Service Discovery and Registry

SERVICE DISCOVERY AND SERVICE REGISTRY:

  • In the current development, the Order service is having inter service communication with Inventory Service.

secomm.png

  • In the production development, every microservice will be deployed on cloud env.
  • We cannot hardcode the ipAddress and the port details as they are dynamic and also we will have multiple instances of the same service.

orderinventory.png

  • In this case how my order service will know to which instance of the inventory service it needs to send the request.
  • If I hard code one of the Ip and port of one of the instance but that instance can go down.
  • Order Service should know that particular instance is down and should call the other instance.
  • For this we have a pattern called Service Discovery and Registry.

servicediscovery.png

  • In service discovery / Discovery service which will store the service name and the ip Address.
  • First At the start of the App /Service they will register with the discovery server by making a request.
  • Whenever they make a request, the server will add the details into its local copy.

STEPS:

  1. Create a discovery service.
  2. Add the dependency in the pom.xml
  3. spring-cloud-starter-netflix-eureka-server
  4. Add the annotation @EnableEurekaServer.
  5. Add the properties in yml file. 
     eureka:
   instance:
     hostname: localhost
       client:
         register-with-eureka: false
           fetch-registry: false

 server:
   port: 8761

6.In the micro service (client) add the dependency . spring-cloud-starter-netflix-eureka-client. 7.Add the annotation @EnableEurekaServer – spring boot 2 @EnableDiscoveryServer – spring boot 3

 eureka:
   client:
     service-url:
       defaultZone: http://localhost:8761/eureka
         register-with-eureka: true
           fetch-registry: true
             enabled: true