Hi.
Trying to add task without running messaging backend (rabbitmq) should be
consistently throwing out errors.
Since it is not a django problem I suggest that you reach celery support
channels for better responses.
3.1.2018 11.26 "Mukul Mantosh" <mukulmantos...@gmail.com> kirjoitti:
> *I'm not sure about understanding you, where are you trying to call it
> again? from ipython?*
>
> I am calling from Django, the code is inside the view.
>
> *def test(request):*
> * try:*
> * add.delay(2, 2)*
> * except add.OperationalError as exc:*
> * print('error')*
> *return HttpResponse('working')*
>
> Point 1 - Stop RabbitMQ Server from terminal manually. (sudo service
> rabbitmq-server stop).
> Point 2 - Reload the view from the browser, it will immediately throw
> connection refused error which i could catch easily using try except block
> as provided in above example.
> Point 3 - If you try again reloading the page it hangs up over there. and
> it won't send any http response because it is still waiting and waiting to
> get response.
> Point 4 - You can see celery in background trying to reconnect to the
> broker every 5-10 seconds.
>
>
> *For what I understood, your problem is assuming that if a celery task
> fails, it won't be retried :)*
>
> It should be retried but i can't make a user wait for it because signup
> process is very quick and we cannot halt any user because our connection is
> lost. I just simply want if connection lost try for 10 seconds if connected
> its good otherwise just move on don't get stuck.
>
> Even if i tried add.apply_async((2, 2), retry=False) but it is still not
> working and the page is not giving back the HTTP Response.
>
> I think i have cleared everything what you wanted to know @Matemática A3K.
>
>
> On Wednesday, January 3, 2018 at 2:08:24 PM UTC+5:30, Matemática A3K wrote:
>>
>>
>>
>> On Tue, Jan 2, 2018 at 11:14 PM, Mukul Mantosh <mukulma...@gmail.com>
>> wrote:
>>
>>> I am not using result backend my question is that when the broker
>>> connection is lost it throws a connection refused exception which i could
>>> normally catch through the following given below code.
>>>
>>> *try:*
>>> * add.delay(2, 2)*
>>> *except add.OperationalError as exc:*
>>> * print('error');*
>>>
>>> Reference 1: http://docs.celeryproject.org/en/latest/userguide/calling
>>> .html#connection-error-handling
>>> Reference 2: https://github.com/celery/celery/issues/3933
>>>
>>>
>>> This try except block works only one time and next time when i try to
>>> call again add.delay(2,2)....the code is waiting to execute because celery
>>> is re-trying to establish the connection with the broker.
>>>
>>>
>> I'm not sure about understanding you, where are you trying to call it
>> again? from ipython?
>>
>>
>>> I just simply don't want to do, for example: There is a website where a
>>> user signup as a new user and we have to send an verification email through
>>> celery and suddenly the connection gets lost then the code will be in
>>> waiting state because celery is again retrying to establish a connection
>>> with the lost broker.
>>>
>>>
>> I agree that this may be better for a celery mailing list, as "low level"
>> celery is probably not the main expertise of most of the people reading
>> here, as Jason said, for what I understand http://docs.celeryproject.org/
>> en/latest/userguide/calling.html#calling-retry should be sufficient for
>> the "normal" cases.
>>
>> Have in mind that exception will be raised at the celery level, not
>> django because it's async, http://docs.celeryproject.org/
>> en/latest/userguide/calling.html#linking-callbacks-errbacks. Django
>> delegates the task to celery and celery takes care of executing it. If you
>> need to perfect warranty of execution, do it sync, inside the django view
>> send the verification mail, where you can show to the user that the
>> confirmation mail hasn't been sent.
>>
>>
>>> How can we solve this problem ?
>>>
>>>
>> For what I understood, your problem is assuming that if a celery task
>> fails, it won't be retried :)
>>
>>
>>>
>>>
>>> On Wednesday, January 3, 2018 at 12:45:10 AM UTC+5:30, Jason wrote:
>>>>
>>>> With a broker connection loss, the only thing that will happen is your
>>>> workers won't pick up new tasks.
>>>>
>>>> If you're posting to a result backend like redis and lose the
>>>> connection, then an exception will be raised in the logs and the task will
>>>> shut down.
>>>>
>>>> Remember tasks are independent processes and you can tell each worker
>>>> how many tasks to execute before its process is killed.
>>>>
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