README.md

Standalone container quick start

While you can build complex multi tier application simulations with the generators for kubernetes or docker compose it is possible to use the cisco-open/app-simulator container images standalone. In this document you will find a few standalone examples that demonstrate this use case.

Table Of Contents

Java application with OpenTelemetry

If you are looking for a way to generate some sample telemetry with the OpenTelemetry Java agent, create a config.json with the following content:

{
  "endpoints": {
    "http": {
      "/my/endpoint": [
        "http://github.com/",
        "sleep,1000",
        {
          "call": "error,500,oops",
          "probability": 0.25
        }
      ]
    }
  },
  "name": "frontend",
  "type": "java"
}

In the same folder, run the app-simulator-services-java with Docker:

docker run -t -i --rm --volume ${PWD}/config.json:/config.json -p 8080:8080 ghcr.io/cisco-open/app-simulator-services-java:latest

This will start a Java based webserver listening on port 8080 for requests. Run the following command a few times:

curl -v localhost:8080/my/endpoint

You will see that 1 in 4 requests will return a 500 Server Error.

Add the OpenTelemetry Java agent to create telemetry for the service.

Stop the currently running container and download the Java agent:

https://github.com/open-telemetry/opentelemetry-java-instrumentation/releases/latest/download/opentelemetry-javaagent.jar

Restart the container with the following settings:

docker run -t -i --rm \
           --volume ${PWD}/config.json:/config.json \
           --volume ${PWD}/opentelemetry-javaagent.jar:/opt/opentelemetry-javaagent.jar \
           -e JAVA_TOOL_OPTIONS="-javaagent:/opt/opentelemetry-javaagent.jar" \
           -e OTEL_SERVICE_NAME="my-simulated-app" \
           -e OTEL_TRACES_EXPORTER=logging \
           -e OTEL_METRICS_EXPORTER=logging \
           -e OTEL_LOGS_EXPORTER=logging \
           -p 8080:8080 \
           ghcr.io/cisco-open/app-simulator-services-java:latest

This will start the Java based webserver with OpenTelemetry enabled. Re-run the previous command to send some requests:

curl -v localhost:8080/my/endpoint

The Java agent will print telemetry to the console, e.g.:

[otel.javaagent 2024-12-30 14:31:24:972 +0000] [qtp1467981309-27] INFO io.opentelemetry.exporter.logging.LoggingSpanExporter - 'GET' : bbf7fc4f97e47a2bdef475f928099d62 31baa1f78b9c2701 SERVER
[tracer: io.opentelemetry.jetty-11.0:2.11.0-alpha] AttributesMap{data={url.scheme=http, thread.name=qtp1467981309-27, network.protocol.version=1.1, network.peer.port=61224, user_agent.original=curl/8.7.1,
http.request.method=GET, server.port=8080, url.path=/my/endpoint, thread.id=27, error.type=500, server.address=localhost, client.address=172.17.0.1, http.response.status_code=500,
network.peer.address=172.17.0.1}, capacity=128, totalAddedValues=14}

As a final step, start jaeger and send traces to it via OTLP:

docker run --rm --name jaeger \
  -p 16686:16686 \
  -p 4317:4317 \
  -p 4318:4318 \
  --network app-sim \
  jaegertracing/all-in-one:1.64.0

and

docker run -t -i --rm \
           --volume ${PWD}/config.json:/config.json \
           --volume ${PWD}/opentelemetry-javaagent.jar:/opt/opentelemetry-javaagent.jar \
           -e JAVA_TOOL_OPTIONS="-javaagent:/opt/opentelemetry-javaagent.jar" \
           -e OTEL_SERVICE_NAME="my-simulated-app" \
           -e OTEL_TRACES_EXPORTER=otlp \
           -e OTEL_EXPORTER_OTLP_TRACES_ENDPOINT=http://jaeger:4318/v1/traces \
           -e OTEL_METRICS_EXPORTER=none \
           -e OTEL_LOGS_EXPORTER=none \
           -p 8080:8080 \
           --network app-sim \
           ghcr.io/cisco-open/app-simulator-services-java:latest

A span for a request that returned a 500 Server Error looks like the following in jaeger:

curl loader as base image

Like any other container image, you can use cisco-open/app-simulator container images as base images, e.g.:

FROM ghcr.io/cisco-open/app-simulator-loaders-curl:latest

WAIT=0
SLEEP=5
URLS=https://github.com/cisco-open/app-simulator

Build the docker image:

docker build -t my-load-generator .

Run your custom load generator for https://github.com/cisco-open/app-simulator:

docker run --rm -t -i my-load-generator