go

Go sample app

This is a sample app consisting of a basic client and server written in Go. The server listens for requests which the client makes on a timed loop.

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:

   make build
   

   This command will also update the local manifests to refer to your image location.

2. Push the local image to the Artifact Registry you created in the setup steps (if you did not create one, or are using an already created registry, make sure to set the REGISTRY_LOCATION and CONTAINER_REGISTRY variables):

   make push
   

3. Deploy the app in your cluster:

   kubectl apply -f k8s/.
   

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

4. Run the following commands to patch the app and server deployments for auto-instrumentation:

   kubectl patch deployment.apps/goshowcase-app -p '{"spec":{"template":{"metadata":{"annotations":{"instrumentation.opentelemetry.io/inject-go": "true", "instrumentation.opentelemetry.io/otel-go-auto-target-exe": "/app/main"}}}}}'
   kubectl patch deployment.apps/goshowcase-server -p '{"spec":{"template":{"metadata":{"annotations":{"instrumentation.opentelemetry.io/inject-go": "true", "instrumentation.opentelemetry.io/otel-go-auto-target-exe": "/server/main"}}}}}'
   

   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.