| #!/usr/bin/env python |
| # Copyright (c) 2011 The Chromium OS Authors. All rights reserved. |
| # Use of this source code is governed by a BSD-style license that can be |
| # found in the LICENSE file. |
| # |
| # Backport of subprocess.check_output from python2.7 |
| # http://svn.python.org/view/*checkout*/python/tags/r271/Lib/subprocess.py |
| # |
| # Headers for that file are: |
| # subprocess - Subprocesses with accessible I/O streams |
| # |
| # For more information about this module, see PEP 324. |
| # |
| # This module should remain compatible with Python 2.2, see PEP 291. |
| # |
| # Copyright (c) 2003-2005 by Peter Astrand <astrand@lysator.liu.se> |
| # |
| # Licensed to PSF under a Contributor Agreement. |
| # See http://www.python.org/2.4/license for licensing details. |
| |
| import subprocess |
| import unittest |
| |
| |
| def check_output(*popenargs, **kwargs): |
| r"""Run command with arguments and return its output as a byte string. |
| |
| If the exit code was non-zero it raises a CalledProcessError. The |
| CalledProcessError object will have the return code in the returncode |
| attribute and output in the output attribute. |
| |
| The arguments are the same as for the Popen constructor. Example: |
| |
| >>> check_output(["ls", "-l", "/dev/null"]) |
| 'crw-rw-rw- 1 root root 1, 3 Oct 18 2007 /dev/null\n' |
| |
| The stdout argument is not allowed as it is used internally. |
| To capture standard error in the result, use stderr=STDOUT. |
| |
| >>> check_output(["/bin/sh", "-c", |
| ... "ls -l non_existent_file ; exit 0"], |
| ... stderr=STDOUT) |
| 'ls: non_existent_file: No such file or directory\n' |
| """ |
| if 'stdout' in kwargs: |
| raise ValueError('stdout argument not allowed, it will be overridden.') |
| process = subprocess.Popen(stdout=subprocess.PIPE, *popenargs, **kwargs) |
| output, unused_err = process.communicate() |
| retcode = process.poll() |
| if retcode: |
| cmd = kwargs.get("args") |
| if cmd is None: |
| cmd = popenargs[0] |
| raise subprocess.CalledProcessError(retcode, cmd) |
| return output |
| |
| |
| class CheckOutputTester(unittest.TestCase): |
| def test_check_output(self): |
| self.assertRaises(subprocess.CalledProcessError, |
| check_output, '/bin/false') |
| |
| self.assertRaises(ValueError, |
| check_output, ['/bin/true'], stdout='/tmp/nonexistant') |
| |
| self.assertEqual('hello\n', |
| check_output(['/bin/echo', 'hello'])) |
| |
| echoer = subprocess.Popen(['/bin/echo', 'hello'], stdout=subprocess.PIPE) |
| self.assertEqual('hello\n', |
| check_output(['/bin/cat'], stdin=echoer.stdout)) |
| |
| if __name__ == '__main__': |
| unittest.main() |