talk/middleware/trace.js

const { HTTP_X_REQUEST_ID } = require('../config');
const uuid = require('uuid/v1');

// Trace middleware attaches a request id to each incoming request.
module.exports = HTTP_X_REQUEST_ID
  ? (req, res, next) => {
      req.id = req.get(HTTP_X_REQUEST_ID) || uuid();

      // Add the context ID to the request as an HTTP header.
      res.set('X-Talk-Trace-ID', req.id);

      next();
    }
  : (req, res, next) => {
      req.id = uuid();

      // Add the context ID to the request as an HTTP header.
      res.set('X-Talk-Trace-ID', req.id);

      next();
    };