Django Simple asynchronous email backend (Celery 3.1+)

asyncemail.py

from celery import shared_task
from celery.contrib.methods import task_method
from django.core.mail.backends.smtp import EmailBackend as BaseEmailBackend


class FakeLock(object):
    __enter__ = lambda x: None
    __exit__ = lambda a, b, c, d: None


class EmailBackend(BaseEmailBackend):
    """
    A wrapper that manages the SMTP network connection asynchronously
    """

    def __init__(self, *args, **kwargs):
        super(EmailBackend, self).__init__(*args, **kwargs)

        # fake lock object, because base methods use this
        # celery doesn't support base RLock class serialization. Fixing it.
        self._lock = FakeLock()

    def send_messages(self, email_messages):
        self._send_messages.apply_async((self, email_messages))

        return len(email_messages)

    @shared_task(filter=task_method, name="send_emails")
    def _send_messages(self, email_messages):
        return super(EmailBackend, self).send_messages(email_messages)

settings.py

# Path to class in your environment
EMAIL_BACKEND = 'project.portal.backends.asyncemail.EmailBackend'

# Don't forget add backend module to celery configuration, because it is not placed in app.tasks module and need to be defined.
CELERY_IMPORTS = ['project.portal.backends.asyncemail']

# json doesn't support serialization for python objects, only simple types.
CELERY_TASK_SERIALIZER = 'pickle'