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#!/usr/bin/env python3
import logging
import os
import signal
import time
import pykka
import pykka.debug
class DeadlockActorA(pykka.ThreadingActor):
def foo(self, b):
logging.debug("This is foo calling bar")
return b.bar().get()
class DeadlockActorB(pykka.ThreadingActor):
def __init__(self, a):
super().__init__()
self.a = a
def bar(self):
logging.debug("This is bar calling foo; BOOM!")
return self.a.foo().get()
if __name__ == "__main__":
print("Setting up logging to get output from signal handler...")
logging.basicConfig(level=logging.DEBUG)
print("Registering signal handler...")
signal.signal(signal.SIGUSR1, pykka.debug.log_thread_tracebacks)
print("Starting actors...")
a = DeadlockActorA.start().proxy()
b = DeadlockActorB.start(a).proxy()
print("Now doing something stupid that will deadlock the actors...")
a.foo(b)
time.sleep(0.01) # Yield to actors, so we get output in a readable order
pid = os.getpid()
print("Making main thread relax; not block, not quit")
print(f"1) Use `kill -SIGUSR1 {pid:d}` to log thread tracebacks")
print(f"2) Then `kill {pid:d}` to terminate the process")
while True:
time.sleep(1)
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