Overview

This application is a very basic Spring Boot 2.0 application. It has configuration and features designed to make it discoverable in a service mesh. It shows how to register the application with a locally running Consul agent on port 8500.

To do this, the application makes use of the Spring Cloud Consul project. It is enabled via a Maven depencency. When the application starts it registers itself with Consul -giving it a unique number after the app name.

This project also makes use of the Spring Actuator project. It is enabled via Maven dependency. This exposes a 'health' endpoint that Consul can use to detect if the application is running.

Build executable JAR called spring-boot-http and place in /target folder

mvn clean && mvn package

Build docker image

Run this in the main project folder 'spring-boot-http')

Look in the Dockerfile to see the contents of this image. It's based on OpenDJK 8

docker build -t spring-boot-http .

Run docker container in the background (detached), exposing it on port 8080

docker run -d -p 8080:8080 --name spring-boot-http spring-boot-http

If you need to rebuild your running docker image/container and re-deploy it in docker

Run this in the main project folder 'spring-boot-http'

docker stop spring-boot-http && docker rm spring-boot-http
docker build -t spring-boot-http .
docker run -d -p 8080:8080 -p 8443:8443 --name spring-boot-http spring-boot-http

Test in Browser.

You should see 'Echo: Hello World returned'

http://localhost:8080/echo/?msg=Hello%20World

Test with curl

curl http://localhost:8080/echo/?msg=Hello%20World

Start Consul container, referring this service configuration

docker stop consul-agent && docker rm consul-agent
docker run --rm -d -v$(pwd)/consul-services.hcl:/etc/consul/consul-services.hcl \
  --network host --name consul-agent consul:1.3.0 \
  agent -dev -config-file /etc/consul/consul-services.hcl

Inspect logs of consul-agent

docker logs -f consul-agent

Start 'echo' service. This is the spring-boot-http application. It must be configured to proxy requests to the side-car Envoy proxy

docker stop spring-boot-http && docker rm spring-boot-http
docker run \
-it \
--rm \
-p 8080:8080 \
--name spring-boot-http \
spring-boot-http

Start Envoy side-car proxies for both client (curl) and echo service (spring-boot-http app)

docker stop echo-proxy && docker rm echo-proxy
docker stop client-proxy && docker rm client-proxy

docker run --rm -d --network host --name echo-proxy \
  consul-envoy -sidecar-for echo

docker run --rm -d --network host --name client-proxy \
  consul-envoy -sidecar-for client -admin-bind localhost:19001

Now invoke curl (client) which should use it's side-car proxy to send request to the echo/spring-boot service

We need to run the curl command as in a Docker container since we wired every other container together using the docker '--network host' argument. This means port 9191 is NOT exposed outside of the Docker network

docker run --rm --network host appropriate/curl -s http://localhost:9191/echo?msg=Hello%20Andrew2