Provides job scheduling capabilities to RQ (Redis Queue)
Project description
RQ Scheduler
RQ Scheduler is a small package that adds job scheduling capabilities to RQ, a Redis based Python queuing library.
Requirements
Installation
You can install RQ Scheduler via pip:
pip install rq-scheduler
Or you can download the latest stable package from PyPI.
Usage
Schedule a job involves doing two different things: # Putting a job in the scheduler # Running a scheduler that will move scheduled jobs into queues when the time comes
Scheduling a Job
There are two ways you can schedule a job. The first is using RQ Scheduler’s enqueue_at:
from rq import use_connection from rq_scheduler import Scheduler from datetime import datetime use_connection() # Use RQ's default Redis connection scheduler = Scheduler() # Get a scheduler for the "default" queue # Puts a job into the scheduler. The API is similar to RQ except that it # takes a datetime object as first argument. So for example to schedule a # job to run on Jan 1st 2020 we do: scheduler.enqueue_at(datetime(2020, 1, 1), func) # Here's another example scheduling a job to run at a specific date and time, # complete with args and kwargs scheduler.enqueue_at(datetime(2020, 1, 1, 3, 4), func, foo, bar=baz)
The second way is using enqueue_in. Instead of taking a datetime object, this method expects a timedelta and schedules the job to run at X seconds/minutes/hours/days/weeks later. For example, if we want to monitor how popular a tweet is a few times during the course of the day, we could do something like:
from datetime import timedelta # Schedule a job to run 10 minutes, 1 hour and 1 day later scheduler.enqueue_in(timedelta(minutes=10), count_retweets, tweet_id) scheduler.enqueue_in(timedelta(hours=1), count_retweets, tweet_id) scheduler.enqueue_in(timedelta(days=1), count_retweets, tweet_id)
You can also explicitly pass in connection to use a different Redis server:
from redis import Redis from rq_scheduler import Scheduler from datetime import datetime scheduler = Scheduler('default', connection=Redis('192.168.1.3', port=123)) scheduler.enqueue_at(datetime(2020, 01, 01, 1, 1), func)
Periodic & Repeated Jobs
As of version 0.3, RQ Scheduler also supports creating periodic and repeated jobs. You can do this via the enqueue method. Note that this feature needs RQ >= 0.3.1.
This is how you do it:
scheduler.enqueue( scheduled_time=datetime.now(), # Time for first execution func=func, # Function to be queued args=[arg1, arg2], # Arguments passed into function when executed kwargs={'foo': 'bar'}, # Keyword arguments passed into function when executed interval=60, # Time before the function is called again, in seconds repeat=10 # Repeat this number of times (None means repeat forever) )
Canceling a job
To cancel a job, simply do:
scheduler.cancel(job)
Running the scheduler
RQ Scheduler comes with a script rqscheduler that runs a scheduler process that polls Redis once every minute and move scheduled jobs to the relevant queues when they need to be executed:
# This runs a scheduler process using the default Redis connection rqscheduler
If you want to use a different Redis server you could also do:
rqscheduler --host localhost --port 6379 --db 0
The script accepts these arguments:
-H or --host: Redis server to connect to
-p or --port: port to connect to
-d or --db: Redis db to use
-P or --password: password to connect to Redis
Changelog
Version 0.3.2:
Periodic jobs now require RQ >= 0.3.1
Version 0.3:
Added the capability to create periodic (cron) and repeated job using scheduler.enqueue
Project details
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