Spring Cloud microservices

Clone all Projects together. Remember to switch to main branch instead of being into detached head.

git clone --recurse-submodules -j8 https://github.com/nitinkc/spring-microservices.git
cd spring-microservices

git submodule init
git submodule update 

Read the Spring Modules that comprise the Spring Cloud

Diagram demonstrating the major components of Spring microservices Architecture

[test](###3. Conversion microservice)

Ports used in the project

Application	Port
Conversion microservice	8000, 8001, 8002, ..
Calculation microservice	8100, 8101, 8102, …
Netflix Eureka Naming Server	8761
Netflix Zuul API Gateway Server	8765
Zipkin Distributed Tracing Server	9411
Test Config microservice	8080, 8081, …
Spring Cloud Config Server	8888

3. Conversion microservice

Simple Spring Project that reads values from a DB and returns a conversion Factor for the consuming microservice

Group : com.microservices.learning.conversion

Artifact : conversion-service

Dependencies :

• Web
• Actuator
• dev tools
• config client
• jpa
• H2 Db

H2 DB Web Client URL : http://localhost:8000/h2-console/

4. Calculation micro service

Consumes Conversion micro service and performs x*value returned by conversion micro service operation to

Following technologies used :

• Rest template for consuming a rest microservices
• Declarative REST Client: Feign
• Ribbon Load Balancing
• Support for Eureka Naming Server (adds eureka client)

The rest calls are distributed using Ribbon & Eureka

• Zuul API Gateway integration

https://dzone.com/articles/microservices-communication-zuul-api-gateway-1

• Spring cloud sleuth : Provides a unique id to all the requests. Place the dependency to all the projects needing a unique request id
• Zipkin distributed Tracing server

Group : com.microservices.learning.calculation

Artifact : calculation-service

Dependencies :

• Web
• Actuator
• dev tools
• config client

VM Argument to run multiple instances of a microservice

	-Dserver.port=8001

5. Eureka Naming Server

Group : com.microservices.learning.eureka

Artifact : eureka-naming-server

Dependencies :

• Eureka Server
• Config Client
• Spring Boot Actuator
• Spring Boot DevTools

Access Eureka Server UI at : http://localhost:8761/

6. Zuul API Gateway

Group : com.microservices.learning.zuul

Artifact : zuul-api-gateway

Dependencies :

• Zuul
• EurekaDiscovery
• Actuator
• DevTools

7. Zipkin Distributed Tracing server

Has to be started in a terminal after starting Rabbit MQ server

• Rabbit MQ Should be installed and run

/usr/local/sbin/rabbitmq-server# Zipkin Distributed Tracing Server

* Rabbit MQ Should be installed and run
```sh
/usr/local/sbin/rabbitmq-server

• Install Zipkin Distributed Tracing Server from https://zipkin.io/pages/quickstart
• Run Zipkin server on terminal as

RABBIT_URI=amqp://localhost java -jar zipkin.jar

• Launch Zipkin server on terminal

http://localhost:9411/zipkin/

Sequence of starting the servers

1. Eureka Naming Server
   • Run the server on http://localhost:8761/
2. Zuul API Gateway
3. Command Service
   • Run 3 instances with run/debug configurations with VM Options set for ports 8001, 8002 -Dserver.port=8001
4. Query Service with H2 inMemory DB
   • Run 3 instances with run/debug configurations with VM Options set for ports 8101, 8102 -Dserver.port=8101
5. Rabbit MQ
   • On Mac Install via brew
   • Run on foreground : CONF_ENV_FILE="/usr/local/etc/rabbitmq/rabbitmq-env.conf" /usr/local/opt/rabbitmq/sbin/rabbitmq-server
   • access the portal - http://localhost:15672/ with guest/guest
6. Zipkin tracing server
   • docker run -d -p 9411:9411 openzipkin/zipkin
   • http://localhost:9411/zipkin/

Maven Dependencies

<!-- Spring Cloud Config Client -->
<dependency>
	<groupId>org.springframework.cloud</groupId>
	<artifactId>spring-cloud-starter-config</artifactId>
</dependency>
<!--Feign Support Added-->
<dependency>
	<groupId>org.springframework.cloud</groupId>
	<artifactId>spring-cloud-starter-openfeign</artifactId>
</dependency>
<!-- Ribbon Load Balancing added -->
<dependency>
	<groupId>org.springframework.cloud</groupId>
	<artifactId>spring-cloud-starter-netflix-ribbon</artifactId>
</dependency>
<!-- Client for Eureka NamingServer -->
<dependency>
	<groupId>org.springframework.cloud</groupId>
	<artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
</dependency>
<!-- Spring Cloud Sleuth -->
<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-sleuth</artifactId>
</dependency>
<!-- Zipkin Distributed Tracing Server added -->
<dependency>
	<groupId>org.springframework.cloud</groupId>
	<artifactId>spring-cloud-starter-zipkin</artifactId>
</dependency>
<!-- Rabbit Messaging Support added -->
<dependency>
	<groupId>org.springframework.amqp</groupId>
	<artifactId>spring-rabbit</artifactId>
</dependency>