I have django 1.11.5 app with celery 4.1.0 and I recived all the time:
kombu.exceptions.EncodeError: <User: testuser> is not JSON serializable
my settings.py:
CELERY_BROKER_URL = 'amqp://localhost'
CELERY_RESULT_BACKEND = 'amqp://localhost'
CELERY_ACCEPT_CONTENT = ['application/json']
CELERY_RESULT_SERIALIZER = 'json'
CELERY_TASK_SERIALIZER = 'json'
CELERY_TIMEZONE = 'Asia/Makassar'
CELERY_BEAT_SCHEDULE = {}
tasks.py
from __future__ import absolute_import, unicode_literals
from celery import task
from django.contrib.auth.models import User
@task(serializer='json')
def task_number_one():
user = User.objects.create(username="testuser", email="[email protected]", password="pass")
return user
I call task in the view:
def form_valid(self, form):
form.instance.user = self.request.user
task_number_one.delay()
return super().form_valid(form)
This is because you are using the JSON serializer for task serialization (as indicated by the setting CELERY_TASK_SERIALIZER = 'json'
), but you are trying to return a model instance (which cannot be serialized into JSON).
You have two options:
1) Don't pass the instance, pass the primary key of the instance and then look up the object inside your task.
2) Use the pickle
task serializer instead. This will allow you to pass objects as arguments to your tasks and return them, but comes with it's own security concerns.
The error is because of Celery expecting a JSON
data from your task function while you returned a User
instance.
How to solve this ?
You are not using that return data anywhere, so you don't have to return it. That is you can remove return user
from the task function.
Or,
return a Json
data from the task function will solve this issue as well
Solution 1
@task(serializer='json')
def task_number_one():
user = User.objects.create(username="testuser", email="[email protected]", password="pass")
Solution 2
@task(serializer='json')
def task_number_one():
user = User.objects.create(username="testuser", email="[email protected]", password="pass")
# return some json data instead of `USER` instance
return {"status": True} # Change is here
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