Celery - Get task id for current task

Question

How can I get the task_id value for a task from within the task? Here's my code:

from celery.decorators import task
from django.core.cache import cache

@task
def do_job(path):
    "Performs an operation on a file"

    # ... Code to perform the operation ...

    cache.set(current_task_id, operation_results)

The idea is that when I create a new instance of the task, I retrieve the task_id from the task object. I then use the task id to determine whether the task has completed. I don't want to keep track of the task by the path value because the file is "cleaned up" after the task completes, and may or may not exist.

In the above example, how would I get the value of current_task_id?

Answer 1

Since Celery 2.2.0, information related to the currently executed task is saved to task.request (it's called «the context»). So you should get task id from this context (not from keyword arguments, which are deprecated):

@task
def do_job(path):
    cache.set(do_job.request.id, operation_results)

The list of all available fields is documented here: http://celery.readthedocs.org/en/latest/userguide/tasks.html?highlight=requestcontext#context

Answer 2

Celery does set some default keyword arguments if the task accepts them. (you can accept them by either using **kwargs, or list them specifically)

@task
def do_job(path, task_id=None):
    cache.set(task_id, operation_results)

The list of default keyword arguments is documented here: http://ask.github.com/celery/userguide/tasks.html#default-keyword-arguments

Answer 3

As of celery 3.1, you can use the bind decorator argument, and have access to the current request:

@task(bind=True)
def do_job(self, path):
    cache.set(self.request.id, operation_results)