descriptors. | |
| out_files: output file names. | |
| mute: whether to mute duplication to stdout. Defaults to False. | |
| """ | |
| if not in_files: | |
| raise ValueError('At least one input file descriptor must be specified.') | |
| self.in_files = in_files | |
| self.out_files = out_files | |
| self.mute = mute | |
| @property | |
| def logger(self): | |
| return logging.getLogger('Tee') | |
| @property | |
| def stdin(self): | |
| if self.tee: | |
| return self.tee.stdin | |
| def start(self): | |
| """Start capturing input files.""" | |
| self.tee = subprocess.Popen( | |
| ["tee", *self.out_files], | |
| stdin=subprocess.PIPE, | |
| stdout=subprocess.DEVNULL if self.mute else None | |
| ) | |
| self._saved_fds = [] | |
| for fd in self.in_files: | |
| self._saved_fds.append(os.dup(fd)) | |
| os.dup2(self.tee.stdin.fileno(), fd) | |
| def stop(self, timeout=5): | |
| """Stop capturing input files. | |
| Args: | |
| timeout: seconds to wait subprocess to exit gracefully. | |
| """ | |
| if self.tee: | |
| self.tee.stdin.close() | |
| # close all fds | |
| for fd_src, fd_dst in zip(self._saved_fds, self.in_files): | |
| os.dup2(fd_src, fd_dst) | |
| os.close(fd_src) | |
| # terminate tee | |
| try: | |
| self.tee.wait(timeout=timeout) | |
| except subprocess.TimeoutExpired: | |
| self.logger.warning("tee process didn't quit gracefully, terminating...") | |
| self.tee.terminate() | |
| self.tee = None | |
| def __enter__(self, *args, **kwargs): | |
| self.start() | |
| return self | |
| def __exit__(self, *args, **kwargs): | |
| self.stop() | |
| def tee(in_files: Iterable[int], out_files: Iterable[str], mute: bool = False): | |
| """Tee decorator. | |
| Typical usage: | |
| @tee(in_files=[sys.stdout.fileno()], out_files=['output.log']) | |
| def func(): | |
| print('I need the line in stdout as well as in output.log') | |
| """ | |
| def factory(fn): | |
| @functools.wraps(fn) | |
| def wrapper(*args, **kwargs): | |
| with Tee(in_files, out_files, mute): | |
| return fn(*args, **kwargs) | |
| return wrapper | |
| return factory | |
| tee_stdout = functools.partial(tee, (sys.stdout.fileno(),)) | |
| tee_stderr = functools.partial(tee, (sys.stderr.fileno(),)) | |
| tee_stdall = functools.partial(tee, (sys.stdout.fileno(), sys.stderr.fileno(),)) |
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