Celery group multiple tasks in one design - django

Question

I just getting familiar with Celery and have a question. My setup is Django-Redis-Celery
Lets take an example of a task sending email:
TASKS
#task
def send_email(message):
mailserver.sendOneMessage(message)
VIEWS
class newaccount(APIView):
def post(self, request, format=None):
send_email.delay(request.data.email)
This works perfectly, Django sends messages to Redis and those are picked up by Celery then to execute task. But I want to improve the system so that Celery picks up all messages from Redis at certain intervals and executes a single task with multiple messages. This because, connecting to the email server is slow and sending multiple messages as a single request will result in a faster process.
I want something like this to work:
TASKS
#task
def send_emails(messages):
mailserver.sendMultipleMessages(messages)
Thoughts?

Answer 1

Since i am using redis as a cache (django-redis) already i implemented the following workflow:
Step 1. Create a task that adds new emails to cache
#shared_task()
def add_email(user_id):
cache.set("email#{}".format(user_id), None, timeout=None)
Step 2. Create a periodic task that runs every second and looks up for new emails in the cache
class ProcessEmailsTask(PeriodicTask):
run_every = timedelta(seconds=1)
def run(self, **kwargs):
call_email()
def call_email():
item_exists = True
ids = []
while item_exists:
try:
key = next(cache.iter_keys("email#*"))
ids.append(key.split("email#")[1])
cache.delete_pattern(key)
except:
item_exists = False
if len(ids) > 0:
send_emails_to(ids)
Step 3. Run both celery workers and celery beat and profit!