Microservices is a software architecture style where applications are built as a collection of small, independent services that communicate with each other through APIs. Each service is designed to perform a specific task, and they work together to create a larger application. Microservices architecture offers several benefits such as scalability, flexibility, and resilience.

In this tutorial, we will be using Node.js and Express to create microservices. Node.js is a JavaScript runtime built on Chrome’s V8 JavaScript engine, and Express is a popular web framework for Node.js.

Prerequisites

To follow along with this tutorial, you will need the following:

• Node.js installed on your machine
• A code editor like Visual Studio Code
• Basic knowledge of JavaScript and RESTful APIs
• Creating a Simple Microservice

We will start by creating a simple microservice that returns a random number. This microservice will be built using Node.js and Express.

Step 1: Setting up the Project

Open your terminal and create a new directory for your project. Then, navigate into the directory and initialize a new Node.js project using the following command:

mkdir random-number-microservice
cd random-number-microservice
npm init -y

This will create a new Node.js project with a package.json file.

Step 2: Installing Dependencies

Next, we need to install the dependencies for our project. We will be using Express to create our microservice, so let’s install it using the following command:

npm install express

This will install Express and its dependencies.

Step 3: Creating the Microservice

Create a new file called app.js in your project directory. This file will contain the code for our microservice.

First, we need to require the Express module and create a new instance of the Express application:

const express = require('express');
const app = express();

Next, we will define a route for our microservice that will return a random number. Add the following code to your app.js file:

app.get('/random', (req, res) => {
  const randomNum = Math.floor(Math.random() * 100) + 1;
  res.json({ random: randomNum });
});

This code creates a new route for our microservice at the /random endpoint. When a user makes a GET request to this endpoint, the server generates a random number between 1 and 100 and returns it as a JSON response.

Finally, we need to start the server and listen for incoming requests. Add the following code to your app.js file:

const PORT = process.env.PORT || 3000;

app.listen(PORT, () => {
  console.log(`Server listening on port ${PORT}`);
});

This code sets the port for our server to listen on and starts the server.

Step 4: Testing the Microservice

To test our microservice, start the server by running the following command:

node app.js

This will start the server on port 3000. Now, open your web browser and navigate to http://localhost:3000/random. You should see a JSON response with a random number.

Congratulations! You have just created a simple microservice using Node.js and Express.

Microservices architecture offers a lot of benefits for building large-scale applications. In this tutorial, we learned how to create a simple microservice using Node.js and Express. We created a route that generates a random number and returns it as a JSON response. With this example, you can start building more complex microservices for your own applications.