Spring

The purpose of this project is to show an example on how to setup and configure spring services in a cloud infrastructure.

Technologies

• Spring Cloud Config for configuration
• Spring Cloud Netflix Eureka for service discovery
• Spring Cloud Netflix Zuul as API gateway
• Spring Cloud Netflix Feign as declarative web client
• Spring Cloud Netflix Ribbon as client side loadbalancer
• Spring Cloud Netflix Hystrix for fault tolerance
• Spring Boot Actuator for config refresh
• Spring Cloud Bus for automatic config refresh using rabbitmq
• Spring Cloud Sleuth for tracing
• Spring Cloud Zipkin for tracing

Scenario

This is a fictional scenario which does not really make much sense.

It contains a user service which provides a REST-Endpoint to return user information in XML format.

It also contains a user transformation service which provides a REST-Endpoint to call the user service and transform the XML result into JSON.

The users are returned ordered by their first name, last name or age. This is configured using the configuration service (As I said, this does not make much sense, it is just an example and it focuses on the cloud infrastructure).

Services

Rabbit MQ

host: localhost
ports: 
  - 5672    # rabbit mq
  - 15672   # rabbit mq management

Use branch kafka if you want to use Apache Kafka instead of Rabbit MQ.

Spring Cloud Config Server

host: localhost
port: 8888

In this project it uses: https://github.com/LybrialsGit/config-repository.git as config repository. If you want to change that you need to adjust the application.yml file in the config-server project to point to a different repository.

Spring Cloud Eureka Server

host: locahost
port: 8761

Spring Cloud Zuul Gateway

host: localhost
port: 8765

User-Service

host: localhost
ports:
  - 8000  # instance 1
  - 8001  # instance 2
  - 8002  # instance 3

User-Transformation-Service

host: localhost
port: 8100

Uses Feign to call the user service via Zuul API gateway and Ribbon for client side load balancing. You can see in the logs of the user services which of the three user service instances is getting called (attach to docker logs).

Zipkin Server

host: localhost
port: 9411

Starting the services

docker-compose -f docker-compose-cloud.yml up -d --build
docker-compose -f docker-compose-zipkin.yml up -d --build
docker-compose -f docker-compose-services.yml up -d --build

Wait in between until the services are started.

If you want to see the logs remove the parameter -d (for detached) or attach manually using: docker-compose logs -f <container-name>.

Updating the configuration

If you want to change the configuration first commit and push your changes to the configuration repository. After that you can either update each services config individually by making a POST to each service, for example:

http://localhost:8000/actuator/refresh

Or you can make a bus refresh to update the configuration of all services at once:

http://localhost:8888/actuator/bus-refresh

The bus-refresh endpoint can be called on any service. It will automatically trigger the configuration refresh of all services (using rabbitmq and spring cloud bus).

Using Zuul gateway

Call:

http://localhost:8765/user-service/users
http://localhost:8765/user-transformation-service/users

Trace requests

Call:

http://localhost:9411

And search for trace ID's.