How to communicate two or more microservices in django rest framework?

Question:

I have been looking to communicate two or multiple microservices in django and need to make them communicate with each. I’ve reasearched about it and didnt get proper info about it. what i understood is each microservices application completely dont depend on one another including the database. Now how to communicate each microservices with one another. there are 2 methods **synchronous and asynchronous ** method.

i dont want to use synchronous. how to communicate the endpoints of api in asynchronous way? i found some message brokers like rabbitMQ, kafka, gRPc… Which is the best brokers. and how to communicate using those service? i didnt get any proper guidance. I’m willing to learn , can anybody please explain with some example ? It will be huge boost for my work.

Asked By: janezio

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Answers:

There are a few different ways to communicate between microservices in a Django Rest Framework (DRF) application. Here are a few options:

Use HTTP requests: One option is to use HTTP requests to send data between microservices. This can be done using the requests library in Python or using JavaScript’s fetch API in the frontend.

Use a message queue: Another option is to use a message queue, such as RabbitMQ or Kafka, to send messages between microservices. This can be useful if you need to decouple the services and handle asynchronous communication.

Use a database: You can also use a database, such as PostgreSQL or MongoDB, to store data that is shared between microservices. This can be done using Django’s ORM or a database driver in your preferred language.

Which method you choose will depend on your specific requirements and the nature of the communication between your microservices.

Answered By: ABDUL AZIZ KHAN

Because you are starting out, I suggest that you go with RabbitMQ. RabbitMQ is easier to set up and use than Apache Kafka.

Then it depends on what kind of asynchronous communication you are looking for. For example, if you have two microservices; A and B, and you want A to communicate with B, do you want the microservice B to send a response back to A? Or do you want microservice B just to process some task (like send an email) and don’t respond back to A?

Here is a simple example of how to use RabbitMQ in your Django project to process some tasks:

First, you will need to install django-rabbitmq package to help you communicate with the RabbitMQ broker on both the microservices, sender and reciever:

pip install django-rabbitmq

Then add django_rabbitmq to your INSTALLED_APPS setting and create a RABBITMQ_CONFIG dictionary in your Django settings file with the connection details for your RabbitMQ server on both the microservices:

RABBITMQ_CONFIG = {
    'default': {
        'host': 'localhost',
        'port': 5672,
        'user': 'guest',
        'password': 'guest',
    },
}

Finally, in microservice A, use the django_rabbitmq.publishers.Publisher class to publish messages to RabbitMQ:

from django.shortcuts import render
from django_rabbitmq import publishers

def send_message(request):
    # Connect to RabbitMQ and declare a queue
    publisher = publishers.Publisher(queue_name='my_queue')

    # Send a message
    publisher.send_message('Hello World!')

    return render(request, 'send_message.html', {})

And create a management command in microservice B to consume messages from the queue. You can do this by creating a file management/commands/consume_messages.py with the following code:

from django.core.management.base import BaseCommand
from django_rabbitmq import consumers

class Command(BaseCommand):
    help = 'Consumes messages from the specified queue'

    def add_arguments(self, parser):
        parser.add_argument('queue_name', type=str, help='The name of the queue to consume messages from')

    def handle(self, *args, **options):
        queue_name = options['queue_name']

        # Define a callback function to process the received message
        def callback(ch, method, properties, body):
            print(" [x] Received %r" % body)

        # Create a message consumer and start consuming messages from the queue
        consumer = consumers.Consumer(queue_name, callback)
        consumer.start_consuming()

Don’t forget to start the command to actually start processing tasks from the RabbitMQ:

python manage.py consume_messages my_queue

You can check out RabbitMQ Getting Started Page to get started using RabbitMQ. And you can find more information and examples in the django-rabbitmq documentation.

Answered By: Harith