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Exploring Implementation Details in Code

Exploring Implementation Details in Code

Learn how to implement the producer-consumer pattern in code using Kafka libraries, setting up producer and consumer components with event handling.

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There are several ways in which the producer-consumer pattern can be implemented in code. Some samples can be downloaded and run, along with custom implementations that we might find in domain libraries or core (shared) libraries. Let’s look at sample code that uses the Confluent libraries for Kafka, which provide a simple and easy-to-understand abstraction layer for interacting with Kafka. We need to ensure that we have Docker installed because the installation is dependent upon running the docker compose command. The start order for this example code will be to run the docker-compose up command, then right-click on the consumer project and select the “Debug > Start New Instance” option, then right-click on the producer project and select the “Debug > Start New Instance” option.

The producer code

Let’s start with the producer code, which can be set up using the minimal API feature in ASP.NET Core. To begin, create a new project in Visual Studio using the empty ASP.NET Core application template. The following figure shows the template after utilizing a search with “C#” set as the language and “Web” set as the project type:

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The new project dialog in Visual Studio showing the empty ASP.NET Core project template
The new project dialog in Visual Studio showing the empty ASP.NET Core project template

Next, we want to add some references to the project to enable the Swagger documentation of the service, the hosting of background services in the service, and the dependency injection mechanism in ASP.NET Core to resolve types appropriately. To do this, we can right-click on the project and select the “Manage NuGet packages” option. Alternatively, we can run the following code to install the packages within the project: 

dotnet add package Confluent.Kafka
dotnet add package Microsoft.Extensions.Hosting
dotnet add package Microsoft.Extensions.DependencyInjection
dotnet add package Swashbuckle
dotnet add package Swagger
Code to install packages within the project

When we open the main Program.cs file, notice that there are no namespace declarations, no main method definitions, and no using statements. This is because the top-level program feature is employed to make the main code file concise and easy to read. The Startup.cs file is no longer required either, which makes setting up a basic web API project very simple and much quicker than previous framework versions. The following code is an example of what will be in our Program.cs file when we first create the project: 

var builder = WebApplication.CreateBuilder(args);
var app = builder.Build();
if (app.Environment.IsDevelopment())
{
    app.UseDeveloperExceptionPage();
}
app.MapGet("/", () => "Hello World!");
app.Run();
The Program.cs file

We need a way to allow this service to produce a ...