Celery error : result.get times out

Question

I've installed Celery and I'm trying to test it with the Celery First Steps Doc.

I tried using both Redis and RabbitMQ as brokers and backends, but I can't get the result with :

result.get(timeout = 10)

Each time, I get this error :

  Traceback (most recent call last):
  File "<input>", line 11, in <module>
  File "/home/mehdi/.virtualenvs/python3/lib/python3.4/site-packages/celery/result.py", line 169, in get
    no_ack=no_ack,
  File "/home/mehdi/.virtualenvs/python3/lib/python3.4/site-packages/celery/backends/base.py", line 225, in wait_for
    raise TimeoutError('The operation timed out.')
celery.exceptions.TimeoutError: The operation timed out.

The broker part seems to work just fine : when I run this code

from celery import Celery

app = Celery('tasks', backend='redis://localhost/', broker='amqp://')

@app.task
def add(x, y):
    return x + y

result = add.delay(4,4)

I get (as expected)

[2015-08-04 12:05:44,910: INFO/MainProcess] Received task: tasks.add[741160b8-cb7b-4e63-93c3-f5e43f8f8a02]

[2015-08-04 12:05:44,911: INFO/MainProcess] Task tasks.add[741160b8-cb7b-4e63-93c3-f5e43f8f8a02] succeeded in 0.0004287530000510742s: 8

P.S : I'm using Xubuntu 64bit

EDIT :

