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?
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?
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.
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).
来源：https://stackoverflow.com/questions/28637795/debugging-a-python-application-that-just-sort-of-hangs