https://rcoedo.com/blog/2019/11/14/continuation-local-storage-for-easy-context-passing-in-node-js

cls-hooked-create-namespace.js

const { createNamespace } = require("cls-hooked");

const ns = createNamespace("myApp");

cls-hooked-express-middleware.js

const requestIdMiddleware = (req, res, next) => {
  ns.run(() => {
    ns.set("requestId", uuid());
    next();
  });
};

cls-hooked-express-server.js

const express = require("express");
const { createNamespace } = require("cls-hooked");
const uuid = require("uuid/v4");

const ns = createNamespace("myApp");
const requestIdMiddleware = (req, res, next) => {
  ns.run(() => {
    ns.set("requestId", uuid());
    next();
  });
};

const app = express();
app.use(requestIdMiddleware);

app.get("/", (req, res) => {
  console.log(`[${ns.get("requestId")}] request received`);
  res.send("It works!");
});

const port = process.env.PORT || 3000;
app.listen(port, () => console.log(`Express server listening on port ${port}`));

Examples for "Continuation Local Storage for Easy Context Passing in Node.js"

This gist contains the examples for the article "Continuation Local Storage for Easy Context Passing in Node.js".

- https://medium.com/trabe/continuation-local-storage-for-easy-context-passing-in-node-js-2461c2120284
- https://rcoedo.com/blog/2019/11/14/continuation-local-storage-for-easy-context-passing-in-node-js