Table of contents

• Introduction
• Purpose of Gateway
• Architecture
• Tools and Technologies

Introduction

The first step to secure a web application is by having authentication and authorization functionality. Authentication checks the user identity, whereas authorization checks whether the user has access to a specific resource. Thanks to Spring, all we have to do is configure security such that it provides authentication and authorization, and we don't have to write the logic for ourselves.

Purpose of Gateway

When a web application is monolithic, all the services that include authentication service, user service will be served from a single server. Now, the industry is moving away from monolithic to microservice-based architecture. The advantage of microservices are plenty and I will not go into deep. But in short, microservices decouples tightly integrated services that help us to scale and deploy independently. So in my project, I have 3 different spring boot-microservices,

1. User service
2. Agreement service
3. Notification service

Now the question would be, how do we forward the request to the right microservices? The answer would be a gateway. I have developed my project extensively using spring boot, so I am using Spring cloud gateway. A gateway acts as an interface between a user and microservices. The user will send a request to the gateway and the gateway will route the request to the corresponding microservices. We will have to configure the gateway and provide routing information to it.

Advantages of Gateway

• We don't have to expose microservices to the internet.
• Gateway can perform authentication for a given request, instead of each microservice performing their authentication and authorization. This promotes microservices to be stateless.
• We can have circuit breakers, if a microservice goes down we can forward the request to the landing page that shows service is down.

Architecture

Tools and Technologies

• Spring cloud gateway - A non-blocking i/o gateway that routes the request to the microservices.
• Spring eureka - Helps with dynamic IP resolution for microservices registered with eureka.
• OpenID connect - Using Facebook and Google for the sign-in option.
• Slf4j - For logging information.
• Redis - To store session information that can be scaled.
• Language - Java 11