runtime/ServicePublisher.py
author Andrey Skvortsov <andrej.skvortzov@gmail.com>
Thu, 28 Apr 2016 13:05:57 +0300
changeset 1507 d7f474d10210
parent 763 c1104099c151
child 1571 486f94a8032c
permissions -rwxr-xr-x
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 -*-

#This file is part of Beremiz, a Integrated Development Environment for
#programming IEC 61131-3 automates supporting plcopen standard and CanFestival. 
#
#Copyright (C) 2007: Edouard TISSERANT and Laurent BESSARD
#
#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 socket, threading
from util import Zeroconf

service_type = '_PYRO._tcp.local.'

class ServicePublisher():
    def __init__(self):
        # type: fully qualified service type name
        self.serviceproperties = {'description':'Beremiz remote PLC'}
        
        self.name = None
        self.ip_32b = None
        self.port = None
        self.server = None
        self.service_name = None
        self.retrytimer = None
        
    def RegisterService(self, name, ip, port):
        try:
            self._RegisterService(name, ip, port)
        except Exception,e:
            self.retrytimer = threading.Timer(2,self.RegisterService,[name, ip, port])
            self.retrytimer.start() 

    def _RegisterService(self, name, ip, port):
        # name: fully qualified service name
        self.service_name = 'Beremiz_%s.%s'%(name,service_type)
        self.name = name
        self.port = port

        self.server = Zeroconf.Zeroconf(ip)
        print "MDNS brodcasting on :"+ip

        if ip == "0.0.0.0":
            ip = self.gethostaddr()
        print "MDNS brodcasted service address :"+ip
        self.ip_32b = socket.inet_aton(ip)

        self.server.registerService(
             Zeroconf.ServiceInfo(service_type,
                                  self.service_name,
                                  self.ip_32b,
                                  self.port,
                                  properties = self.serviceproperties))
        self.retrytimer=None
    
    def UnRegisterService(self):
        if self.retrytimer is not None:
            self.retrytimer.cancel()

        self.server.unregisterService(
                                      Zeroconf.ServiceInfo(service_type, 
                                                           self.service_name, 
                                                           self.ip_32b, 
                                                           self.port, 
                                                           properties = self.serviceproperties))
        self.server.close()
        self.server = None
    
    def gethostaddr(self, dst = '224.0.1.41'):
        s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
        try:
            s.connect((dst, 7))
            (host, port) = s.getsockname()
            s.close()
            if host != '0.0.0.0':
                return host
        except Exception,e:
            pass
        return socket.gethostbyname(socket.gethostname())