[Answer]-Using topic exchange to send message from one method to another

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This is a good example for using Celery’s callback/linking function.

Celery supports linking tasks together so that one task follows another.
You can read more about it here

apply_async() functions has two optional arguments

+link : excute the linked function on success 
+link_error : excute the linked function on an error

@task
def add(a, b):
    return a + b

@task
def total(numbers):
    return sum(numbers)

@task
def error_handler(uuid):
    result = AsyncResult(uuid)
    exc = result.get(propagate=False)
    print('Task %r raised exception: %r\n%r' % (exc, result.traceback))

Now in your calling function do something like

def main():
    #for error_handling
    add.apply_async((2, 2), link_error=error_handler.subtask())

    #for linking 2 tasks
    add.apply_async((2, 2), link=add.subtask((8, )))
    # output 12

    #what you can do is your case is something like this. 
    if user_requires:
        add.apply_async((2, 2), link=add.subtask((8, )))
    else:
        add.apply_async((2, 2))

Hope this is helpful

👤Crazyshezy

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