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Diffstat (limited to 'nova/process.py')
| -rw-r--r-- | nova/process.py | 209 |
1 files changed, 0 insertions, 209 deletions
diff --git a/nova/process.py b/nova/process.py deleted file mode 100644 index b33df048b..000000000 --- a/nova/process.py +++ /dev/null @@ -1,209 +0,0 @@ -# vim: tabstop=4 shiftwidth=4 softtabstop=4 - -# Copyright 2010 United States Government as represented by the -# Administrator of the National Aeronautics and Space Administration. -# Copyright 2010 FathomDB Inc. -# All Rights Reserved. -# -# Licensed under the Apache License, Version 2.0 (the "License"); you may -# not use this file except in compliance with the License. You may obtain -# a copy of the License at -# -# http://www.apache.org/licenses/LICENSE-2.0 -# -# Unless required by applicable law or agreed to in writing, software -# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT -# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the -# License for the specific language governing permissions and limitations -# under the License. - -""" -Process pool using twisted threading -""" - -import logging -import StringIO - -from twisted.internet import defer -from twisted.internet import error -from twisted.internet import protocol -from twisted.internet import reactor - -from nova import flags -from nova.exception import ProcessExecutionError - -FLAGS = flags.FLAGS -flags.DEFINE_integer('process_pool_size', 4, - 'Number of processes to use in the process pool') - - -# This is based on _BackRelay from twister.internal.utils, but modified to -# capture both stdout and stderr, without odd stderr handling, and also to -# handle stdin -class BackRelayWithInput(protocol.ProcessProtocol): - """ - Trivial protocol for communicating with a process and turning its output - into the result of a L{Deferred}. - - @ivar deferred: A L{Deferred} which will be called back with all of stdout - and all of stderr as well (as a tuple). C{terminate_on_stderr} is true - and any bytes are received over stderr, this will fire with an - L{_ProcessExecutionError} instance and the attribute will be set to - C{None}. - - @ivar onProcessEnded: If C{terminate_on_stderr} is false and bytes are - received over stderr, this attribute will refer to a L{Deferred} which - will be called back when the process ends. This C{Deferred} is also - associated with the L{_ProcessExecutionError} which C{deferred} fires - with earlier in this case so that users can determine when the process - has actually ended, in addition to knowing when bytes have been - received via stderr. - """ - - def __init__(self, deferred, cmd, started_deferred=None, - terminate_on_stderr=False, check_exit_code=True, - process_input=None): - self.deferred = deferred - self.cmd = cmd - self.stdout = StringIO.StringIO() - self.stderr = StringIO.StringIO() - self.started_deferred = started_deferred - self.terminate_on_stderr = terminate_on_stderr - self.check_exit_code = check_exit_code - self.process_input = process_input - self.on_process_ended = None - - def _build_execution_error(self, exit_code=None): - return ProcessExecutionError(cmd=self.cmd, - exit_code=exit_code, - stdout=self.stdout.getvalue(), - stderr=self.stderr.getvalue()) - - def errReceived(self, text): - self.stderr.write(text) - if self.terminate_on_stderr and (self.deferred is not None): - self.on_process_ended = defer.Deferred() - self.deferred.errback(self._build_execution_error()) - self.deferred = None - self.transport.loseConnection() - - def outReceived(self, text): - self.stdout.write(text) - - def processEnded(self, reason): - if self.deferred is not None: - stdout, stderr = self.stdout.getvalue(), self.stderr.getvalue() - exit_code = reason.value.exitCode - if self.check_exit_code and exit_code != 0: - self.deferred.errback(self._build_execution_error(exit_code)) - else: - try: - if self.check_exit_code: - reason.trap(error.ProcessDone) - self.deferred.callback((stdout, stderr)) - except: - # NOTE(justinsb): This logic is a little suspicious to me. - # If the callback throws an exception, then errback will - # be called also. However, this is what the unit tests - # test for. - exec_error = self._build_execution_error(exit_code) - self.deferred.errback(exec_error) - elif self.on_process_ended is not None: - self.on_process_ended.errback(reason) - - def connectionMade(self): - if self.started_deferred: - self.started_deferred.callback(self) - if self.process_input: - self.transport.write(str(self.process_input)) - self.transport.closeStdin() - - -def get_process_output(executable, args=None, env=None, path=None, - process_reactor=None, check_exit_code=True, - process_input=None, started_deferred=None, - terminate_on_stderr=False): - if process_reactor is None: - process_reactor = reactor - args = args and args or () - env = env and env and {} - deferred = defer.Deferred() - cmd = executable - if args: - cmd = " ".join([cmd] + args) - logging.debug("Running cmd: %s", cmd) - process_handler = BackRelayWithInput( - deferred, - cmd, - started_deferred=started_deferred, - check_exit_code=check_exit_code, - process_input=process_input, - terminate_on_stderr=terminate_on_stderr) - # NOTE(vish): commands come in as unicode, but self.executes needs - # strings or process.spawn raises a deprecation warning - executable = str(executable) - if not args is None: - args = [str(x) for x in args] - process_reactor.spawnProcess(process_handler, executable, - (executable,) + tuple(args), env, path) - return deferred - - -class ProcessPool(object): - """ A simple process pool implementation using Twisted's Process bits. - - This is pretty basic right now, but hopefully the API will be the correct - one so that it can be optimized later. - """ - def __init__(self, size=None): - self.size = size and size or FLAGS.process_pool_size - self._pool = defer.DeferredSemaphore(self.size) - - def simple_execute(self, cmd, **kw): - """ Weak emulation of the old utils.execute() function. - - This only exists as a way to quickly move old execute methods to - this new style of code. - - NOTE(termie): This will break on args with spaces in them. - """ - parsed = cmd.split(' ') - executable, args = parsed[0], parsed[1:] - return self.execute(executable, args, **kw) - - def execute(self, *args, **kw): - deferred = self._pool.acquire() - - def _associate_process(proto): - deferred.process = proto.transport - return proto.transport - - started = defer.Deferred() - started.addCallback(_associate_process) - kw.setdefault('started_deferred', started) - - deferred.process = None - deferred.started = started - - deferred.addCallback(lambda _: get_process_output(*args, **kw)) - deferred.addBoth(self._release) - return deferred - - def _release(self, retval=None): - self._pool.release() - return retval - - -class SharedPool(object): - _instance = None - - def __init__(self): - if SharedPool._instance is None: - self.__class__._instance = ProcessPool() - - def __getattr__(self, key): - return getattr(self._instance, key) - - -def simple_execute(cmd, **kwargs): - return SharedPool().simple_execute(cmd, **kwargs) |