facturio/invoices/tasks.py

import dramatiq
from django.conf import settings
from django.core.files.base import ContentFile
from django.urls import reverse
from gotenberg_client import GotenbergClient

from invoices.models import Invoice


@dramatiq.actor()
def generate_pdf(invoice_id: int):
    invoice = Invoice.objects.get(pk=invoice_id)
    print_url = f'{settings.INTERNAL_API_URL}{reverse("invoices:print_invoice", kwargs=dict(invoice_id=invoice.id))}'

    invoice_file = invoice.files.create()

    with GotenbergClient(settings.GOTENBERG_API_URL) as client:
        with client.chromium.url_to_pdf() as task:
            res = task.url(print_url).run()
            invoice_file.file.save(
                invoice_file.get_file_name('pdf'),
                ContentFile(res.content),
            )