runtime/NevowServer.py
author Andrey Skvortsov <andrej.skvortzov@gmail.com>
Thu, 28 Apr 2016 13:05:57 +0300
changeset 1507 d7f474d10210
parent 1453 f31353cac197
child 1511 91538d0c242c
permissions -rw-r--r--
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.
import os
from nevow import rend, appserver, inevow, tags, loaders, athena
from nevow.page import renderer
from twisted.python import util
from twisted.internet import reactor

xhtml_header = '''<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN"
"http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
'''

WorkingDir = None

class PLCHMI(athena.LiveElement):

    initialised = False

    def HMIinitialised(self, result):
        self.initialised = True

    def HMIinitialisation(self):
        self.HMIinitialised(None)

class DefaultPLCStartedHMI(PLCHMI):
    docFactory = loaders.stan(tags.div(render=tags.directive('liveElement'))[
                                            tags.h1["PLC IS NOW STARTED"],
                                            ])

class PLCStoppedHMI(PLCHMI):
    docFactory = loaders.stan(tags.div(render=tags.directive('liveElement'))[
                                            tags.h1["PLC IS STOPPED"],
                                            ])

class MainPage(athena.LiveElement):
    jsClass = u"WebInterface.PLC"
    docFactory = loaders.stan(tags.div(render=tags.directive('liveElement'))[
                                                    tags.div(id='content')[
                                                    tags.div(render = tags.directive('PLCElement')),
                                                    ]])

    def __init__(self, *a, **kw):
        athena.LiveElement.__init__(self, *a, **kw)
        self.pcl_state = False
        self.HMI = None
        self.resetPLCStartedHMI()

    def setPLCState(self, state):
        self.pcl_state = state
        if self.HMI is not None:
            self.callRemote('updateHMI')

    def setPLCStartedHMI(self, hmi):
        self.PLCStartedHMIClass = hmi

    def resetPLCStartedHMI(self):
        self.PLCStartedHMIClass = DefaultPLCStartedHMI

    def getHMI(self):
        return self.HMI

    def HMIexec(self, function, *args, **kwargs):
        if self.HMI is not None:
            getattr(self.HMI, function, lambda:None)(*args, **kwargs)
    athena.expose(HMIexec)

    def resetHMI(self):
        self.HMI = None

    def PLCElement(self, ctx, data):
        return self.getPLCElement()
    renderer(PLCElement)

    def getPLCElement(self):
        self.detachFragmentChildren()
        if self.pcl_state:
            f = self.PLCStartedHMIClass()
        else:
            f = PLCStoppedHMI()
        f.setFragmentParent(self)
        self.HMI = f
        return f
    athena.expose(getPLCElement)

    def detachFragmentChildren(self):
        for child in self.liveFragmentChildren[:]:
            child.detach()

class WebInterface(athena.LivePage):

    docFactory = loaders.stan([tags.raw(xhtml_header),
                                tags.html(xmlns="http://www.w3.org/1999/xhtml")[
                                    tags.head(render=tags.directive('liveglue')),
                                    tags.body[
                                        tags.div[
                                                tags.div( render = tags.directive( "MainPage" ))
                                                ]]]])
    MainPage = MainPage()
    PLCHMI = PLCHMI

    def __init__(self, plcState=False, *a, **kw):
        super(WebInterface, self).__init__(*a, **kw)
        self.jsModules.mapping[u'WebInterface'] = util.sibpath(__file__, 'webinterface.js')
        self.plcState = plcState
        self.MainPage.setPLCState(plcState)

    def getHMI(self):
        return self.MainPage.getHMI()

    def LoadHMI(self, hmi, jsmodules):
        for name, path in jsmodules.iteritems():
            self.jsModules.mapping[name] = os.path.join(WorkingDir, path)
        self.MainPage.setPLCStartedHMI(hmi)

    def UnLoadHMI(self):
        self.MainPage.resetPLCStartedHMI()

    def PLCStarted(self):
        self.plcState = True
        self.MainPage.setPLCState(True)

    def PLCStopped(self):
        self.plcState = False
        self.MainPage.setPLCState(False)

    def renderHTTP(self, ctx):
        """
        Force content type to fit with SVG
        """
        req = inevow.IRequest(ctx)
        req.setHeader('Content-type', 'application/xhtml+xml')
        return super(WebInterface, self).renderHTTP(ctx)

    def render_MainPage(self, ctx, data):
        f = self.MainPage
        f.setFragmentParent(self)
        return ctx.tag[f]

    def child_(self, ctx):
        self.MainPage.detachFragmentChildren()
        return WebInterface(plcState=self.plcState)

    def beforeRender(self, ctx):
        d = self.notifyOnDisconnect()
        d.addErrback(self.disconnected)

    def disconnected(self, reason):
        self.MainPage.resetHMI()
        #print reason
        #print "We will be called back when the client disconnects"

def RegisterWebsite(port):
    website = WebInterface()
    site = appserver.NevowSite(website)

    listening = False
    reactor.listenTCP(port, site)
    print "Http interface port :",port
    return website

class statuslistener:
    def __init__(self, site):
        self.oldstate = None
        self.site = site

    def listen(self, state):
        if state != self.oldstate:
            action = {'Started': self.site.PLCStarted,
                      'Stopped': self.site.PLCStopped}.get(state, None)
            if action is not None: action ()
            self.oldstate = state

def website_statuslistener_factory(site):
    return statuslistener(site).listen