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#!/usr/bin/env python
#
# Copyright (c) 2016 ARM Limited
# All rights reserved
#
# The license below extends only to copyright in the software and shall
# not be construed as granting a license to any other intellectual
# property including but not limited to intellectual property relating
# to a hardware implementation of the functionality of the software
# licensed hereunder. You may use the software subject to the license
# terms below provided that you ensure that this notice is replicated
# unmodified and in its entirety in all distributions of the software,
# modified or unmodified, in source code or in binary form.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are
# met: redistributions of source code must retain the above copyright
# notice, this list of conditions and the following disclaimer;
# redistributions in binary form must reproduce the above copyright
# notice, this list of conditions and the following disclaimer in the
# documentation and/or other materials provided with the distribution;
# neither the name of the copyright holders nor the names of its
# contributors may be used to endorse or promote products derived from
# this software without specific prior written permission.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#
# Authors: Andreas Sandberg
import subprocess
from threading import Timer
import time
class CallTimeoutException(Exception):
"""Exception that indicates that a process call timed out"""
def __init__(self, status, stdout, stderr):
self.status = status
self.stdout = stdout
self.stderr = stderr
class ProcessHelper(subprocess.Popen):
"""Helper class to run child processes.
This class wraps a subprocess.Popen class and adds support for
using it in a with block. When the process goes out of scope, it's
automatically terminated.
with ProcessHelper(["/bin/ls"], stdout=subprocess.PIPE) as p:
return p.call()
"""
def __init__(self, *args, **kwargs):
super(ProcessHelper, self).__init__(*args, **kwargs)
def _terminate_nicely(self, timeout=5):
def on_timeout():
self.kill()
if self.returncode is not None:
return self.returncode
timer = Timer(timeout, on_timeout)
self.terminate()
status = self.wait()
timer.cancel()
return status
def __enter__(self):
return self
def __exit__(self, exc_type, exc_value, traceback):
if self.returncode is None:
self._terminate_nicely()
def call(self, timeout=0):
self._timeout = False
def on_timeout():
self._timeout = True
self._terminate_nicely()
status, stdout, stderr = None, None, None
timer = Timer(timeout, on_timeout)
if timeout:
timer.start()
stdout, stderr = self.communicate()
status = self.wait()
timer.cancel()
if self._timeout:
self._terminate_nicely()
raise CallTimeoutException(self.returncode, stdout, stderr)
else:
return status, stdout, stderr
if __name__ == "__main__":
# Run internal self tests to ensure that the helpers are working
# properly. The expected output when running this script is
# "SUCCESS!".
cmd_foo = [ "/bin/echo", "-n", "foo" ]
cmd_sleep = [ "/bin/sleep", "10" ]
# Test that things don't break if the process hasn't been started
with ProcessHelper(cmd_foo) as p:
pass
with ProcessHelper(cmd_foo, stdout=subprocess.PIPE) as p:
status, stdout, stderr = p.call()
assert stdout == "foo"
assert status == 0
try:
with ProcessHelper(cmd_sleep) as p:
status, stdout, stderr = p.call(timeout=1)
assert False, "Timeout not triggered"
except CallTimeoutException:
pass
print "SUCCESS!"
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