Microservices with Consul, HAProxy and Spring Boot

Sample Store application composed by 3 microservices.

• Core Service (base-service-[api|client|starter])
  Framework to provide auto-configuration to Consul, Jersey and JAX-RS Clients. Besides some common functionalities such as interceptors for exceptions, base classes for messages and generic endpoints.
• Promotion Service (promotion-[api|client|service])
• Product Service (product-[api|client|service])
• Cart Service (cart-[api|client|service])
• Consul as Service Discovery and Configuration Storage.
• HAProxy that use Consul Template to update the instances.

API - Project that contains JAX-RS contracts and Models defined using JSON Schema
CLIENT - Spring Boot library that auto configure a RestClient instance that use the JAX-RS contract.
SERVICE - Spring Boot application that implements the JAX-RS.

Presentation

https://adolfojunior.github.io/ac4talk-store-presentation/#/

Build

Get the project:

git clone https://github.com/adolfojunior/ac4talk-store.git
cd ac4talk-store

We will need Docker to run Consul/HAProxy and all the services.

To build the project you need Java 8 (You can use Docker to not mess with your environment)

Example of a build using docker:

docker run -it --rm -v $(pwd):/app -w /app openjdk:8 ./gradlew --version

Starting all the services

# configure project to your IDE
./gradlew cleanEclipse eclipse

# build it!
./gradlew clean build

# run each searvice
./gradlew :promotion-service:bootRun
./gradlew :product-service:bootRun
./gradlew :cart-service:bootRun

Running everything on Docker 🐳

Just do it docker-compose up -d

To bring everething down, we just need to do docker-compose down

Is possible to scale up some services. Just do docker-compose scale $SERVICE=N

Running it step-by-step

We are using docker-compose to make our live easier!

Bringing up Consul :squirrel:

Consul provide an easy way to let services register themselves and to discovery other services via a DNS or HTTP interface.

docker-compose up -d consul
# Follow logs
docker-compose logs -f consul

Access the Consul Web UI (http://consul.lvh.me:8500/ui)

Bringing up HAProxy 🚦

HAProxy is a very fast and reliable solution for high availability, load balancing, and proxying for TCP and HTTP-based applications.

We will use Consul Template to update the HAProxy configuration everytime a new service register/deregister itself.

As part of the configuration, each instance registered on Consul will provide Tags that will be used as subdomains.

docker-compose up -d haproxy
# Follow logs
docker-compose logs -f haproxy

Bringing up all the services 👾

docker-compose up -d promotion product cart
# looking at the logs
docker-compose logs -f ${SERVICE}
# accessing the instance
docker-compose exec ${SERVICE} sh

Testing

• Check if consul-template is updating the config

docker-compose exec haproxy cat /haproxy/haproxy.cfg

• Check consul DNS

docker-compose run service-test ping consul.service.consul

• Check all the RESTful Endpoints

curl -X GET "http://promotion-service.lvh.me/api/promotion/PROM20"

curl -X GET "http://product-service.lvh.me/api/product/all"
curl -X GET "http://product-service.lvh.me/api/product/p1"

curl -X GET "http://cart-service.lvh.me/api/cart"

curl -X POST "http://cart-service.lvh.me/api/cart/{id}/{version}/apply-promotion" \
  -H "Content-Type: application/json" \
  -d '{ "promotionCode": "PROM20" }'

curl -X POST "http://cart-service.lvh.me/api/cart/{id}/{version}/apply-items" \
  -H "Content-Type: application/json" \
  -d '{ "items": [{ "productId": "p1", "qtd": 1 }] }'

References:

• Spring Boot
• Spring Cloud Consul
• Consul
• Consul Template
• HAProxy
• Docker
• Docker Compose
• JSON Schema