Node.js Winston

"use strict";

const { trace } = require("@opentelemetry/api");
const { NodeSDK } = require("@opentelemetry/sdk-node");
const { BatchLogRecordProcessor } = require("@opentelemetry/sdk-logs");
const { OTLPLogExporter } = require("@opentelemetry/exporter-logs-otlp-grpc");
const { WinstonInstrumentation } = require("@opentelemetry/instrumentation-winston");
const { resourceFromAttributes } = require("@opentelemetry/resources");
const { ATTR_SERVICE_NAME } = require("@opentelemetry/semantic-conventions");

const sleep = (ms) => new Promise((resolve) => setTimeout(resolve, ms));

const endpoint =
  process.env.OTEL_EXPORTER_OTLP_LOGS_ENDPOINT ||
  process.env.OTEL_EXPORTER_OTLP_ENDPOINT ||
  "http://localhost:4317";

async function main() {
  const sdk = new NodeSDK({
    resource: resourceFromAttributes({
      [ATTR_SERVICE_NAME]: process.env.OTEL_SERVICE_NAME || "winston-otel-sample",
      "cx.application.name": process.env.CORALOGIX_APPLICATION || "winston-otel-app",
      "cx.subsystem.name": process.env.CORALOGIX_SUBSYSTEM || "worker",
    }),
    logRecordProcessors: [new BatchLogRecordProcessor(new OTLPLogExporter({ url: endpoint }))],
    instrumentations: [new WinstonInstrumentation()],
  });

  await sdk.start();

  // Keep winston require after SDK start so instrumentation patches it.
  const winston = require("winston");
  const logger = winston.createLogger({
    level: process.env.LOG_LEVEL || "info",
    format: winston.format.combine(winston.format.timestamp(), winston.format.json()),
    defaultMeta: {
      component: "winston-otel-example",
      environment: process.env.NODE_ENV || "local",
    },
    transports: [new winston.transports.Console()],
  });

  logger.info("hello winston with OpenTelemetry");

  const tracer = trace.getTracer("winston-otel-example");
  tracer.startActiveSpan("manual-span", (span) => {
    logger.warn("winston log with trace correlation");
    span.end();
  });

  // Give batch processor a moment before shutdown flush.
  await sleep(1500);
  try {
    await sdk.shutdown();
  } catch (err) {
    console.error("Shutdown completed with exporter error:", err.message || err);
  }
  console.log("Done: flush + shutdown completed");
}

main().catch((err) => {
  console.error("Application failed:", err);
  process.exit(1);
});