Spring Cloud Architecture Based Application

Microservices with Spring Boot and Spring Cloud

Make microservices cloud ready with Spring Cloud

• Establishing Communication between Microservices
• Centralized Microservice Configuration with Spring Cloud Config Server
• Using Spring Cloud Bus to exchange messages about Configuration updates
• Simplify communication with other Microservices using Feign REST Client
• Implement client side load balancing with Ribbon
• Implement dynamic scaling using Eureka Naming Server and Ribbon
• Implement API Gateway with Zuul
• Implement Distributed tracing with Spring Cloud Sleuth and Zipkin
• Implement Fault Tolerance with Zipkin

Microservices Step by Step

Spring Cloud Config Server

• Limits Microservice and Spring Cloud Config Server
• Setting up Limits Microservice
• Creating a hard coded limits service
• Enhance limits service to pick up configuration from application properties
• Setting up Spring Cloud Config Server
• Installing Git
• Creating Local Git Repository
• Connect Spring Cloud Config Server to Local Git Repository
• Configuration for Multiple Environments in Git Repository
• Connect Limits Service to Spring Cloud Config Server
• Configuring Profiles for Limits Service
• A review of Spring Cloud Config Server

Implementing 2 Microservices with Eureka Naming Server, Ribbon and Feign

• Introduction to Currency Conversion and Currency Exchange Microservices TODO
• Setting up Currency Exchange Microservice
• Create a simple hard coded currency exchange service
• Setting up Dynamic Port in the the Response
• Configure JPA and Initialized Data
• Create a JPA Repository
• Setting up Currency Conversion Microservice
• Creating a service for currency conversion
• Invoking Currency Exchange Microservice from Currency Conversion Microservice
• Using Feign REST Client for Service Invocation
• Setting up client side load balancing with Ribbon
• Running client side load balancing with Ribbon
• Understand the need for a Naming Server
• Setting up Eureka Naming Server
• Connecting Currency Conversion Microservice to Eureka
• Connecting Currency Exchange Microservice to Eureka
• Distributing calls using Eureka and Ribbon
• A review of implementing Eureka, Ribbon and Feign

API Gateways and Distributed Tracing

• Introduction to API Gateways
• Setting up Zuul API Gateway
• Implementing Zuul Logging Filter
• Executing a request through Zuul API Gateway
• Setting up Zuul API Gateway between microservice invocations
• Introduction to Distributed Tracing
• Implementing Spring Cloud Sleuth
• Introduction to Distributed Tracing with Zipkin
• Installing Rabbit MQ
• Setting up Distributed Tracing with Zipkin
• Connecting microservices to Zipkin
• Using Zipkin UI Dashboard to trace requests

Spring Cloud Bus and Hysterix

• Understanding the need for Spring Cloud Bus
• Implementing Spring Cloud Bus
• Fault Tolerance with Hystrix

Ports

Application	Port
Limits Service	8080, 8081, ...
Spring Cloud Config Server	8888
Currency Exchange Service	8000, 8001, 8002, ..
Currency Conversion Service	8100, 8101, 8102, ...
Netflix Eureka Naming Server	8761
Netflix Zuul API Gateway Server	8765
Zipkin Distributed Tracing Server	9411

URLs

Application	URL
Limits Service	http://localhost:8080/limits POST -> http://localhost:8080/actuator/refresh
Spring Cloud Config Server	http://localhost:8888/limits-service/default http://localhost:8888/limits-service/dev
Currency Converter Service - Direct Call	http://localhost:8100/currency-converter/from/USD/to/MAD/quantity/10
Currency Converter Service - Feign	http://localhost:8100/currency-converter/from/EUR/to/MAD/quantity/10000
Currency Exchange Service	http://localhost:8000/currency-exchange/from/EUR/to/MAD http://localhost:8001/currency-exchange/from/USD/to/MAD
Eureka	http://localhost:8761/
Zuul - Currency Exchange & Exchange Services	http://localhost:8765/currency-exchange-service/currency-exchange/from/EUR/to/MAD http://localhost:8765/currency-conversion-service/currency-converter/from/USD/to/MAD/quantity/10
Zipkin	http://localhost:9411/zipkin/
Spring Cloud Bus Refresh	http://localhost:8080/bus/refresh

Zipkin Installation

Quick Start Page

• https://zipkin.io/pages/quickstart

Downloading Zipkin Jar

• https://search.maven.org/remote_content?g=io.zipkin.java&a=zipkin-server&v=LATEST&c=exec

Command to run

RABBIT_URI=amqp://localhost java -jar zipkin-server-2.5.2-exec.jar

VM Argument

-Dserver.port=8001

Commands

mkdir git-configuration-repo
cd git-configuration-repo/
git init
git add -A
git commit -m "Init commit"

Spring Cloud Configuration

spring.cloud.config.failFast=true

More Reading about Microservices

• Design and Governance of Microservices
  • https://martinfowler.com/microservices/
• 12 Factor App
  • https://12factor.net/
  • https://dzone.com/articles/the-12-factor-app-a-java-developers-perspective
• Spring Cloud
  • http://projects.spring.io/spring-cloud/