traceapm/src/init.js

SDK for OpenTelemetry auto-instrumentation and OTLP export for Node.js apps.

const { NodeSDK } = require('@opentelemetry/sdk-node');
const { getNodeAutoInstrumentations } = require('@opentelemetry/auto-instrumentations-node');
const { OTLPTraceExporter } = require('@opentelemetry/exporter-trace-otlp-http');
const { OTLPMetricExporter } = require('@opentelemetry/exporter-metrics-otlp-http');
const { PeriodicExportingMetricReader } = require('@opentelemetry/sdk-metrics');
const { Resource } = require('@opentelemetry/resources');
const { validateConfig } = require('../utils/validate');
const logger = require('../utils/logger');

// Modularized features
const { initAutoLogger } = require('./autoLogger');
const { getProxyAgent } = require('./proxy');
const { setupGrpcExporter } = require('./grpcExporter');

/**
 * Express middleware to log every API hit (method and URL)
 */
function apiLogger(req, res, next) {
  logger.info(`API hit: ${req.method} ${req.originalUrl}`);
  next();
}

// Initialize auto-logging at startup
initAutoLogger();

/**
 * Initializes distributed tracing and metrics for your Node.js application.
 *
 * @param config Configuration object
 * @param config.serviceName Name of your service (default: 'my-service')
 * @param config.endpoint Collector endpoint (default: 'http://localhost:4318')
 * @param config.attributes Additional resource attributes (default: {})
 *
 * @example
 *   import { init } from 'traceapm';
 *   init({
 *     serviceName: 'my-service',
 *     endpoint: 'http://localhost:4318',
 *     attributes: { 'deployment.environment': 'dev' },
 *   });
 */
function init({
  serviceName = 'my-service',
  endpoint = 'http://localhost:4318',
  attributes = {},
} = {}) {
  try {
    validateConfig({ serviceName, endpoint, attributes });
    const traceExporter = new OTLPTraceExporter({ url: `${endpoint}/v1/traces` });
    const metricExporter = new OTLPMetricExporter({ url: `${endpoint}/v1/metrics` });
    const sdk = new NodeSDK({
      resource: new Resource({ 'service.name': serviceName, ...attributes }),
      traceExporter,
      metricReader: new PeriodicExportingMetricReader({
        exporter: metricExporter,
        exportIntervalMillis: 1000,
      }),
      instrumentations: [getNodeAutoInstrumentations()],
    });
    sdk.start();
    logger.info(`[traceapm] Initialized for service: ${serviceName}`);
    return {
      sdk,
      apiLogger,
      setupGrpcExporter, // Only if you want to support gRPC export
      getProxyAgent
    };
  } catch (err) {
    logger.error(`[traceapm] Initialization error: ${err.message}`);
    throw err;
  }
}

module.exports = { init };