WebSocket for real-time communication in C# and Typescript — Part 5 (Scaling- Apache Kafka)

In our previous blog we added Security now we will add Scaling.

Scaling a WebSocket server can be a bit more challenging than scaling a traditional HTTP server because WebSockets are full-duplex connections that can stay open for long periods of time. Here are a few ways you can scale a WebSocket server:

Load balancing:

One way to scale a WebSocket server is to use a load balancer that can distribute incoming connections to multiple servers. This can help to distribute the load and ensure that the servers are not overwhelmed. You could use a hardware load balancer or a software load balancer like HAproxy, NGINX, or AWS Elastic Load Balancer.

For example, you can use HAproxy as a load balancer for your WebSocket server. You can configure HAproxy to forward incoming WebSocket connections to a pool of backend servers. In this case, you need to make sure that the HAproxy is configured to use the proxy-protocol to forward the client information along with the connection to the backend server.

Reverse Proxying:

Another way to scale a WebSocket server is to use a reverse proxy, which can handle the WebSocket protocol and forward connections to a pool of backend servers. This can help to improve the performance and scalability of the WebSocket server by offloading some of the work to the reverse proxy.

For example, you can use NGINX as a reverse proxy for your WebSocket server. You can configure NGINX to handle the WebSocket protocol and forward connections to a pool of backend servers. In this case, you need to make sure that the NGINX is configured to use the proxy_protocol to forward the client information along with the connection to the backend server.

Apache Kafka:

Another way to scale a WebSocket server is to use Apache Kafka, which is a distributed streaming platform that can handle high throughput and low latency message passing. By using Apache Kafka as a message broker, you can distribute the messages between servers and handle a large number of connections.

For example, you can use Apache Kafka to handle the messages between your WebSocket server and the clients. The WebSocket server can publish the messages to a Kafka topic and the clients can consume the messages from the same topic. In this way, you can handle a large number of connections and distribute the messages between multiple servers.

In order to use Apache Kafka with your WebSocket server, you need to install and configure Apache Kafka, and also you need to write code to interact with the Kafka topic and handle the messages. You can use a Kafka client library for your programming language of choice, like librdkafka for C#, to interact with the kafka topic.

It’s worth noting that, using Apache Kafka for WebSocket server requires a bit more setup and maintenance, but it offers a high-performance message passing system that can handle a large number of connections and messages. As with any scaling strategy, it’s important to monitor the performance of your servers and adjust the configuration as needed.

Here is an example of how you might use Apache Kafka to handle messages between a WebSocket server and clients in C#:

First, you need to install the Confluent.Kafka nuget package, this package is a .NET client for Apache Kafka that provides an easy way to interact with the Kafka topics.

In this example, the WebSocket server is configured to use Apache Kafka as a message broker. When a message is received from a client, the server is publishing the message to a Kafka topic, and the clients can consume the messages from the same topic.

It’s worth noting that, this is just a simple example, in a real-world scenario you might need to handle additional requirements like message serialization, error handling, and more.

It’s also worth noting that, using Apache Kafka requires additional setup and maintenance but it offers a high — performance message passing system that can handle a large number of connections and messages. However, you need to make sure that your Apache Kafka cluster is properly configured and running smoothly.

Another thing worth noting is that this example is using the producer API of the Confluent.Kafka package, you can use the consumer API of the same package to consume the messages from the same topic in the client side, this will give you a basic setup for a pub-sub messaging system.

It’s also important to consider that, this example is only handling the messaging aspect of the WebSocket, you will need to handle other aspects of your application as well, like authentication, security, and other requirements that your application needs.

It’s important to monitor the performance of your servers and adjust the configuration as needed, also make sure to keep track of the messages that are being sent and received, this will help you identify any issues or bottlenecks in your system.