beremiz

fix issue with sometimes wrong return code of ProcessLogger

2016-04-28, Andrey Skvortsov
d7f474d10210
fix issue with sometimes wrong return code of ProcessLogger


As a result of wrong return code Beremiz gives folowing traceback:
Traceback (most recent call last):
File "./Beremiz.py", line 850, in OnMenu
getattr(self.CTR, method)()
File "/home/developer/WorkData/PLC/beremiz/beremiz/ProjectController.py", line 925, in _Build
IECGenRes = self._Generate_SoftPLC()
File "/home/developer/WorkData/PLC/beremiz/beremiz/ProjectController.py", line 568, in _Generate_SoftPLC
return self._Compile_ST_to_SoftPLC()
File "/home/developer/WorkData/PLC/beremiz/beremiz/ProjectController.py", line 661, in _Compile_ST_to_SoftPLC
C_files.remove("POUS.c")
ValueError: list.remove(x): x not in list

The problem is that both threads (for reading stdout and stderr) call self.Proc.poll(),
that updates internal returncode field. This call is done without any locking and the first thread gets correct result,
but other gets 0 as retval. If 0 gets thread, that afterwards calls callback finish, then wrong return code is returned
to the parent. Now only the thread with a callback polls for the return code, other thread just checked local value.

Additionally function spin() waits now until all threads finish reading their pipes, so the results are always correct.
#!/usr/bin/env python
# -*- coding: utf-8 -*-
#
#Copyright (C) 2015: Edouard TISSERANT
#
#See COPYING file for copyrights details.
#
#This library 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 2.1 of the License, or (at your option) any later version.
#
#This library 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 library; if not, write to the Free Software
#Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
import sys, traceback, atexit
#from twisted.python import log
from twisted.internet import reactor, threads
from autobahn.twisted import wamp
from autobahn.twisted.websocket import WampWebSocketClientFactory, connectWS
from autobahn.wamp import types
from autobahn.wamp.exception import TransportLost
from autobahn.wamp.serializer import MsgPackSerializer
from threading import Thread, Event
_WampSession = None
_WampConnection = None
_WampSessionEvent = Event()
class WampSession(wamp.ApplicationSession):
def onJoin(self, details):
global _WampSession, _WampSessionEvent
_WampSession = self
_WampSessionEvent.set()
print 'WAMP session joined for :', self.config.extra["ID"]
def onLeave(self, details):
global _WampSession, _WampSessionEvent
_WampSessionEvent.clear()
_WampSession = None
print 'WAMP session left'
PLCObjDefaults = { "StartPLC": False,
"GetTraceVariables" : ("Broken",None),
"GetPLCstatus" : ("Broken",None),
"RemoteExec" : (-1, "RemoteExec script failed!")}
def WAMP_connector_factory(uri, confnodesroot):
"""
WAMP://127.0.0.1:12345/path#realm#ID
WAMPS://127.0.0.1:12345/path#realm#ID
"""
servicetype, location = uri.split("://")
urlpath, realm, ID = location.split('#')
urlprefix = {"WAMP":"ws",
"WAMPS":"wss"}[servicetype]
url = urlprefix+"://"+urlpath
def RegisterWampClient():
## start logging to console
# log.startLogging(sys.stdout)
# create a WAMP application session factory
component_config = types.ComponentConfig(
realm = realm,
extra = {"ID":ID})
session_factory = wamp.ApplicationSessionFactory(
config = component_config)
session_factory.session = WampSession
# create a WAMP-over-WebSocket transport client factory
transport_factory = WampWebSocketClientFactory(
session_factory,
url = url,
serializers = [MsgPackSerializer()],
debug = False,
debug_wamp = False)
# start the client from a Twisted endpoint
conn = connectWS(transport_factory)
confnodesroot.logger.write(_("WAMP connecting to URL : %s\n")%url)
return conn
AddToDoBeforeQuit = confnodesroot.AppFrame.AddToDoBeforeQuit
def ThreadProc():
global _WampConnection
_WampConnection = RegisterWampClient()
AddToDoBeforeQuit(reactor.stop)
reactor.run(installSignalHandlers=False)
def WampSessionProcMapper(funcname):
wampfuncname = '.'.join((ID,funcname))
def catcher_func(*args,**kwargs):
global _WampSession
if _WampSession is not None :
try:
return threads.blockingCallFromThread(
reactor, _WampSession.call, wampfuncname,
*args,**kwargs)
except TransportLost, e:
confnodesroot.logger.write_error("Connection lost!\n")
confnodesroot._SetConnector(None)
except Exception,e:
errmess = traceback.format_exc()
confnodesroot.logger.write_error(errmess+"\n")
print errmess
#confnodesroot._SetConnector(None)
return PLCObjDefaults.get(funcname)
return catcher_func
class WampPLCObjectProxy(object):
def __init__(self):
global _WampSessionEvent, _WampConnection
if not reactor.running:
Thread(target=ThreadProc).start()
else:
_WampConnection = threads.blockingCallFromThread(
reactor, RegisterWampClient)
if not _WampSessionEvent.wait(5):
_WampConnection = stopConnecting()
raise Exception, _("WAMP connection timeout")
def __del__(self):
global _WampConnection
_WampConnection.disconnect()
#
# reactor.stop()
def __getattr__(self, attrName):
member = self.__dict__.get(attrName, None)
if member is None:
member = WampSessionProcMapper(attrName)
self.__dict__[attrName] = member
return member
# Try to get the proxy object
try :
return WampPLCObjectProxy()
except Exception, msg:
confnodesroot.logger.write_error(_("WAMP connection to '%s' failed.\n")%location)
confnodesroot.logger.write_error(traceback.format_exc())
return None