redis-microservices-demo

This project is to demonstrate how we can implement Redis in a microservice architecture. So here I have implemented Redis in a Spring Boot service, and here data will be stored in the Redis cache if it's pass certain criteria, and when users ask for that particular data we will return it from the cache instead of taking that data from the database, as well as we will update and delete data from the cache.

We have here Zuul API Gateway which is the proxy for our microservice architecture, and it takes care of the load balancing and forward requests to the particular service.

We have here Eureka Server which registers the Services and Zuul API Gateway.

This is a high-level overview of what I have built, and the detailed information for all the components available below.

Requirements To Run Applications

• JDK 8
• MySQL
• Redis
• IDE

Dependencies And Tools Used To Build Applications

• Git
• JDK 8
• Gradle
• Maven
• Spring Boot Web
• Spring Boot Data JPA
• MySQL
• Redis
• Lombok
• IDE
• Eureka Client
• Eureka Server
• Zuul Proxy
• Hystrix

Eureka Server

Eureka Server is an application that holds information about all client-service applications.

Every Microservice will register into the Eureka server and the Eureka server knows all the client applications running on each port and IP address.

Eureka Server is also known as Discovery Server.

To Run "eureka-server"

1. Go to the /redis-microservices-demo/eureka-server directory and open terminal

2. Execute the following command in the terminal

   gradlew bootrun
   

   or go to the /redis-microservices-demo/eureka-server/src/main/java/com/eurekaserver directory and run the EurekaServerApplication class.

And now we can access the Eureka Server on this link: Eureka Server

You will see here registered Services and Zuul API Gateway once we start them.

redis-spring-boot-service

This is a spring boot service and I have implemented Redis here for catching, and initially, all the data are stored in the MySQL. So here I built this service similar to Instagram here we have users and their followers, so I put a condition to store users in the cache and the condition is if the followers > 12,000 then the users will be stored in the cache.

So when you get the user by id using GET By Id API and if the user has passed the condition, then it will be stored in the cache and when you next time hit this API the user will be returned from the cache, and you won't see any logs in your console because we are not getting it from the database.

Similarly when you update the user followers using PUT API for example if you set user's followers < 12,000, then that user will be removed from the cache and when you try to get that user it will return from the database and you will see logs in the console, and if you update user followers > 12,000 so it will be added in the cache and then when you try to get that user it will be returned from the cache.

And when you delete a user using DELETE API, and if the user is available in the cache then it will be removed from the cache and database, and then you will try to get that user you will get NOT FOUND (404) because that user is not available neither in cache nor in database.

Additionally, we have two more APIs POST to add new users and GET All to get all the users.

To Run "redis-springboot-demo" Service

1. Go to the /redis-microservices-demo/redis-springboot-demo directory and open terminal

2. Execute the following command in the terminal

   mvnw spring-boot:run
   

   or go to the /redis-microservices-demo/redis-springboot-demo/src/main/java/com/redis/springbootdemo directory and run the RedisSpringBootDemoApplication class.

You can run the multiple instances of this service and access them using ZUUL Gateway, here is the collection of APIs import them in your POSTMAN and play with the APIs.

NOTE: make sure ZUUL Gateway is up and running before you access APIs

Zuul API Gateway

Zuul Server is an API Gateway application. It handles all the requests and performs the dynamic routing of microservice applications. It works as a front door for all the requests. It is also known as Edge Server.

Zuul is built to enable dynamic routing, monitoring, resiliency, and security. Here we are covering dynamic routing and resiliency.

We have implemented Hystrix to make our gateway resilient, so we have a fallback mechanism here, in case the services are not available, so the user can get a nice readable message instead of nasty errors.

To Start "zuul-gateway-service"

1. Go to the /redis-microservices-demo/zuul-gateway-service directory and open terminal

2. Execute the following command in the terminal

   gradlew bootrun
   

   or go to the /redis-microservices-demo/zuul-gateway-service/src/main/java/com/zuulgateway directory and run the ZuulGatewayServiceApplication class.

And now we can access the services through this gateway. I request you to start multiple instances of the redis-springboot-demo. So you can see that the requests are forwarding to the multiple instances to balance the load.

Thank You