ElzaCS/microservice-arch

Sample currency-conversion app made of multiple micro-services

Microservice-Architecture

Sample currency-conversion app made of multiple micro-services.

Microservices include:

• limits-service: manages constants related to deployment
  • http://localhost:8888/limits-service/default
• currency-conversion-service: calculates equivalent value in currency
  • http://localhost:8100/currency-convertor-feign/from/USD/to/INR/quantity/100
• currency-exchange-service: constants related to currency conversion
  • http://localhost:8000/currency-exchange/from/USD/to/INR
  • http://localhost:8000/h2-console (in-memory db)
• netflix-eureka-naming-server: recognizes various instances of different services for load-balancing and communication between micro-services
  • http://localhost:8761/
• netflix-zuul-api-gateway-server: API gateway for all micro-services to implement common features like authentication/authorization, fallback methods, etc.
  • without gatewayRouter: http://localhost:8765/{app-name}/{uri}
    • http://localhost:8765/currency-exchange-service/currency-exchange/from/USD/to/INR
    • http://localhost:8765/currency-conversion-service/currency-convertor-feign/from/USD/to/INR/quantity/100
  • with gatewayRouter: http://localhost:8765/{uri}
    • http://localhost:8765/currency-convertor-feign/from/USD/to/INR/quantity/100

Dependencies include:

• H2database: In-memory database
• Feign-Client: Useful for creating proxy between microservices
• spring-cloud-loadbalancer: Useful for loadbalancing, imported with project at https://start.spring.io/
• Zuul-Client
• Hystrix
• Eureka-Client: To register each microservice with eureka, useful for load-balancing and communication between microservices
• Sleuth-Client
• Zipkin-Client: For distributed tracing of logs
• RabbitMQ-Client: Useful for communication between micro-services and zipkin

Local Setup

• Requirements include:
  • Setup a local-gitconfig-repo: To fetch limits from limits-service
  • RabbitMQ: For communication between the microservices and Zipkin
  • Zipkin: To trace logs of different microservices at a single place
    • Run at commandline: RABBIT_URI=amqp://localhost java -jar zipkin.jar
    • Default url: http://localhost:9411/zipkin
• Run each microservice as a Java application

Docker Setup

• Building docker images for each microservice: mvn spring-boot:build-image -DskipTests
• Update image name in docker-compose.yaml
• Run docker-compose up