OTel instrumentation.js file used in the blog post https://rudimartinsen.com/2025/07/27/otel-instrumenting-app/

instrumentation.js

/*instrumentation.js*/
// Require dependencies
const opentelemetry = require('@opentelemetry/api');
const { NodeSDK } = require('@opentelemetry/sdk-node');
const {
    OTLPTraceExporter,
  } = require('@opentelemetry/exporter-trace-otlp-proto');
const {
  getNodeAutoInstrumentations,
} = require('@opentelemetry/auto-instrumentations-node');
const {
    OTLPMetricExporter,
  } = require('@opentelemetry/exporter-metrics-otlp-proto');
const {
  PeriodicExportingMetricReader,
} = require('@opentelemetry/sdk-metrics');
const { resourceFromAttributes } = require('@opentelemetry/resources');
const { LoggerProvider, BatchLogRecordProcessor } = require('@opentelemetry/sdk-logs');
const { OTLPLogExporter } = require('@opentelemetry/exporter-logs-otlp-proto');
const logsAPI = require('@opentelemetry/api-logs');

const logExporter = new OTLPLogExporter({
    url: process.env.OTLP_LOG_EXPORTER_URL || 'http://localhost:4318/v1/logs',
    headers: {
      'Content-Type': 'application/x-protobuf',
    },
  });

// Create a LoggerProvider
const loggerProvider = new LoggerProvider({
    resource: resourceFromAttributes({
      'service.name': process.env.OTEL_SERVICE_NAME || 'my-app',
      'service.version': process.env.APP_VERSION || '0.1.0',
      'service.namespace': process.env.APP_NAMESPACE || 'my-namespace'
    }),
    processors: [new BatchLogRecordProcessor(logExporter)],
});

// Register the provider globally
logsAPI.logs.setGlobalLoggerProvider(loggerProvider);

const sdk = new NodeSDK({
  traceExporter: new OTLPTraceExporter({
    url: process.env.OTLP_TRACE_EXPORTER_URL || 'http://localhost:4318/v1/traces', // Default to localhost if env variable is not set
    headers: {
      'Content-Type': 'application/x-protobuf',
    },
  }),
  metricReader: new PeriodicExportingMetricReader({
    exporter: new OTLPMetricExporter({
      url: process.env.OTLP_METRIC_EXPORTER_URL || 'http://localhost:4318/v1/metrics', // Default to localhost if env variable is not set
      headers: {
        'Content-Type': 'application/x-protobuf',
      },
    }),
  }),
  instrumentations: [getNodeAutoInstrumentations()],
});
console.log('Starting OpenTelemetry SDK...');
sdk.start();