My app.conf

{'CELERY_RESULT_DB_TABLENAMES': None, 
'BROKER_TRANSPORT_OPTIONS': {}, 
'BROKER_USE_SSL': False, 
'CELERY_BROADCAST_QUEUE': 'celeryctl', 
'EMAIL_USE_TLS': False, 
'CELERY_STORE_ERRORS_EVEN_IF_IGNORED': False, 
'CELERY_CREATE_MISSING_QUEUES': True, 
'CELERY_DEFAULT_QUEUE': 'celery', 
'CELERY_SEND_TASK_SENT_EVENT': False, 
'CELERYD_TASK_TIME_LIMIT': None, 
'BROKER_URL': 'amqp://', 
'CELERY_EVENT_QUEUE_EXPIRES': None, 
'CELERY_DEFAULT_EXCHANGE_TYPE': 'direct', 
'CELERYBEAT_SCHEDULER': 'celery.beat:PersistentScheduler', 
'CELERY_MAX_CACHED_RESULTS': 100, 
'CELERY_RESULT_PERSISTENT': None, 
'CELERYD_POOL': 'prefork', 
'CELERYD_AGENT': None, 
'EMAIL_HOST': 'localhost', 
'CELERY_CACHE_BACKEND_OPTIONS': {}, 
'BROKER_HEARTBEAT': None, 
'CELERY_RESULT_ENGINE_OPTIONS': None, 
'CELERY_RESULT_SERIALIZER': 'pickle', 
'CELERYBEAT_SCHEDULE_FILENAME': 'celerybeat-schedule', 
'CELERY_REDIRECT_STDOUTS_LEVEL': 'WARNING', 
'CELERY_IMPORTS': (), 
'SERVER_EMAIL': 'celery@localhost', 
'CELERYD_TASK_LOG_FORMAT': '[%(asctime)s: %(levelname)s/%(processName)s] %(task_name)s[%(task_id)s]: %(message)s', 
'CELERY_SECURITY_CERTIFICATE': None, 
'CELERYD_LOG_COLOR': None, 
'CELERY_RESULT_EXCHANGE': 'celeryresults', 
'CELERY_TRACK_STARTED': False, 
'CELERY_REDIS_PASSWORD': None, 
'BROKER_USER': None, 
'CELERY_COUCHBASE_BACKEND_SETTINGS': None, 
'CELERY_RESULT_EXCHANGE_TYPE': 'direct', 
'CELERY_REDIS_DB': None, 
'CELERYD_TIMER_PRECISION': 1.0, 
'CELERY_REDIS_PORT': None, 
'BROKER_TRANSPORT': None, 
'CELERYMON_LOG_FILE': None, 
'CELERYD_CONCURRENCY': 0, 
'CELERYD_HIJACK_ROOT_LOGGER': True, 
'BROKER_VHOST': None, 
'CELERY_DEFAULT_EXCHANGE': 'celery', 
'CELERY_DEFAULT_ROUTING_KEY': 'celery', 
'CELERY_ALWAYS_EAGER': False, 
'EMAIL_TIMEOUT': 2, 
'CELERYD_TASK_SOFT_TIME_LIMIT': None, 
'CELERY_WORKER_DIRECT': False, 
'CELERY_REDIS_HOST': None, 
'CELERY_QUEUE_HA_POLICY': None, 
'BROKER_PORT': None, 
'CELERYD_AUTORELOADER': 'celery.worker.autoreload:Autoreloader', 
'BROKER_CONNECTION_TIMEOUT': 4, 
'CELERY_ENABLE_REMOTE_CONTROL': True, 
'CELERY_RESULT_DB_SHORT_LIVED_SESSIONS': False, 
'CELERY_EVENT_SERIALIZER': 'json', 
'CASSANDRA_DETAILED_MODE': False, 
'CELERY_REDIS_MAX_CONNECTIONS': None, 
'CELERY_CACHE_BACKEND': None, 
'CELERYD_PREFETCH_MULTIPLIER': 4, 
'BROKER_PASSWORD': None, 
'CELERY_BROADCAST_EXCHANGE_TYPE': 'fanout', 
'CELERY_EAGER_PROPAGATES_EXCEPTIONS': False, 
'CELERY_IGNORE_RESULT': False, 
'CASSANDRA_KEYSPACE': None, 
'EMAIL_HOST_PASSWORD': None, 
'CELERYMON_LOG_LEVEL': 'INFO', 
'CELERY_DISABLE_RATE_LIMITS': False, 
'CELERY_TASK_PUBLISH_RETRY_POLICY': {'interval_start': 0, 
'interval_max': 1, 
'max_retries': 3, 
'interval_step': 0.2}, 
'CELERY_SECURITY_KEY': None, 
'CELERY_MONGODB_BACKEND_SETTINGS': None, 
'CELERY_DEFAULT_RATE_LIMIT': None, 
'CELERYBEAT_SYNC_EVERY': 0, 
'CELERY_EVENT_QUEUE_TTL': None, 
'CELERYD_POOL_PUTLOCKS': True, 
'CELERY_TASK_SERIALIZER': 'pickle', 
'CELERYD_WORKER_LOST_WAIT': 10.0, 
'CASSANDRA_SERVERS': None, 
'CELERYD_POOL_RESTARTS': False, 
'CELERY_TASK_PUBLISH_RETRY': True, 
'CELERY_ENABLE_UTC': True, 
'CELERY_SEND_EVENTS': False, 
'BROKER_CONNECTION_MAX_RETRIES': 100, 
'CELERYD_LOG_FILE': None, 
'CELERYD_FORCE_EXECV': False, 
'CELERY_CHORD_PROPAGATES': True, 
'CELERYD_AUTOSCALER': 'celery.worker.autoscale:Autoscaler', 
'CELERYD_STATE_DB': None, 
'CELERY_ROUTES': None, 
'CELERYD_TIMER': None, 
'ADMINS': (), 
'BROKER_HEARTBEAT_CHECKRATE': 3.0, 
'CELERY_ACCEPT_CONTENT': ['json', 
'pickle', 
'msgpack', 
'yaml'], 
'BROKER_LOGIN_METHOD': None, 
'BROKER_CONNECTION_RETRY': True, 
'CELERY_TIMEZONE': None, 
'CASSANDRA_WRITE_CONSISTENCY': None, 
'CELERYBEAT_MAX_LOOP_INTERVAL': 0, 
'CELERYD_LOG_LEVEL': 'WARN', 
'CELERY_REDIRECT_STDOUTS': True, 
'BROKER_POOL_LIMIT': 10, 
'CELERY_SECURITY_CERT_STORE': None, 
'CELERYD_CONSUMER': 'celery.worker.consumer:Consumer', 
'CELERY_INCLUDE': (), 
'CELERYD_MAX_TASKS_PER_CHILD': None, 
'CELERYD_LOG_FORMAT': '[%(asctime)s: %(levelname)s/%(processName)s] %(message)s', 
'CELERY_ANNOTATIONS': None, 
'CELERY_MESSAGE_COMPRESSION': None, 
'CASSANDRA_READ_CONSISTENCY': None, 
'EMAIL_USE_SSL': False, 
'CELERY_SEND_TASK_ERROR_EMAILS': False, 
'CELERY_QUEUES': None, 
'CELERY_ACKS_LATE': False, 
'CELERYMON_LOG_FORMAT': '[%(asctime)s: %(levelname)s] %(message)s', 
'CELERY_TASK_RESULT_EXPIRES': datetime.timedelta(1), 
'BROKER_HOST': None, 
'EMAIL_PORT': 25, 
'BROKER_FAILOVER_STRATEGY': None, 
'CELERY_RESULT_BACKEND': 'rpc://', 
'CELERY_BROADCAST_EXCHANGE': 'celeryctl', 
'CELERYBEAT_LOG_FILE': None, 
'CELERYBEAT_SCHEDULE': {}, 
'CELERY_RESULT_DBURI': None, 
'CELERY_DEFAULT_DELIVERY_MODE': 2, 
'CELERYBEAT_LOG_LEVEL': 'INFO', 
'CASSANDRA_COLUMN_FAMILY': None, 
'EMAIL_HOST_USER': None}

Answer 1

Finally worked with this project layout

proj/celery_proj/__init__.py
                /celery.py
                /tasks.py
    /test.py

Where

celery.py

from __future__ import absolute_import

from celery import Celery

app = Celery('celery_proj',
             broker='amqp://',
             backend='amqp://',
             include=['celery_proj.tasks'])

# Optional configuration, see the application user guide.
app.conf.update(
    CELERY_TASK_RESULT_EXPIRES=3600,
)

if __name__ == '__main__':
    app.start()

tasks.py

from __future__ import absolute_import

from celery_proj.celery import app


@app.task
def add(x, y):
    return x + y


@app.task
def mul(x, y):
    return x * y


@app.task
def xsum(numbers):
    return sum(numbers)

test.py

__author__ = 'mehdi'
path = '/home/mehdi/PycharmProjects'
import sys
sys.path.append(path)
from celery_proj.tasks import add

r = add.delay(4,4)
print(r.status)
print(r.result)

And launching the worker with :

cd proj
celery -A celery_proj worker -l info

An then running test.py :

python test.py

Answer 2

Using app.backend.get_result(result.id) to instead of AsyncResult.get() since AsyncResult.get() will block until the task status become ready, however the task has already run completed

Answer 3

The 'backend' configuration can no longer be passed to the Celery object as an optional parameter, but should be passed through the python configuration parameter CELERY_RESULT_BACKEND (see https://github.com/celery/celery/issues/2146).

So the tasks.py (from the Celery tutorial) should look something like:

from celery import Celery

app = Celery('tasks', broker='amqp://guest@localhost//')
app.config_from_object('celeryconfig')

@app.task
def add(x, y):
    print '[' + str(x) + '][' + str(y) + ']=' + str(x+y)
    return x + y

Create a file celeryconfig.py in the same directory as tasks.py with the following content:

CELERY_RESULT_BACKEND='amqp://'

Answer 4

After modifying of tasks it is necessary to restart celery to reread changes.