Building Scalable Microservices with NestJS and Kafka
In today’s fast-paced digital landscape, building scalable and reliable applications is crucial for businesses to stay competitive. One approach to achieving this is by using microservices architecture, which allows for the development of complex systems as a collection of small, independent services. In this article, we’ll explore how to build microservices using NestJS and Kafka, a powerful combination that enables scalable, reliable, and easy-to-maintain systems.
What are Microservices?
Microservices are an architectural pattern that follows the Service-Oriented Architecture (SOA) concept. In a microservices architecture, a complex system is broken down into smaller, independent services that communicate with each other using lightweight protocols. Each service is responsible for a specific business capability and can be developed, tested, and deployed independently of other services in the system.
Why Use NestJS and Kafka?
NestJS is a popular Node.js framework for building server-side applications, while Kafka is a distributed streaming platform designed for high-throughput and fault-tolerant data processing. Together, they provide a powerful combination for building scalable microservices. NestJS provides a robust framework for building server-side applications, while Kafka enables efficient communication between microservices.
Setting Up the Project Workspace
To get started, let’s set up the project workspace. First, ensure that you have Apache Kafka installed and running on your local machine. Next, create a new Nx workspace using the following command:
npx create-nx-workspace myworkspace --preset=empty
Specify the nest option while creating the workspace and name the application api-gateway. Once the workspace is created, install the project dependencies by running the following commands:
npm install
npm run build
Creating the Auth Microservice
Next, let’s create the auth microservice. Run the following command to create a new NestJS application:
npx nest new auth-microservice
In the main.ts file, remove the boilerplate code and replace it with the NestFactory.createMicroservice() method. Pass the AppModule in the first argument and the Kafka transport object in the second argument of the createMicroservice() method.
Adding the Payments Microservice
Now that the auth microservice is up and running, let’s add a payments microservice. Run the following command to create a new NestJS application:
npx nest new payments-microservice
In the main.ts file, remove the boilerplate code and replace it with the NestFactory.createMicroservice() method. Pass the AppModule in the first argument and the Kafka transport object in the second argument of the createMicroservice() method.
Building the Microservice App
To complete the payments microservice, add the event handler for the process_payment event in the AppController. Use the @EventPattern() decorator to consume the event and process the payment accordingly.
Running and Testing the Services
To test and see all the services in action, run the following commands individually on separate terminals:
npm run start:auth-microservice
npm run start:payments-microservice
npm run start:api-gateway
Use Postman to test the API endpoints. Select the /api/auth/signup API to create a user, and then call the /api/payments/pay API to process a payment with the user ID and amount.
By following these steps, you can build a robust application using microservices architecture with NestJS and Kafka. This stack provides a scalable, reliable, and easy-to-maintain system that is perfect for building complex applications.