Celery API discovery module
Given the celery instance, it inspects all available celery workers to get the information about the queues they serve and tasks they know about.
Then it creates a chain of attributes allowing to execute any task as
queue_name.full_task_name.delay
.
With help of this class you can turn your Celery installation to a set of independent modules, each of which "exposes" its own "Celery API".
To make it more clear, the analogy with a random HTTP-based API available at http://example.com/users/get?email=john@example.com can be like:
- Celery object (including broker URL, result backend settings, etc) is the analogue of the protocol (http://)
- Queue name is the analogue of the hostname (example.com)
- Task name is the analogue of the URL path (/users/get)
- Task parameters the the analogue the querystring (?email=john@example.com)
Usage example.
If we have a Celery installation with two queues: "download" (knows how to execute "downloader.download_url" task) and "parse" (knows how to execute "parser.parse_html"), we can instantiate API and work with it the following way:
>>> api = celery_api.CeleryApi(celery)
>>> html_page = api.download.downloader.download_html.delay('http://example.com').get()
>>> html_tree = api.parse.parser.parse_html.delay(html_page).get()
Note
Ensure that workers are up and available from clients for inspection.
You may re-discover your installation after object creation by executing
api._discover()
.
Note
If you can't launch the task and get a NotRegistered exception instead,
it's most likely you have the CELERY_ALWAYS_EAGER
config option set to
True
.