README.md

Microservices-Java

Repo Information

Spring Config Server - localconfig

• for external configuarions
• Has configurations for dev, qa and prod

Spring Config Client - limits-service

• uses the external configuration from the git repo
• does not depend on applications.properties of itself for setting the configuration

JPA connection - currency-exchange-service

• is used for for providing currency conversion rate from one currency to another currency
• has jpa connection to the in-memory database - h2

Rest Template and feign Client - currency-conversion-service

• is used to connect to currency-exchange-service to get conversion rate and do the conversion
• used rest template to pass the data ans then used feign client to remove the bolierplate code

Client side load balancing - Ribbon - currency-conversion-service

• since currency-conversion-service calls currency-exchange-service, we have made multiple replicas of the currency-exchange-service, and have hardcoded the endpoints of it in currency-conversion-service application.properties file.
• Is it used for client side load balancing.

Client side load balancing - Eureka+Ribbon - netflix-eureka-naming-server

• to remove the hardcoded enpoints of currency-exchange-service
• let currency-conversion-service discover the working endpoints if currency-exchange-service, we register all the services to the eureka server(service discovery)

ZUUL API Gateway - Server Side Load Balacing

• the external client interacting with the application are not aware of the different services running on ther server
• provides and common point for the clients to interact
• vulnerbale to single point of failure(use duplicates)

Spring cloud Sleuth

• Provides a unique ID to all the request which are generated between communication of microservices.
• This helps in identification of particular request in the logs and find traces

Rabbit MQ

• added pom dependency in all the microservices so that they can send the logs to centralized server through mq broker

Distributed Tracing - Zipkin

• microservices are dependent on each other.
• If one fails, it can affect other services.
• Hence, we have to keep track of all the request in one centralized server which will help to get all the information we needed while finding the fault
• Is connected to a database(currecntly, h2 database), to store all the logs

Spring Cloud Bus

• While keeping external configuration
• If we have 100s of replicas of particular service refreshing it for every replica becomes difficult
• Hence, spring cloud bus dependency

Fault Tolerance -Hystrix

• As services are dependent on each other.
• If one fails, it will create fallback loop and it will keep cascading till it will create a delay in result which has to be displayed client.
• Using fallback method instead to inform thr user that there is goign to be delay.