Consuming Kafka Topics with C#

Wednesday, February 9th, 2022

Apache Kafka is a popular open-source distributed event streaming platform that allows you to process, store and analyze large amounts of data in real-time. The publish-subscribe model of Kafka allows multiple consumers to subscribe to one or more topics and receive messages in real-time as they are produced by the producers. In this blog post, we will look at how to consume Kafka topics in C#.

Prerequisites

1. A running instance of Apache Kafka
2. A topic created in the Kafka cluster
3. Visual Studio or any other development environment
4. Confluent.Kafka library installed in your development environment

Consuming Topics

To consume topics in C#, you will need to use a Kafka client library that provides a high-level API for working with Kafka. Confluent.Kafka is a popular .NET client library for Apache Kafka that provides a simple, high-level API for consuming and producing messages.

The first step is to install the Confluent.Kafka library using the NuGet package manager in Visual Studio. Once the library is installed, you can create a new console application in Visual Studio.

Next, you will need to create a ConsumerConfig object that contains the configuration information for your Kafka consumer, such as the Kafka broker addresses, the topic you want to subscribe to, and the group ID of the consumer group.

var config = new ConsumerConfig
{
    BootstrapServers = "localhost:9092",
    GroupId = "your-consumer-group",
    AutoOffsetReset = AutoOffsetReset.Earliest
};

Once you have the ConsumerConfig object, you can create a KafkaConsumer object and subscribe to the topic using the Subscribe method.

using var consumer = new ConsumerBuilder<Ignore, string>(config).Build();
consumer.Subscribe("your-topic");

Finally, you can use a while loop to poll the topic for messages and process them as they arrive. You can use the Consumer.Consume method to poll for new messages in the topic.

while (true)
{
    var message = consumer.Consume();
    Console.WriteLine($"Received message: {message.Value}");
}

Conclusion

In this blog post, we looked at how to consume topics in C# using the Confluent.Kafka library. With just a few lines of code, you can start consuming messages from a Kafka topic and processing them in real-time. The Confluent.Kafka library provides a high-level API for working with Apache Kafka, making it easy for C# developers to integrate with Kafka and build scalable, real-time event-driven applications.

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