util/ProcessLogger.py
author Andrey Skvortsov <andrej.skvortzov@gmail.com>
Thu, 28 Apr 2016 13:05:57 +0300
changeset 1507 d7f474d10210
parent 1506 b9b8978dbc9d
child 1516 9db0b436fbb3
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.
#!/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 time
import wx
import subprocess, ctypes
from threading import Timer, Lock, Thread, Semaphore
import os, sys
if os.name == 'posix':
    from signal import SIGTERM, SIGKILL


class outputThread(Thread):
    """
    Thread is used to print the output of a command to the stdout
    """
    def __init__(self, Proc, fd, callback=None, endcallback=None):
        Thread.__init__(self)
        self.killed = False
        self.finished = False
        self.retval = None
        self.Proc = Proc
        self.callback = callback
        self.endcallback = endcallback
        self.fd = fd

    def run(self):
        outchunk = None
        self.retval = None
        while self.retval is None and not self.killed :
            if self.endcallback:
                self.retval = self.Proc.poll()
            else:
                self.retval = self.Proc.returncode
                
            outchunk = self.fd.readline()
            if self.callback : self.callback(outchunk)
        while outchunk != '' and not self.killed :
            outchunk = self.fd.readline()
            if self.callback : self.callback(outchunk)
        if self.endcallback:
            try:
                err = self.Proc.wait()
            except:
                err = self.retval
            self.finished = True
            self.endcallback(self.Proc.pid, err)

class ProcessLogger:
    def __init__(self, logger, Command, finish_callback = None,
                 no_stdout = False, no_stderr = False, no_gui = True,
                 timeout = None, outlimit = None, errlimit = None,
                 endlog = None, keyword = None, kill_it = False, cwd = None,
                 encoding = None):
        self.logger = logger
        if not isinstance(Command, list):
            self.Command_str = Command
            self.Command = []
            for i,word in enumerate(Command.replace("'",'"').split('"')):
                if i % 2 == 0:
                    word = word.strip()
                    if len(word) > 0:
                        self.Command.extend(word.split())
                else:
                    self.Command.append(word)
        else:
            self.Command = Command
            self.Command_str = subprocess.list2cmdline(self.Command)

        fsencoding = sys.getfilesystemencoding()

        if encoding is None:
            encoding = fsencoding
        self.Command = [self.Command[0].encode(fsencoding)]+map(
            lambda x: x.encode(encoding), self.Command[1:])

        self.finish_callback = finish_callback
        self.no_stdout = no_stdout
        self.no_stderr = no_stderr
        self.startupinfo = None
        self.errlen = 0
        self.outlen = 0
        self.errlimit = errlimit
        self.outlimit = outlimit
        self.exitcode = None
        self.outdata = []
        self.errdata = []
        self.keyword = keyword
        self.kill_it = kill_it
        self.finishsem = Semaphore(0)
        self.endlock = Lock()

        popenargs= {
               "cwd":os.getcwd() if cwd is None else cwd,
               "stdin":subprocess.PIPE,
               "stdout":subprocess.PIPE,
               "stderr":subprocess.PIPE}

        if no_gui == True and wx.Platform == '__WXMSW__':
            self.startupinfo = subprocess.STARTUPINFO()
            self.startupinfo.dwFlags |= subprocess.STARTF_USESHOWWINDOW
            popenargs["startupinfo"] = self.startupinfo
        elif wx.Platform == '__WXGTK__':
            popenargs["shell"] = False

        if timeout:
            self.timeout = Timer(timeout,self.endlog)
            self.timeout.start()
        else:
            self.timeout = None
            
        self.Proc = subprocess.Popen( self.Command, **popenargs )

        self.outt = outputThread(
                      self.Proc,
                      self.Proc.stdout,
                      self.output,
                      self.finish)
        self.outt.start()

        self.errt = outputThread(
                      self.Proc,
                      self.Proc.stderr,
                      self.errors)
        self.errt.start()


    def output(self,v):
        self.outdata.append(v)
        self.outlen += 1
        if not self.no_stdout:
            self.logger.write(v)
        if (self.keyword and v.find(self.keyword)!=-1) or (self.outlimit and self.outlen > self.outlimit):
            self.endlog()

    def errors(self,v):
        self.errdata.append(v)
        self.errlen += 1
        if not self.no_stderr:
            self.logger.write_warning(v)
        if self.errlimit and self.errlen > self.errlimit:
            self.endlog()

    def log_the_end(self,ecode,pid):
        self.logger.write(self.Command_str + "\n")
        self.logger.write_warning(_("exited with status %s (pid %s)\n")%(str(ecode),str(pid)))

    def finish(self, pid,ecode):
        if self.timeout:
            self.timeout.cancel()
        self.exitcode = ecode
        if self.exitcode != 0:
            self.log_the_end(ecode,pid)
        if self.finish_callback is not None:
            self.finish_callback(self,ecode,pid)
        self.finishsem.release()

    def kill(self,gently=True):
        self.outt.killed = True
        self.errt.killed = True
        if wx.Platform == '__WXMSW__':
            PROCESS_TERMINATE = 1
            handle = ctypes.windll.kernel32.OpenProcess(PROCESS_TERMINATE, False, self.Proc.pid)
            ctypes.windll.kernel32.TerminateProcess(handle, -1)
            ctypes.windll.kernel32.CloseHandle(handle)
        else:
            if gently:
                sig=SIGTERM
            else:
                sig=SIGKILL
            try:
                os.kill(self.Proc.pid, sig)
            except:
                pass
        self.outt.join()
        self.errt.join()

    def endlog(self):
        if self.endlock.acquire(False):
            self.finishsem.release()
            if not self.outt.finished and self.kill_it:
               self.kill()


    def spin(self):
        self.finishsem.acquire()
        self.outt.join()
        self.errt.join()
        return [self.exitcode, "".join(self.outdata), "".join(self.errdata)]