huey · Python Simple Repository Browser

Project Links

Meta

Author: Charles Leifer

Classifiers

Development Status

5 - Production/Stable

Intended Audience

Developers

Programming Language

Python :: 3

Topic

Software Development :: Libraries :: Python Modules

a lightweight alternative.

huey is:

a task queue
written in python
clean and simple API

huey has:

support for redis (or valkey/redict), postgres, sqlite, file-system, or in-memory storage
zero dependencies (redis-py required to use redis-like brokers, psycopg for postgres).
example code.
django integration (native or via django.tasks) with admin integration for visibility and management.
documentation.

huey supports:

multi-process, multi-thread or greenlet task execution models
schedule tasks to execute at a given time, or after a given delay
schedule recurring tasks, like a crontab
automatically retry tasks that fail
task prioritization
task result storage
task expiration
task locking, rate-limits and timeouts
task pipelines and chains
groups (fan-out), chords (map / reduce)

At a glance

from huey import RedisHuey, crontab

# Or PostgresHuey, SqliteHuey, FileHuey, etc...
huey = RedisHuey('my-app', host='redis.myapp.com')

@huey.task()
def add_numbers(a, b):
    return a + b

@huey.task(retries=2, retry_delay=60)
def flaky_task(url):
    # This task might fail, in which case it will be retried up to 2 times
    # with a delay of 60s between retries.
    return this_might_fail(url)

@huey.periodic_task(crontab(minute='0', hour='3'))
def nightly_backup():
    sync_all_data()

Calling a task-decorated function will enqueue the function call for execution by the consumer. A special result handle is returned immediately, which can be used to fetch the result once the task is finished:

>>> from demo import add_numbers
>>> res = add_numbers(1, 2)
>>> res
<Result: task 6b6f36fc-da0d-4069-b46c-c0d4ccff1df6>

>>> res()
3

Tasks can be scheduled to run in the future:

>>> res = add_numbers.schedule((2, 3), delay=10)  # Will be run in ~10s.
>>> res(blocking=True)  # Will block until task finishes, in ~10s.
5

For much more, check out the guide or take a look at the example code.

Running the consumer

Run the consumer with four worker processes:

$ huey_consumer my_app.huey -k process -w 4

To run the consumer with a single worker thread (default):

$ huey_consumer my_app.huey

If your work-loads are mostly IO-bound, you can run the consumer with threads or greenlets instead. Because greenlets are so lightweight, you can run quite a few of them efficiently:

$ huey_consumer my_app.huey -k greenlet -w 32

Storage

Huey’s design and feature-set were informed by the capabilities of the Redis database. Redis is a fantastic fit for a lightweight task queueing library like Huey: it’s self-contained, versatile, and can be a multi-purpose solution for other web-application tasks like caching, event publishing, analytics, rate-limiting, and more.

Although Huey was designed with Redis in mind, the storage system implements a simple API and many other tools could be used instead of Redis if that’s your preference.

Huey comes with builtin support for Redis, Postgres, Sqlite, File-system, and in-memory storage.