NestJS Microservices with TCP (2024)

NestJS Microservices with TCP.

A microservice is an application that uses a transport layer other than HTTP. In this example microservices Communicate with each other using TCP.

Table of contents:

• General Introduction — What is Microservice
• Why Microservice
• NestJS Microservices Overview
• Microservice Client
• User Microservice
• Conclusion

General Introduction — What is Microservice:

• The microservice architecture enables an organization to deliver large, complex applications rapidly, frequently, reliably and sustainably.
• In a microservice, each software application feature is separated from the other, in most cases with their respective servers and databases.

Why Microservice:

• Microservice offers flexibility and performance benefits that can’t be achieved with a monolithic application.
• The event-driven architecture of Node.js makes it a perfect choice for microservices, being fast, highly scalable, and easy to maintain.

1. 1. 1. 1. 1. 1. 1. • Independently deployable
                     • Loosely coupled
                     • supports distributed development
                     • better scalability
                     • faster development cycles
                     • isolated services are easier to debug and maintain

NestJS Microservices Overview:

• It supports different approaches such asRequest ResponseandEvent-Based.
• we will be looking at Nest JS Microservice usingRequest Response approach with TCP Transporter.
• l which will be responsible for operations and we will usePacket Senderfor testing purposes, an open-source application that allows us to send network packets that supportTCP.
• Asynchronous patternwithTCPpackets which we will communicate with our microservice, and hence the choice of Nest.JS as it has many built-in features making it easier for us to create a microservices architecture.

First, you need to install Nest JS, Runnpm i -g @nestjs/cli

Microservice Client:

• Runnest new nest_producerto create the Client service. Relocate the project directory and run the project.

start:devfor watch the changes in your files. To create the app as microservice, we need to install the required package:

npm i — save @nestjs/microservices

Go tomain.tsfile and re-write the code as given below:

• NestFactoryexposes a few static methods that allow creating an application instance. The create() method returns an application object, which fulfills the INestApplication interface.

Go toapp.module.tsand replace the code as given below:

Runnest g resource usercommand generates all the NestJS building blocks (module, service, controller class, entity class, DTO classes ,testing (.spec) files).

• Clients Module exposes the static register() method.
• This method takes an argument which is an array of objects representing microservices.
• Each such object has a name property as well as a microservice-specific options object.

• In this example, Register the user details (name, email ,password ,phone number)
• we can send a message using the send()method of the Client Proxy instance. The send() method takes the message pattern and the actual data or the payload as input.
• Client service send Request with Message pattern{cmd:’register_user’}to User service.

User Microservice:

Runnest new user_service to create the User service.Relocate the project directory and run the project.

we need to install the required package:

npm i — save @nestjs/microservices

Go tomain.tsfile and re-write the code as given below:

• The INest Application instance can be connected with INest Microserviceinstances through theconnect Microservice()
• To connect multiple microservice instances, issue the call to connect Microservice() for each microservice.
• This method takes an argument which is an objects representing microservices communication transport and options.

Go toapp.module.tsand replace the code as given below:

• Runnest g resource user command generates all the NestJS building blocks. Runnpm install — save typeorm
• In this example , we choose the MySQL database and Create database name nestdb.

Now go tosrcand Createdata-source.tsfile to add code as given below:

Go to User Module folder intouser.module.tsand write the code as given below:

Add the given code User Entity folder intouser.entity.tsfile.

Go touser.controller.tsfile and re-write the code as given below:

Add given below code intouser.service.ts

Open your postman and send action withlocalhost:5000/register_user

Conclusion:

we have learnt how to create aNestJS Microservices with TCPusing Request Response approach.NestJS makes it possible to create outstanding, well-organized, and lightweight microservices. The framework allows you to create extensible software solutions where there is no strong coupling between the components.