Skip to main content

Asyncio Reliable Queue (based on redis)

Project description

arque

Asyncio Reliable Queue (based on redis)

Inspired by Tom DeWire's article "Reliable Queueing in Redis (Part 1)" [1] [2] and the "torrelque" python module [3].

Features:

- Asynchronous: based on asyncio and aioredis
- Reliable: at any moment task data stored in redis database
- Throttling: controls number of tasks in execution
- Delayed queue: defers task availability
- Dead letters: put task data in failed queue after number of predefined retry attempts
- Tested on Python 3.7 and redis server '>=3.0.6', '<=5.0.5'
- Used in containerized applications (managed by kubernetes) in high load environments

Install:

pip install arque

Usage:

import signal
import random
import logging
import asyncio
import aioredis
import time
from functools import wraps
from arque import Arque

logger = logging.getLogger(__name__)


async def shutdown(signal, loop):
    """Cleanup tasks tied to the service's shutdown."""
    logging.info(f"Received exit signal {signal.name}...")
    tasks = [t for t in asyncio.all_tasks() if t is not asyncio.current_task()]
    [task.cancel() for task in tasks]
    logging.info(f"Cancelling {len(tasks)}outstanding tasks")
    await asyncio.gather(*tasks)
    logging.info(f"Flushing metrics")
    loop.stop()


def aioredis_pool(host='redis://localhost', encoding='utf8'):
    def wrapper(func):
        @wraps(func)
        async def wrapped():
            redis = await aioredis.create_redis_pool(host, encoding=encoding)
            try:
                return await func(redis=redis)
            finally:
                redis.close()
                await redis.wait_closed()

        return wrapped

    return wrapper


@aioredis_pool(host='redis://localhost', encoding='utf8')
async def produce_task(redis=None):
    logger.info('Starting producing...')
    queue = Arque(redis=redis)
    while True:
        for _ in range(1):
            task = {'value': random.randint(0, 99)}
            task_id = f"custom_{task['value']}_{time.time()}"
            logger.debug('Produced task %s', task)
            await queue.enqueue(task, task_id=task_id, task_timeout=10, delay=1)
        await asyncio.sleep(1)


async def process(task_data):
    logger.debug('Consumed task %s', task_data)
    await asyncio.sleep(1)


@aioredis_pool(host='redis://localhost', encoding='utf8')
async def consume_task(redis=None):
    logger.info('Starting consuming...')
    queue = Arque(redis=redis, working_limit=3)
    while True:
        task_id, task_data = await queue.dequeue()
        if task_id == '__not_found__':
            continue

        if task_id == '__overloaded__':
            print(f'TASK ID: {task_id}')
            await asyncio.sleep(1)
            continue

        if task_id == '__marked_as_failed___':
            print(f'FAILED  ID: {task_id}')
            continue

        try:
            await process(task_data)
            await queue.release(task_id)
        except Exception:
            logger.exception('Job processing has failed')
            await queue.requeue(task_id, delay=5)
            stats = await queue.get_stats()
            logger.info(stats)


@aioredis_pool(host='redis://localhost', encoding='utf8')
async def sweep_task(redis=None):
    logger.info('Starting sweeping...')
    queue = Arque(redis=redis, sweep_interval=5)
    await queue.schedule_sweep()


@aioredis_pool(host='redis://localhost', encoding='utf8')
async def stats_task(redis=None):
    logger.info('Starting stats...')
    queue = Arque(redis=redis)
    while True:
        stats = await queue.get_stats()
        logger.info(stats)
        await asyncio.sleep(5)


async def example():
    tasks = []
    for _ in range(5):
        tasks.append(consume_task())
    tasks.append(produce_task())
    tasks.append(sweep_task())
    tasks.append(stats_task())
    await asyncio.gather(*tasks)


if __name__ == '__main__':
    logging.basicConfig(level=logging.DEBUG, format='%(asctime)s %(message)s')
    loop = asyncio.get_event_loop()
    signals = (signal.SIGHUP, signal.SIGTERM, signal.SIGINT, signal.SIGUSR1)
    for s in signals:
        loop.add_signal_handler(s, lambda s=s: asyncio.create_task(shutdown(s, loop)))
    try:
        loop.run_until_complete(example())
    finally:
        loop.close()
        logging.info("Successfully shutdown...")

Reference

[1] Reliable Queueing in Redis (Part 1)
[2] DEWIRE Redis as a Reliable Work Queue.pdf
[3] torrelque

Project details


Download files

Download the file for your platform. If you're not sure which to choose, learn more about installing packages.

Source Distribution

arque-1.1.0.tar.gz (6.8 kB view hashes)

Uploaded source

Built Distribution

arque-1.1.0-py3-none-any.whl (7.5 kB view hashes)

Uploaded py3

Supported by

AWS AWS Cloud computing Datadog Datadog Monitoring Facebook / Instagram Facebook / Instagram PSF Sponsor Fastly Fastly CDN Google Google Object Storage and Download Analytics Huawei Huawei PSF Sponsor Microsoft Microsoft PSF Sponsor NVIDIA NVIDIA PSF Sponsor Pingdom Pingdom Monitoring Salesforce Salesforce PSF Sponsor Sentry Sentry Error logging StatusPage StatusPage Status page