Django Генерация Excel и сохранение в виде объекта с помощью Celery и RabbitMQ

Я использую Django 2.2.5, Celery 5.2.6 и RabbitMQ и я новичок в последней версии 2.

Я хочу сгенерировать лист Excel и сохранить его в поле FileField внутри вновь созданного объекта (не загружать его), и вот что я сделал:

project/settings.py:

CELERY_RESULT_BACKEND = "django-db"
CELERY_CACHE_BACKEND = "django-cache"
CELERY_BROKER_URL = "amqp://localhost"

CELERY_ACCEPT_CONTENT = ["application/json"]
CELERY_TASK_SERIALIZER = "json"
CELERY_RESULT_SERIALIZER = "json"
CELERY_TIMEZONE = "Africa/Casablanca"

project/celery.py:

from __future__ import absolute_import, unicode_literals

import os
from celery import Celery

os.environ.setdefault("DJANGO_SETTINGS_MODULE", "verautonoapi.settings")

app = Celery("verautonoapi")

app.config_from_object("django.conf:settings", namespace="CELERY")
app.autodiscover_tasks()


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

project/init.py :

from __future__ import absolute_import, unicode_literals

# This will make sure the app is always imported when
# Django starts so that shared_task will use this app.
from .celery import app as celery_app

__all__ = ("celery_app",)

app/tasks.py:

from __future__ import absolute_import, unicode_literals
from django.http import HttpResponse, FileResponse
from celery import shared_task
from celery.utils.log import get_task_logger
from time import sleep

from openpyxl import Workbook
from datetime import date
from .models import Dossier, Export

logger = get_task_logger(__name__)


@shared_task(bind=True, track_started=True)
def exp_en_cours(request):
    print("task activated")
    sleep(7)
    print("now starting generating the file")
    dossier_queryset = Dossier.objects.filter(status_admin="Validation OR Requise")
    today = str(date.today())
    response = FileResponse(
        content_type="application/vnd.openxmlformats-officedocument.spreadsheetml.sheet",
    )
    response["Content-Disposition"] = (
        "attachment; filename=" + today + "-dossiers_en_cours.xlsx"
    )
    workbook = Workbook()

    # Get active worksheet/tab
    worksheet = workbook.active
    worksheet.title = "Dossiers en cours"

    # Define the titles for columns
    columns = [
        "Numéro",
        "Créé le",
        "Assurance",
        "Prestataire",
        "Matricule",
    ]

    row_num = 1

    # Assign the titles for each cell of the header
    for col_num, column_title in enumerate(columns, 1):
        cell = worksheet.cell(row=row_num, column=col_num)
        cell.value = column_title

    # Iterate through all movies
    for dossier in dossier_queryset:
        row_num += 1

        # Define the data for each cell in the row
        row = [
            dossier.numero,
            str(dossier.date_posted)[:10],
            dossier.assurance.name,
            dossier.created_by.user.username,
            dossier.matricule,
        ]

        # Assign the data for each cell of the row
        for col_num, cell_value in enumerate(row, 1):
            cell = worksheet.cell(row=row_num, column=col_num)
            cell.value = cell_value

    workbook.save(response)

    Export.objects.create(status="Dossier en cours", file=response)

    return "OK"

app/models.py:

class Export(models.Model):
    STATUS = [
        ("Dossier en cours", "Dossier en cours"),
        ("Dossier validés", "Dossier validés"),
        ("Dossier rejetés", "Dossier rejetés"),
        ("Dossier à clôturer", "Dossier à clôturer"),
        ("Dossier clôturés", "Dossier clôturés"),
        ("Dossier facturés", "Dossier facturés"),
        ("Dossier archivés", "Dossier archivés"),
    ]
    status = models.CharField(max_length=20, choices=STATUS, null=True, blank=True)
    timestamp = models.DateTimeField(auto_now_add=True, editable=False)
    file = models.FileField(
        upload_to=get_rapport_filename, verbose_name="Fichiers Excel"
    )

    def __str__(self):
        return "%s - %s" % (self.dossier, self.timestamp)

    class Meta:
        verbose_name = "Rapport Excel"
        verbose_name_plural = "Rapports Excel"

Я также установил django_celery_results и добавил его в установленные приложения.

Когда я выполняю задание, оно выдает следующую ошибку:

This FileResponse instance is not writable

Я пробовал и на Windows, и на Linux (на digitalocean) и получаю ту же ошибку. Подскажите, что я делаю не так? Функция excel не верна? Потому что я внес в нее изменение, чтобы она не загружалась (заменил HttpResponse на FileResponse). Или это RabbitMQ и Celery?

from io import BytesIO
from django.core.files.base import ContentFile

vworkbook = BytesIO()
workbook.save(vworkbook)

content = vworkbook.getvalue()

try:
    Export.objects.create(
        status="Dossiers archivés",
        file=ContentFile(
            content, name="dossiers_archivés-" + str(date.today()) + ".xlsx"
        ),
    )
    return "EXP_ARCH OK"
except Exception:
    raise Exception