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# arch-tag: 0abcff18-da5d-49f0-a03e-1d866a86b5cd
# Copyright (C) 2004 Canonical Ltd.
# Author: David Allouche <david@canonical.com>
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
"""Twisted process handling
The name of this module, "knotted", was suggested by Andrew Bennetts
as a way to avoid the name clash with the"twisted" top-level package::
<spiv> I'd say "knotted" would be good.
<spiv> And then you can tell people to "get knotted" ;)
I disclaim all responsibility for the bad taste of Twisted developers.
"""
import Queue
from twisted.internet import protocol
from arch import errors
import commandline
def make_exec_problem(data, command, args, expected, chdir):
status, signal, error = data
proc = DummyProcess(command, args, expected, chdir, status, signal, error)
return errors.ExecProblem(proc)
class TwistedSpawningStrategy(commandline.SpawningStrategy):
def __init__(self, command, logger):
self._command = command
self._logger = logger
def _spawn(self, args, chdir):
if __debug__:
from twisted.python import threadable
assert not threadable.isInIOThread()
from twisted.internet import reactor
# The queue size must be unlimited, otherwise the blocking
# put() in the reactor could cause a deadlock.
queue = Queue.Queue(0) # unlimited queue
process_protocol = ProcessProtocol(queue)
argv = [self._command]
argv.extend(args)
reactor.callFromThread(
reactor.spawnProcess,
process_protocol, self._command, args=argv, env=None, path=chdir)
return queue
def status_cmd(self, args, chdir, expected):
queue = self._spawn(args, chdir)
while True:
msg = queue.get(block=True)
if msg[0] == 'start':
self._logger.log_command(self._command, args)
elif msg[0] == 'output':
text = ''.join(msg[1])
self._logger.log_output(text)
elif msg[0] == 'error':
text = ''.join(msg[1])
self._logger.log_error(text)
elif msg[0] == 'terminate':
if msg[1] in expected and msg[2] is None:
return msg[1]
else:
raise make_exec_problem(
msg[1:], self._command, args, expected, chdir)
else:
raise AssertionError('bad message: %r', msg)
def sequence_cmd(self, args, chdir, expected):
queue = self._spawn(args, chdir)
return SequenceCmd(
queue, self._command, args, chdir, expected, self._logger)
def status_text_cmd(self, args, chdir, expected):
queue = self._spawn(args, chdir)
seq = SequenceCmd(
queue, self._command, args, chdir, expected, self._logger)
seq.strip = False
text = ''.join(seq)
return seq.status, text
class SequenceCmd(object):
def __init__(self, queue, command, args, chdir, expected, logger):
self._queue = queue
self._command = command
self._logger = logger
self._args = args
self._chdir = chdir
self._expected = expected
self._buffer = []
self._status = None
self.finished = False
self.strip = True
def __iter__(self):
return self
def next(self):
while True:
if self.finished:
raise StopIteration
if self._buffer:
line = self._buffer.pop(0)
if self.strip:
return line.rstrip('\n')
else:
return line
msg = self._queue.get(block=True)
if msg[0] == 'start':
self._logger.log_command(self._command, self._args)
elif msg[0] == 'output':
self._buffer = msg[1] + self._buffer
elif msg[0] == 'error':
text = ''.join(msg[1])
self._logger.log_error(text)
elif msg[0] == 'terminate':
self.finished = True
if msg[1] in self._expected and msg[2] is None:
self._status = msg[1]
else:
raise make_exec_problem(
msg[1:], self._command, self._args,
self._expected, self._chdir)
else:
raise AssertionError('bad message: %r', msg)
def _get_status(self):
if self._status is None:
raise AttributeError, "no status, process has not finished"
return self._status
status = property(_get_status)
class DummyProcess(object):
"""Dummy object providing the same interface as `forkexec.ChildProcess`."""
def __init__(self, command, args, expected, chdir, status, signal, error):
self.command = command
self.args = args
self.chdir = chdir
self.expected = expected
self.error = ''.join(error)
self.status = status
self.signal = signal
class ProcessProtocol(protocol.ProcessProtocol):
def __init__(self, queue):
self.__queue = queue
self.__out_buffer = str()
self.__err_buffer = str()
self.error_lines = []
self.status = None
def connectionMade(self):
"""The process has started."""
self.__queue.put(('start',), block=True)
def __send_output(self, lines):
self.__queue.put(('output', lines), block=True)
def __send_error(self, lines):
self.__queue.put(('error', lines), block=True)
def outReceived(self, data):
"""The process has produced data on standard output."""
data = self.__out_buffer + data
lines = data.splitlines(True)
if lines[-1].endswith('\n'):
self.__out_buffer = str()
complete_lines = lines
else:
self.__out_buffer = lines[-1]
complete_lines = lines[:-1]
self.__send_output(complete_lines)
def errReceived(self, data):
"""The process has produced data on standard error."""
data = self.__err_buffer + data
lines = data.splitlines(True)
if lines[-1].endswith('\n'):
self.__err_buffer = str()
complete_lines = lines
else:
self.__err_buffer = lines[-1]
complete_lines = lines[:-1]
self.__send_error(complete_lines)
self.error_lines.extend(complete_lines)
def outConnectionLost(self):
"""The process has closed standard output."""
if self.__out_buffer:
self.__send_output([self.__out_buffer])
self.__out_buffer = str()
def errConnectionLost(self):
"""The process has closed standard error."""
if self.__err_buffer:
self.__send_error([self.__err_buffer])
self.error_lines.append(self.__err_buffer)
self.__err_buffer = str()
def processEnded(self, reason):
"""The process has terminated."""
signal = reason.value.signal
status = reason.value.exitCode
msg = ('terminate', status, signal, self.error_lines)
self.__queue.put(msg, block=True)
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