logrotate (USR1 signal) restarts uvicorn worker

[wonjoonSeol-WS]

I use FastAPI+Uvicorn+Gunicorn and issuing USR1 signal to uvicorn worker restarts the worker.

I believe the issue is to do with uvicorn worker not implementing signal handler - github.com/encode/uvicorn/blob/….

    def init_signals(self) -> None:
        # Reset signals so Gunicorn doesn't swallow subprocess return codes
        # other signals are set up by Server.install_signal_handlers()
        # See: https://github.com/encode/uvicorn/issues/894
        for s in self.SIGNALS:
            signal.signal(s, signal.SIG_DFL)

It converts it to signal.SIG_DFL.

SIGUSR1 and SIGUSR2 both have the default action Term -- the process is terminated. (unix.stackexchange.com/questions/38589/…)

According to a similar issue page, #896 (comment)
yinkh changed init_signals to gunicorn worker's original and this change no longer restarts the worker.

I also notice that Uvicorn only handles two signals:

HANDLED_SIGNALS = (
    signal.SIGINT,  # Unix signal 2. Sent by Ctrl+C.
    signal.SIGTERM,  # Unix signal 15. Sent by `kill <pid>`.
)

I would be more than happy to contribute to uvicorn, if I could change the worker init_signals function to do the same with gunicorn worker?

    def init_signals(self):
        # reset signaling
        for s in self.SIGNALS:
            signal.signal(s, signal.SIG_DFL)
        # init new signaling
        signal.signal(signal.SIGQUIT, self.handle_quit)
        signal.signal(signal.SIGTERM, self.handle_exit)
        signal.signal(signal.SIGINT, self.handle_quit)
        signal.signal(signal.SIGWINCH, self.handle_winch)
        signal.signal(signal.SIGUSR1, self.handle_usr1)
        signal.signal(signal.SIGABRT, self.handle_abort)

        # Don't let SIGTERM and SIGUSR1 disturb active requests
        # by interrupting system calls
        signal.siginterrupt(signal.SIGTERM, False)
        signal.siginterrupt(signal.SIGUSR1, False)

        if hasattr(signal, 'set_wakeup_fd'):
            signal.set_wakeup_fd(self.PIPE[1])

[euri10]

seems legit issue to me, coming from https://stackoverflow.com/questions/72891901/gunicorn-worker-terminated-due-to-signal-10
I guess the #895 was a little bit too much on resetting signal for that usecase
PR welcomed

[wonjoonSeol-WS]

Added steps to reproduce and a potential solution here:
#1559 (comment)