I'm currently writing a chat messenger using GRPC/RabbitMQ for group chats. I have an API in Django/DRF that handles authentication/message logs/text and email alerts etc.
To do this I would like to create a celery task that subscribes to each group message exchange but I'm unclear if there is there a way to bind a celery task to the message exchanges.
Is it realistic/possible to create celery tasks that subscribe to the chat exchanges I create? If not how would you solve/handle these duties?
Quick followup, I found an article that detailed using Kombu and Yosun to publish and/or subscribe via Django.
https://medium.com/#benjamin.pereto/microservices-with-django-events-with-publish-subscribe-9cad1c7aee39
Super helpful!
Related
We need to create a monitor that will show any income calls in our extranet in live time.
We were able to show active calls by using /account/~/extension/~/active-calls, however, to achieve what we need we would need to make a request each second which I guess will be blocked by rate limits.
Is there a better solution for it?
Thanks
Subscription (Push Notification) API resource empowers developers to enable the client application(s) to create a single subscription (to one or more extension's) and continually receive push notifications in real time for each subscribed extension.When using this approach for your application(s) to receive events on your RingCentral account, no polling is involved.
You can create a subscription using either of the below-mentioned transportType for receiving push notifications:
PubNub
WebHook
Notifications which the client wants to receive can be specified by the event filters which are set in the subscription request. The event filter is exposed as a URL, pointing to the required RingCentral API resource. Currently the following event types are available for notifications: extensions, messages and presence. They are described in detail below:
Notifications Event Types
You can take a look at the Subscription API below:
Subscription API
If you are interested in Subscribing to Push notifications via WebHook then we have an Easy-to-follow Quickstart guide here:
RingCentral Webhooks Quickstart Guide
I have enabled the "notify-keyspace-events" for redis node, and getting the event published on key change on subscription.
But, I want to understand, what redis does with the events to be published if there are no subscribers to any key.
Any information or links, which could help me understand will be appreciated.
It is a fire and forget model. If there are no subscribers available, it will drop those events. It will even drop even if the subscriber is not available or will not be able to take those events.
Documentation from Redis:
https://redis.io/topics/notifications
Snippet from documentation,
Because Redis Pub/Sub is fire and forget currently there is no way to
use this feature if your application demands reliable notification of
events, that is, if your Pub/Sub client disconnects, and reconnects
later, all the events delivered during the time the client was
disconnected are lost.
I am using Azure cloud service bus to send and receive messages using AMQP protocol. I have installed proton-c libraries in my debian-linux. I tried the below program to send and receive message from the queue. My requirement is instead of queue I have use topics. Please anyone give me a sample program to use topics in Azure cloud.
import sys, optparse
from proton import *
messenger = Messenger()
message = Message()
message.address = "amqps://owner:<<key>>#namespace.servicebus.windows.net/queuename"
message.body = "sending message to the queue"
messenger.put(message)
messenger.send()
Instead of queuename in above url if I give the topic name then the program running forever. Please someone help me. I am new to python programming.
I found myself the solution for this problem. I guess very few people are working in Azure Cloud so I didn't get any answers.
Here is the solution:
If we create topics in Azure service bus, it always select the checkbox "Enable Partitioning". AMQP protocol doesn't support partitioning topics/queues so I stuck with above issue. Once I deleted the topic and recreate the same topic without select the checkbox "Enable Partitioning". Its work fine. :)
I am developing a news feed backend for multiple applications. The idea is that a user can subscribe to multiple groups and receive posts from the groups that he is subscribed to via push.
I was thinking of: on creating a new post have a create_post_task(content) that goes to the Celery feed queue, so that Celery workers can consume it. What I am not sure is what should I do afterwards to deliver the posts to the clients, dynamically create a new RabbitMQ queue for each group, and route the posts to the respective queue, so that subscribed clients will be pushed the posts from those queues? If so, how do I do that after the task was consumed? Is having a lot of RabbitMQ/Celery queues a problem? Any suggestions on an effective solution would be valuable.
I have now succesfully setup Django-celery to check after my existing tasks to remind the user by email when the task is due:
#periodic_task(run_every=datetime.timedelta(minutes=1))
def check_for_tasks():
tasks = mdls.Task.objects.all()
now = datetime.datetime.utcnow().replace(tzinfo=utc,second=00, microsecond=00)
for task in tasks:
if task.reminder_date_time == now:
sendmail(...)
So far so good, however what if I wanted to also display a popup to the user as a reminder?
Twitter bootstrap allows creating popups and displaying them from javascript:
$(this).modal('show');
The problem is though, how can a celery worker daemon run this javascript on the user's browser? Maybe I am going a complete wrong way and this is not possible at all. Therefore the question remains can a cronjob on celery ever be used to achieve a ui notification on the browser?
Well, you can't use the Django messages framework, because the task has no way to access the user's request, and you can't pass request objects to the workers neither, because they're unpickable.
But you could definitely use something like django-notifications. You could create notifications in your task and attach them to the user in question. Then, you could retrieve those messages from your view and handle them in your templates to your liking. The user would see the notification on their next request (or you could use AJAX polling for real-time-ish notifications or HTML5 websockets for real real-time [see django-websocket]).
Yes it is possible but it is not easy. Ways to do/emulate server to client communication:
polling
The most trivial approach would be polling the server from javascript. Your celery task could create rows in your database that can be fetched by a url like /updates which checks for new updates, marks the rows as read and returns them.
long polling
Often referred to as comet. The client does a request to the server which pends until the server decides to return something. See django-comet for example.
websocket
To enable true server to client communication you need an open connection from the client to the server. django-socketio and django-websocket are examples of reusable apps that make this possible.
My advice judging by your question's context: either do some basic polling or stick with the emails.