Celery broadcast task not working - celery

Question

I've tried to make a broadcast task but only one of my workers recieve it per each call. Would you please help me? (I'm using rabbitmq and node-celery)
default_exchange = Exchange('celery', type='direct')
celery.conf.update(
CELERY_RESULT_BACKEND = "amqp",
CELERY_RESULT_SERIALIZER='json',
CELERY_QUEUES = (
Queue('celery', default_exchange, routing_key='celery'),
Broadcast('broadcast_tasks'),
),
CELERY_ROUTES = (
{'my_tasks.sample_broadcast_task': {
'queue': 'broadcast_tasks',
}},
{'my_tasks.sample_normal_task': {
'queue': 'celery',
'exchange': 'celery',
'exchange_type': 'direct',
'routing_key': 'celery',
}}
),
)
I've also test following configurtion but not working.
celery.conf.update(
CELERY_RESULT_BACKEND = "amqp",
CELERY_RESULT_SERIALIZER='json',
CELERY_QUEUES=(
Queue('celery', Exchange('celery'), routing_key='celery'),
Broadcast('broadcast'),
),
)
#celery.task(ignore_result=True, queue='broadcast',
options=dict(queue='broadcast'))
def sample_broadcast_task():
print "test"
EDIT
after changing how to run worker by adding -Q broadcast, now i face to this error:
PreconditionFailed: Exchange.declare: (406) PRECONDITION_FAILED - inequivalent arg 'type' for exchange 'broadcast' in vhost '/': received 'direct' but current is 'fanout'

Answer 1

After trying many many many things, i finally find a solution. This work for me.
( celery 3.1.24 (Cipater) and Python 2.7.12 )
WORKER - tasks.py :
from celery import Celery
import celery_config
from kombu.common import Broadcast, Queue, Exchange
app = Celery()
app.config_from_object(sysadmin_celery_config)
#app.task
def print_prout(x):
print x
return x
WORKER - celery_config.py :
# coding=utf-8
from kombu.common import Broadcast, Queue, Exchange
BROKER_URL = 'amqp://login:pass#172.17.0.1//'
CELERY_RESULT_BACKEND = 'redis://:login#172.17.0.1'
CELERY_TIMEZONE = 'Europe/Paris'
CELERY_ENABLE_UTC = True
CELERY_TASK_SERIALIZER = 'pickle'
CELERY_RESULT_SERIALIZER = 'pickle'
CELERY_ACCEPT_CONTENT = ['pickle', 'json', 'msgpack', 'yaml']
CELERY_DISABLE_RATE_LIMITS = True
CELERY_ALWAYS_EAGER = False
CELERY_QUEUES = (Broadcast('broadcast_tasks'), )
worker lauched with :
celery -A celery_worker.tasks worker --loglevel=info --concurrency=1 -n worker_name_1
On the client (another docker container for me).
from celery import Celery
from celery_worker import tasks
result = tasks.print_prout.apply_async(['prout'], queue='broadcast_tasks')
print result.get()
The next step for me is how to retrieve and display results returned by all the workers. The "print result.get()" seems to return only the result of the last worker.
It does not seem obvious ( Have Celery broadcast return results from all workers )

Answer 2

according to your description:
I've tried to make a broadcast task but only one of my workers recieve it per each call
you may be using direct type exchange.

Answer 3

Try this
from celery import Celery
from kombu.common import Broadcast
BROKER_URL = 'amqp://guest:guest#localhost:5672//'
class CeleryConf:
# List of modules to import when celery starts.
CELERY_ACCEPT_CONTENT = ['json']
CELERY_IMPORTS = ('main.tasks')
CELERY_QUEUES = (Broadcast('q1'),)
CELERY_ROUTES = {
'tasks.sampletask': {'queue': 'q1'}
}
celeryapp = Celery('celeryapp', broker=BROKER_URL)
celeryapp.config_from_object(CeleryConf())
#celeryapp.task
def sampletask(form):
print form
To send the message, do
d= sampletask.apply_async(['4c5b678350fc643'],serializer="json", queue='q1')