mnr-transaction-id

Express middleware for tracking transactions in microservices architecture.

You may not need it!

This is a custom, highly opinionated solution aimed at code reuse for a few private projects.

Installation

$ npm install --save mnr-transaction-id

Usage Example

JavaScript:

const mnrTransactionId = require('mnr-transaction-id');

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

app.get('/my-endpoint', (req, res) => {
  console.log(req.transactionId);
});

TypeScript:

import mnrTransactionId, { RequestWithTransactionId } from 'mnr-transaction-id';

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

app.get('/my-endpoint', (req, res) => {
  console.log((req as RequestWithTransactionId).transactionId);
});

What It Does

1. Add req.transactionId either from request's x-transaction-id HTTP header, or newly generated UUID if there is no such a header. The most obvious use case for req.transactionId is using it in logs.

2. Add x-transaction-id HTTP header to response. The value is taken from req.transactionId.