tasks.rst

Tasks

Async

Use async from your code to quickly offload tasks to the cluster:

from django_q import async, result

# create the task
async('math.copysign', 2, -2)

# or with import and storing the id
import math.copysign

task_id = async(copysign, 2, -2)

# get the result
task_result = result(task_id)

# result returns None if the task has not been executed yet
# so in most cases you will want to use a hook:

async('math.modf', 2.5, hook='hooks.print_result')

# hooks.py
def print_result(task):
    print(task.result)

Synchronous testing

async can be instructed to execute a task immediately by setting the optional keyword sync=True. The task will then be injected straight into a worker and the result saved by a monitor instance:

from django_q import async, fetch

# create a synchronous task
task_id = async('my.buggy.code', sync=True)

# the task will then be available immediately
task = fetch(task_id)

# and can be examined
if not task.success:
    print('An error occurred: {}'.format(task.result))

An error occurred: ImportError("No module named 'my'",)

Note that async will block until the task is executed and saved. This feature bypasses the Redis server and is intended for debugging and development.

Connection pooling

Django Q tries to pass redis connections around its parts as much as possible to save you from running out of connections. When you are making individual calls to async a lot though, it can help to set up a redis connection to pass to async:

# redis connection economy example
from django_q import async
from django_q.conf import redis_client

for i in range(50):
    async('math.modf', 2.5, redis=redis_client)

Tip

If you are using django-redis , you can configure <django_redis> Django Q to use its connection pool.

Reference

param func

The task function to execute

param args

The arguments for the task function

type func

str or object

param hook

Optional function to call after execution

type hook

str or object

param bool sync

If set to True, async will simulate a task execution

param redis

Optional redis connection

param kwargs

Keyword arguments for the task function

returns

The uuid of the task

rtype

str