OpenTelemetry Spanner Sample Application

This is a sample application demonstrating a bug in the OpenTelemetry instrumentation with Cloud Spanner using the Spanner emulator.

Prerequisites

• Node 16+
• Cloud Spanner Emulator - Setup Instructions

Setup

1. Start the Spanner emulator:

docker pull gcr.io/cloud-spanner-emulator/emulator
docker run -p 9020:9020 gcr.io/cloud-spanner-emulator/emulator

2. Install dependencies:

npm install

3. Start the application:

npm start

Example Usage

Basic query example:

curl http://localhost:8080/

Tracing

The application is instrumented with OpenTelemetry Node SDK and outputs traces to the console. Each request will generate a trace with multiple spans showing the Spanner operations.

Example trace output:

{
  "traceId": "abc123...",
  "spanId": "def456...",
  "name": "CloudSpanner.executeStreamingSql",
  "attributes": {
    "db.system": "spanner",
    "db.name": "otel-spanner-test-database"
  }
}

Environment Variables

• PORT - Server port (default: 8080)

Notes

This application uses the Spanner emulator for local development. For production use, you'll need to configure actual Google Cloud credentials and update the Spanner connection settings.