Heroku app cannot connect to Celery worker

Question

I have created a Django app which is using Celery for task processing. It’s working fine locally but when I pushed it to Heroku, I found that app cannot connect to Celery worker.

I can see worker is running without any problem.

$ heroku ps

=== web (Free): gunicorn my_django_project.wsgi --log-file - (1)
web.1: up 2019/08/10 11:54:19 +0530 (~ 1m ago)

=== worker (Free): celery -A my_django_project worker -l info (1)
worker.1: up 2019/08/10 11:54:19 +0530 (~ 1m ago)

But when I checked the logs I found this error message

2019-08-10T06:04:30.402781+00:00 app[worker.1]: [2019-08-10 06:04:30,402: ERROR/MainProcess] consumer: Cannot connect to amqp://guest:**@127.0.0.1:5672//: [Errno 111] Connection refused.
2019-08-10T06:04:30.402801+00:00 app[worker.1]: Trying again in 32.00 seconds...

Seems like app cannot connect to celery worker.

Project directory structure

Project
|
├── data/
├── db.sqlite3
├── manage.py
├── Procfile
├── README.md
├── requirements.txt
├── my_app/
│   ├── admin.py
│   ├── apps.py
│   ├── __init__.py
│   ├── tasks.py
│   ├── templates
│   ├── tests.py
│   ├── urls.py
│   └── views.py
├── my_django_project/
│   ├── celery.py
│   ├── __init__.py
│   ├── settings.py
│   ├── staticfiles
│   ├── urls.py
│   └── wsgi.py
├── runtime.txt
└── static/

Procfile

web: gunicorn my_django_project.wsgi --log-file -
worker: celery -A my_django_project worker -l info

celery.py

from __future__ import absolute_import, unicode_literals
import os
from celery import Celery

#set the default Django settings module for the 'celery' program.
os.environ.setdefault('DJANGO_SETTINGS_MODULE', my_django_project.settings')

app = Celery(my_django_project)

# Using a string here means the worker doesn't have to serialize
# the configuration object to child processes.
# - namespace='CELERY' means all celery-related configuration keys
#   should have a `CELERY_` prefix.
app.config_from_object('django.conf:settings', namespace='CELERY')

# Load task modules from all registered Django app configs.
app.autodiscover_tasks()

@app.task(bind=True)
def debug_task(self):
    print('Request: {0!r}'.format(self.request))

tasks.py

from celery import shared_task

@shared_task
def task1():

   // do stuff

    return results

Answer 1

amqp://guest:**@127.0.0.1:5672 Refers to the backend celery tries to use, you need to setup a backend either rabbitMQ, Redis or something else.

The docs