Question

我正在尝试调试使用pynetdicom库的应用程序。我不确定具体细节是多么相关，但是相关的是它大量使用多线程来运行后台套接字监听器任务而不阻塞主线程。 storescp.py示例可用于重现此内容。

每当我放置一个遇到的断点（无论遇到什么线程，主要或子进程），我都会得到以下回溯：

Traceback (most recent call last):
  File "/Applications/Aptana Studio 3/plugins/org.python.pydev_2.7.0.2013012902/pysrc/pydevd.py", line 1397, in <module>
    debugger.run(setup['file'], None, None)
  File "/Applications/Aptana Studio 3/plugins/org.python.pydev_2.7.0.2013012902/pysrc/pydevd.py", line 1090, in run
    pydev_imports.execfile(file, globals, locals) #execute the script
  File "/Users/alexw/Development/Python/kreport2/KReport2/dicomdatascraper.py", line 183, in <module>
    oldDicomList = copy.copy(newData)
  File "/Users/alexw/Development/Python/kreport2/KReport2/dicomdatascraper.py", line 183, in <module>
    oldDicomList = copy.copy(newData)
  File "/Applications/Aptana Studio 3/plugins/org.python.pydev_2.7.0.2013012902/pysrc/pydevd_frame.py", line 135, in trace_dispatch
    self.doWaitSuspend(thread, frame, event, arg)
  File "/Applications/Aptana Studio 3/plugins/org.python.pydev_2.7.0.2013012902/pysrc/pydevd_frame.py", line 25, in doWaitSuspend
    self._args[0].doWaitSuspend(*args, **kwargs)
  File "/Applications/Aptana Studio 3/plugins/org.python.pydev_2.7.0.2013012902/pysrc/pydevd.py", line 832, in doWaitSuspend
    self.processInternalCommands()
  File "/Applications/Aptana Studio 3/plugins/org.python.pydev_2.7.0.2013012902/pysrc/pydevd.py", line 360, in processInternalCommands
    thread_id = GetThreadId(t)
  File "/Applications/Aptana Studio 3/plugins/org.python.pydev_2.7.0.2013012902/pysrc/pydevd_constants.py", line 140, in GetThreadId
    return thread.__pydevd_id__
  File "/Users/alexw/.virtualenvs/kreport2dev/devlibs/pynetdicom/source/netdicom/applicationentity.py", line 73, in __getattr__
    obj = eval(attr)()
  File "<string>", line 1, in <module>
NameError: name '__pydevd_id__' is not defined

我的想法是，或许，为了使事情有效，PyDev会将__pydevd_id__修补为生成的线程，但无法将这些线程修补到这些线程，因为它们是，实际上，子类而不是threading.Thread的直接实例（在这种情况下，worker是class Association(threading.Thread):的实例）。

当然，我不太了解PyDev以证实这个理论，或者解决它。互联网似乎也没有。

子类化Thread是否很少使用在PyDev架构中根本不考虑的模式？如果不重新设计库，那么如何解决这个问题呢？

Answer 1

我只需要更加努力地回顾那个追溯。

pynetdicom库在其threading.Thread的子类中，覆盖__getattr__并且有点破坏了它。问题是：

def __getattr__(self, attr):
    #while not self.AssociationEstablished:
    #    time.sleep(0.001)
    obj = eval(attr)

    # do some stuff

    return obj

当传递不存在的属性时，会引发NameError。这不是由pydev的monkeypatching例程（if thread.__pydevd_id__ raises AttributeError, thread.__pydevd_id__ = stuff）

捕获的

解决方案是如此更新该部分：

def __getattr__(self, attr):
    #while not self.AssociationEstablished:
    #    time.sleep(0.001)
    try:
        obj = eval(attr)
    except NameError:
        raise AttributeError

    # do some stuff

    return obj

这会拦截NameError并引发AttributeError，如果查询的属性不存在则应该__getattr__。

pydev多线程调试

1 个答案: