Kombu 4.1 seems to break celery's task_publish_retry

Dear valued Kombu developers,

when using Celery with RabbitMQ I stumbled across a problem where celery’s task_publish_retry gets not honored, when I use Kombu 4.1.0. Please see below my Bug report. If you have any further questions, please let me know.

Many thanks in advance. Best Regards, Stephan

Environment:

• Debian 8.9 with python 3.4.2
• amqp==2.2.1
• billiard==3.5.0.3
• celery==4.1.0
• kombu==4.1.0
• pytz==2017.2
• vine==1.1.4

Steps to reproduce:

1. Make sure Broker is NOT running
2. Create tasks.py

from celery import Celery
app = Celery('tasks', broker='pyamqp://celery:secret@localhost/myvhost')
@app.task
def add(x, y):
    return x + y

1. Create test.py

from tasks import add
add.apply_async((4,4), retry=False)

1. Run test.py

• Expected result: kombu.exceptions.OperationalError raised because connection to broker cannot be established
• Observed result: test.py blocks/hangs.

1. Hit CTRL-C to get the stack trace Traceback (most recent call last): File “/home/a2822bp/.virtualenvs/dssweb/lib/python3.4/site-packages/kombu/utils/functional.py”, line 36, in call return self.value AttributeError: ‘ChannelPromise’ object has no attribute ‘value’

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/home/a2822bp/.virtualenvs/dssweb/lib/python3.4/site-packages/kombu/utils/functional.py", line 333, in retry_over_time
    return fun(*args, **kwargs)
  File "/home/a2822bp/.virtualenvs/dssweb/lib/python3.4/site-packages/kombu/connection.py", line 261, in connect
    return self.connection
  File "/home/a2822bp/.virtualenvs/dssweb/lib/python3.4/site-packages/kombu/connection.py", line 802, in connection
    self._connection = self._establish_connection()
  File "/home/a2822bp/.virtualenvs/dssweb/lib/python3.4/site-packages/kombu/connection.py", line 757, in _establish_connection
    conn = self.transport.establish_connection()
  File "/home/a2822bp/.virtualenvs/dssweb/lib/python3.4/site-packages/kombu/transport/pyamqp.py", line 130, in establish_connection
    conn.connect()
  File "/home/a2822bp/.virtualenvs/dssweb/lib/python3.4/site-packages/amqp/connection.py", line 296, in connect
    self.transport.connect()
  File "/home/a2822bp/.virtualenvs/dssweb/lib/python3.4/site-packages/amqp/transport.py", line 123, in connect
    self._connect(self.host, self.port, self.connect_timeout)
  File "/home/a2822bp/.virtualenvs/dssweb/lib/python3.4/site-packages/amqp/transport.py", line 164, in _connect
    self.sock.connect(sa)
ConnectionRefusedError: [Errno 111] Connection refused

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "test.py", line 2, in <module>
    add.apply_async((4,4), retry=False)
  File "/home/a2822bp/.virtualenvs/dssweb/lib/python3.4/site-packages/celery/app/task.py", line 536, in apply_async
    **options
  File "/home/a2822bp/.virtualenvs/dssweb/lib/python3.4/site-packages/celery/app/base.py", line 737, in send_task
    amqp.send_task_message(P, name, message, **options)
  File "/home/a2822bp/.virtualenvs/dssweb/lib/python3.4/site-packages/celery/app/amqp.py", line 554, in send_task_message
    **properties
  File "/home/a2822bp/.virtualenvs/dssweb/lib/python3.4/site-packages/kombu/messaging.py", line 181, in publish
    exchange_name, declare,
  File "/home/a2822bp/.virtualenvs/dssweb/lib/python3.4/site-packages/kombu/messaging.py", line 187, in _publish
    channel = self.channel
  File "/home/a2822bp/.virtualenvs/dssweb/lib/python3.4/site-packages/kombu/messaging.py", line 209, in _get_channel
    channel = self._channel = channel()
  File "/home/a2822bp/.virtualenvs/dssweb/lib/python3.4/site-packages/kombu/utils/functional.py", line 38, in __call__
    value = self.__value__ = self.__contract__()
  File "/home/a2822bp/.virtualenvs/dssweb/lib/python3.4/site-packages/kombu/messaging.py", line 224, in <lambda>
    channel = ChannelPromise(lambda: connection.default_channel)
  File "/home/a2822bp/.virtualenvs/dssweb/lib/python3.4/site-packages/kombu/connection.py", line 819, in default_channel
    self.ensure_connection()
  File "/home/a2822bp/.virtualenvs/dssweb/lib/python3.4/site-packages/kombu/connection.py", line 405, in ensure_connection
    callback)
  File "/home/a2822bp/.virtualenvs/dssweb/lib/python3.4/site-packages/kombu/utils/functional.py", line 345, in retry_over_time
    sleep(1.0)
KeyboardInterrupt

1. Install Kombu 4.0.2 using pip install --upgrade kombu==4.0.2

2. Rerun test.py

• Exception is raised as expected:

kombu.exceptions.OperationalError: [Errno 111] Connection refused

[iamunadike]

This useless issue has not been fixed yet its a shame and annoying I am running django pytest with rabbitmq and celery. When I run the pytest without starting the server I get the same issue kombu.exceptions.OperationalError: [Errno 111] Connection refused

Need a fix

[auvipy]

https://github.com/celery/kombu/pull/769 should fix it