java

Java sample app

This sample app runs a server "service" that listens for requests from a client "app" running as a CronJob.

Prerequisites

• OpenTelemetry Operator installed in your cluster
• Artifact Registry set up in your GCP project (see the main README.md)
• An OpenTelemetryCollector object already created in the current namespace, such as the sample collector-config.yaml from the main README
• An Instrumentation object already created in the current namespace, such as the sample instrumentation.yaml from the main README

Running

1. Build the sample app and service:

   make build
   

   This command will also push the app's images to the Artifact Registry you set up in the Prerequisites. It also updates the local manifests to refer to your image registry.

2. Deploy the apps in your cluster:

   kubectl apply -f k8s/.
   

   If you want to run the sample app in a specific namespace, pass -n <your-namespace>.

3. Run the following commands to patch the app CronJob and service Deployment for auto-instrumentation:

   kubectl patch deployment.apps/javashowcase-service -p '{"spec":{"template":{"metadata":{"annotations":{"instrumentation.opentelemetry.io/inject-java": "true"}}}}}'
   kubectl patch cronjob.batch/javashowcase-app -p '{"spec":{"jobTemplate":{"spec":{"template":{"metadata":{"annotations":{"instrumentation.opentelemetry.io/inject-java": "true"}}}}}}}'
   

   These commands will use the Instrumentation created as part of the Prerequisites.

View your Spans

To stream logs from the otel-collector, which will include spans from this sample application, run:

kubectl logs deployment/otel-collector -f

Alternatively, follow the cloud-trace recipe to view your spans in Google Cloud Trace.