Spring Cloud Microservice PoC

This is a PoC that show how different technologies interact. Build on top of Dalston.RELEASE train

Spring cloud libraries used:

• Spring Cloud Feign
• Spring Cloud Eureka
• Spring Cloud Config server
• Zuul gateway
• Spring Authorization Server
• Spring Cloud Hystrix
• Spring Cloud Sleuth
• Zipkin
• Spring Boot Admin

Starting Application

//TODO add picture

//TODO add run priority (basically just say Configuration server must be first :)

//import spring-cloud.postman_collection.json into postman and try it yourself

Configuration server

We use configuration-first approach. This means we must run @ConfigurationServer before running any other microservice.

To get configuration for spring-application-name=HELLO_SERVICE and profile=DEVELOPMENT we only need to call URL GET=http://localhost:9009/HELLO_SERVICE/DEVELOPMENT

Microservices must have at minimal dependency in pom.xml:

        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-config</artifactId>
        </dependency>

And these two properties set in bootstrap.properties:

spring.application.name=${microservice-name}
spring.cloud.config.uri=http://localhost:9009

Eureka server

To see all registered microservices call GET=localhost:8761.

If we want to run multiple instances of particular microservice we must uncomment

eureka.instance.instance-id=${spring.application.name}:${vcap.application.instance_id:${spring.application.instance_id:${random.value}}}

This is commented because logic for handling dead microservices is by default quite complex and I didn't put much thought into it. If this is commented out new service will replace old one and there will be no dead microservices lingering in the background.

Services that want to register with Eureka must have configuration annotated with @EnableEurekaClient

Zuul gateway

All Client calls should go through localhost:8080.

If microservice name is=HELLO_MICROSERVICE then we call localhost:8080/HELLO_MICROSERVICE

All eureka registered services can be called for now.

Authorization server

Security is stateless and OAUTH2 JWT compliant. Other services validate token by getting public key from @AuthorizationServer

Services secured with @AuthorizationServer must have at minimal annotation @EnableResourceServer and link to public key (for example security.oauth2.resource.jwt.key-uri=http://localhost:8081/oauth/token_key)

Monitoring

you must have rabbitMQ installed with default settings.

go to http://localhost:8079/hystrix

write url http://localhost:8989/turbine.stream

watch how requests play out.

tracing

//TODO stop running nvidia service

run /zipkin-web/zipkin-web.sh

go to http://localhost:9412

spring boot admin

go to http://localhost:8078/ explore :=)