Simplified Datadog Java APM Example

A very simple Java application using Datadog APM w/ the Datadog dd-trace-api as described in the Datadog Java APM docs.

This repo leverages Docker for ease of use.

Noteworthy

• This small project is for demonstration purposes only.
• It does not make use any container orchestrator.
• It's original intent was to be used on a developer's local machine.
• It is not production grade.

Prerequisites

• Install Java OpenJDK for your platform
• Install Docker for your platform

Send APM Metrics to Datadog

Run the Datadog Dockerized Agent

• Run to build the image: docker build -t dd-agent ./agent/
• Run the following, replacing {your_api_key_here} with your own DD API key.

  docker run -d --rm --name dd-agent \
    -v /var/run/docker.sock:/var/run/docker.sock:ro \
    -v /proc/:/host/proc/:ro \
    -v /sys/fs/cgroup/:/host/sys/fs/cgroup:ro \
    -e API_KEY={your_api_key_here} \
    -e DD_APM_ENABLED=true \
    -p 8126:8126/tcp \
    -e SD_BACKEND=docker \
    -e LOG_LEVEL=DEBUG \
    -e DD_LOGS_STDOUT=yes \
    -e DD_PROCESS_AGENT_ENABLED=true \
    dd-agent
  

Run the Java example

• Run ./gradlew build (or gradlew.bat if on windows)
• Set an environment variable with the DD docker agent IP:

    DD_AGENT_IP_ADDR=`docker inspect -f '{{range .NetworkSettings.Networks}}{{.IPAddress}}{{end}}' dd-agent`
  

• Run to build the docker image: docker build -t dd-java-apm --build-arg DD_AGENT_IP=$DD_AGENT_IP_ADDR .
• Run to start the container:

  docker run -d -p 8081:8080 --rm --name dd-java-apm dd-java-apm \
  -e TAGS=host:dd-java-apm-demo-openjdk,env:demo
  

Additional Docker commands

• Run to see the containers running: docker ps
• Run to see container logs: docker logs dd-java-apm
• Run to get to bash prompt for the container: docker exec -it dd-java-apm /bin/bash
• Run to stop the container: docker stop dd-java-apm
• Run to remove the container: docker rm dd-java-apm

See APM in Datadog

• Hit these web urls locally to generate some APM metrics and traces:
  • http://localhost:8081
  • http://localhost:8081/sleepy
    • Noteworthy
      • As an unauthenticated GitHub request, you may see:

        {
          "message": "API rate limit exceeded for 76.97.244.208. (But here's the good news: Authenticated requests get a higher rate limit. Check out the documentation for more details.)",
          "documentation_url": "https://developer.github.com/v3/#rate-limiting"
        }
        

        Pretty quickly when executing /lookup -- this will result in a 500 from this application since it isn't doing any proper exception handling
• Visit Datadog APM env:demo and the dd-java-apm-example-openjdk service should be listed.
  • The "home" (e.g. http://localhost:8081/) request mapping should result in a flame graph that looks like: