调试只是“挂起”的python应用程序。 [英] Debugging a python application that just sort of "hangs"

问题描述

我有一个用python编写的事件驱动应用程序。一段时间后（通常> 1周），它似乎只是停止响应事件。当发生这种情况时，我只需按ctrl-C并重新运行，一切都很好。但是，这种情况一直很烦人，我不知道是什么原因造成的。 有没有一种方法可以运行我的应用程序，当这种情况发生并且应用程序不再接受连接时，我可以进入调试器，查看其运行情况以及为什么不建立连接？

I have an event-driven application, written in python. After a while (usually >1 week) it appears to just stop responding to events. When this happens, I just ctrl-C and re-run and all is well-again. However, it's kind of annoying that this keeps happening and I have no idea what's causing it. Is there a way I can run my application that when this occurs and the application is no longer accepting connections, I can drop into a debugger and see what it's doing and why it's not taking connections?

我以前使用过pdb，但是我使用过它的方式（

，如果条件：pdb.set_trace（））并不是真正适用于此，因为我不知道它失败时在代码中的作用。我的理想情况是使用Ctrl-somethingelse代替Ctrl-C，这会使它停止并进入调试器。这样的事情容易做到吗？

I've used pdb before, but the way I've used it (if condition: pdb.set_trace()) doesn't really apply here, because I have no idea what it's doing in the code when it fails. My ideal situation would be instead of Ctrl-C maybe I hit Ctrl-somethingelse and that causes it to stop and drop into the debugger. Is such a thing easily done?

推荐答案

在您的情况下触发pdb可能并不简单。但是，每当需要调试此类挂起时，我都会使用 <$来检查进程中所有线程的回溯快照。 c $ c> dumpstacks（） 函数。

Triggering pdb in your case is probably not simple. However, whenever I need to debug such hangs, I inspect a "snapshot" of tracebacks of all the threads in the process, using the dumpstacks() function.

您可以使用计时器定期调用它，并将输出打印到一个日志文件，并在发现挂起时引用它，或者利用某些RPC机制（例如信号）来按需触发进程中的函数调用。我通常这样做，因为我系统中的进程已经在侦听此类RPC请求（使用rpyc）。

You can either use a timer to call it periodically and print the output to a log file, and refer to it when you notice the hanging, or harness some RPC mechanism (e.g. signals) to trigger the function call in your process on demand. I usually do the latter, because the processes in my system already listen to such RPC requests (using rpyc).

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