Intro

Copyright (c) 2019 Johan Vandeweerd

https://github.com/johanvandeweerd/demo

This is a small demo project to play with Spring Boot, Gradle, Docker and Datadog. It exists of two microservices: web and worker.
The web service has an HTTP endpoint and puts a message onto a Kafka topic. The worker listens on this topic and prints the content of the messages to the console.

Prerequisites

• Docker
• Docker Compose
• (trail) Datadog account
• Java 11 (optional)

Getting started

Prepare

• Replace the value of DD_API_KEY in ops/docker/datadog/docker-compose.yml with your (newly created) Datadog API key
• Create a docker network named demo

docker network create demo

Build

You can build the project using a local Java 11 or from Docker.

Build using Java

Execute the following commands from the root of the project to build the demo app and create docker images:

./gradlew dockerTag

Build in Docker

Execute the following commands from the root of the project to build the demo app and create docker images:

docker build -t demo-build ops/docker/build
docker run -it --rm \
    -v /var/run/docker.sock:/var/run/docker.sock \ 
    demo-build ./gradlew dockerTag

Run

• Start the datadog agent

(cd ops/docker/datadog ; docker-compose up -d)

• Start the kafka broker

(cd ops/docker/kafka ; docker-compose up -d)

• Start the demo application

(cd ops/docker/demo ; docker-compose up -d)

Run from IDE

When running the demo application from an IDE, make sure to

• Add the following to your /etc/hosts file

127.0.0.1   kafka datadog

• Download the Datadog java agent to the root of the project as dd-java-agent.jar
• Start the demo-web app with the following
  • VM options:
    • -javaagent:dd-java-agent.jar
  • environment variables:
    • DD_JMXFETCH_ENABLED=true
    • DD_LOGS_INJECTION=true
    • DD_SERVICE_NAME=demo-web
    • DD_TRACE_GLOBAL_TAGS=env:demo
    • SERVER_PORT=8000
    • SPRING_PROFILES_ACTIVE=local
• Start the demo-worker app with the following
  • VM options:
    • -javaagent:dd-java-agent.jar
  • environment variables:
    • DD_JMXFETCH_ENABLED=true
    • DD_LOGS_INJECTION=true
    • DD_SERVICE_NAME=demo-worker
    • DD_TRACE_GLOBAL_TAGS=env:demo
    • SPRING_PROFILES_ACTIVE=local

Test

Use your browser or favorite HTTP client to call http://localhost:8080/hello/<your-name> or use the toolbox with the following commands:

cd ops/docker/toolbox
docker build -t toolbox .
docker run -it --rm --network demo toolbox curl http://demo-web:8080/hello/<your-name>

More goodness

• Tail the logs for the web service

docker-compose logs -f demo_demo-web_1

• Tail the logs for the worker service

docker-compose logs -f demo_demo-worker_1

• Tail the logs for the datadog agent

docker-compose logs -f datadog_datadog_1

• Tail the logs for the kafka broker

docker-compose logs -f kafka_kafka_1

• Build the toolbox

cd ops/docker/toolbox
docker build -t toolbox .

• Start the toolbox. You can use ping, dig, netcat, telnet, curl or kafkacat.
  Use the following DNS names:
  • demo-web
  • demo-worker
  • kafka
  • zookeeper

docker run -it --rm --name toolbox --network demo toolbox bash 

Cavaets

Kill the gradle daemon when you experience the following error:

FAILURE: Build failed with an exception.

* What went wrong:
Execution failed for task ':demo-web:docker'.
> A problem occurred starting process 'command 'docker''