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] [3] and the "torrelque" python module of [2].
Features:
- Queue with repeats, delays and failed state
- Based on asyncio, aioredis
- Tested on Python 3.7
Install:
pip install arque
Usage:
import signal
import random
import logging
import asyncio
import aioredis
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(loop, redis=None):
redis = await aioredis.create_redis_pool(host, loop=loop, encoding=encoding)
try:
return await func(loop=loop, redis=redis)
finally:
redis.close()
await redis.wait_closed()
return wrapped
return wrapper
@aioredis_pool(host='redis://localhost', encoding='utf8')
async def produce_task(loop, redis=None):
logger.info('Starting producing...')
queue = Arque(redis=redis, loop=loop)
while True:
for _ in range(1):
task = {'value': random.randint(0, 99)}
logger.debug('Produced task %s', task)
await queue.enqueue(task, 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(loop, redis=None):
logger.info('Starting consuming...')
queue = Arque(redis=redis, loop=loop, 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}')
await asyncio.sleep(1)
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(loop, redis=None):
logger.info('Starting sweeping...')
queue = Arque(redis=redis, loop=loop, sweep_interval=5)
await queue.schedule_sweep()
@aioredis_pool(host='redis://localhost', encoding='utf8')
async def stats_task(loop, redis=None):
logger.info('Starting stats...')
queue = Arque(redis=redis, loop=loop)
while True:
stats = await queue.get_stats()
logger.info(stats)
await asyncio.sleep(5)
def create_tasks(loop):
tasks = []
for _ in range(5):
tasks.append(consume_task(loop))
tasks.append(produce_task(loop))
tasks.append(sweep_task(loop))
tasks.append(stats_task(loop))
return 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(asyncio.gather(*create_tasks(loop)))
finally:
loop.close()
logging.info("Successfully shutdown...")
Reference
[1] Reliable Queueing in Redis (Part 1)
[2] torrelque
[3] DEWIRE Redis as a Reliable Work Queue.pdf
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