zulip/zerver/management/commands/process_queue.py

import logging
import signal
import sys
import threading
from argparse import ArgumentParser
from types import FrameType
from typing import Any, List

from django.conf import settings
from django.core.management.base import BaseCommand, CommandError
from django.utils import autoreload

from zerver.worker.queue_processors import get_active_worker_queues, get_worker


class Command(BaseCommand):
    def add_arguments(self, parser: ArgumentParser) -> None:
        parser.add_argument('--queue_name', metavar='<queue name>', type=str,
                            help="queue to process")
        parser.add_argument('--worker_num', metavar='<worker number>', type=int, nargs='?', default=0,
                            help="worker label")
        parser.add_argument('--all', dest="all", action="store_true", default=False,
                            help="run all queues")
        parser.add_argument('--multi_threaded', nargs='+',
                            metavar='<list of queue name>',
                            type=str, required=False,
                            help="list of queue to process")

    help = "Runs a queue processing worker"

    def handle(self, *args: Any, **options: Any) -> None:
        logging.basicConfig()
        logger = logging.getLogger('process_queue')

        def exit_with_three(signal: int, frame: FrameType) -> None:
            """
            This process is watched by Django's autoreload, so exiting
            with status code 3 will cause this process to restart.
            """
            logger.warning("SIGUSR1 received. Restarting this queue processor.")
            sys.exit(3)

        if not settings.USING_RABBITMQ:
            # Make the warning silent when running the tests
            if settings.TEST_SUITE:
                logger.info("Not using RabbitMQ queue workers in the test suite.")
            else:
                logger.error("Cannot run a queue processor when USING_RABBITMQ is False!")
            raise CommandError

        def run_threaded_workers(queues: List[str], logger: logging.Logger) -> None:
            cnt = 0
            for queue_name in queues:
                if not settings.DEVELOPMENT:
                    logger.info('launching queue worker thread ' + queue_name)
                cnt += 1
                td = Threaded_worker(queue_name)
                td.start()
            assert len(queues) == cnt
            logger.info('%d queue worker threads were launched', cnt)

        if options['all']:
            signal.signal(signal.SIGUSR1, exit_with_three)
            autoreload.run_with_reloader(run_threaded_workers, get_active_worker_queues(), logger)
        elif options['multi_threaded']:
            signal.signal(signal.SIGUSR1, exit_with_three)
            queues = options['multi_threaded']
            autoreload.run_with_reloader(run_threaded_workers, queues, logger)
        else:
            queue_name = options['queue_name']
            worker_num = options['worker_num']

            logger.info("Worker %d connecting to queue %s", worker_num, queue_name)
            worker = get_worker(queue_name)
            worker.setup()

            def signal_handler(signal: int, frame: FrameType) -> None:
                logger.info("Worker %d disconnecting from queue %s", worker_num, queue_name)
                worker.stop()
                sys.exit(0)
            signal.signal(signal.SIGTERM, signal_handler)
            signal.signal(signal.SIGINT, signal_handler)
            signal.signal(signal.SIGUSR1, signal_handler)

            worker.start()

class Threaded_worker(threading.Thread):
    def __init__(self, queue_name: str) -> None:
        threading.Thread.__init__(self)
        self.worker = get_worker(queue_name)

    def run(self) -> None:
        self.worker.setup()
        logging.debug('starting consuming ' + self.worker.queue_name)
        self.worker.start()