Add UUID to the logs per session

app.js

@@ -15,6 +15,7 @@ const { hasData } = require('./utils')
 const { addNunjucksFilters } = require('./filters')
 const csp = require('./config/csp.config')
 const csrf = require('csurf')
+const uuidv4 = require('uuid').v4
 
 // check to see if we have a custom configRoutes function
 let { configRoutes, routes, locales } = require('./config/routes.config')
@@ -78,6 +79,15 @@ app.locals.hasData = hasData
 app.locals.basedir = path.join(__dirname, './views')
 app.set('views', [path.join(__dirname, './views')])
 
+app.use(function(req, res, next) {
+  // set a unique user id per session
+  if (!req.session.id) req.session.id = uuidv4()
+  // add user id to req.locals so that the logger has access to it
+  req.locals = { id: req.session.id }
+
+  next()
+})
+
 app.routes = configRoutes(app, routes, locales)
 
 // view engine setup

config/morgan.config.js

@@ -5,7 +5,11 @@ morgan.token('version', function getSha() {
 })
 
 morgan.token('err', function getErr(req, res) {
-  return res.locals.err
+  return req.locals.err
+})
+
+morgan.token('id', function getId(req, res) {
+  return req.locals.id
 })
 
 module.exports = (function morganConfig() {
@@ -27,6 +31,7 @@ function jsonFormatDev(tokens, req, res) {
 
 function jsonFormatProduction(tokens, req, res) {
   return JSON.stringify({
+    id: tokens['id'](req, res),
     method: tokens['method'](req, res),
     url: tokens['url'](req, res),
     status: tokens['status'](req, res),

package.json

@@ -51,6 +51,7 @@
     "postcss-loader": "^3.0.0",
     "request": "^2.88.0",
     "tailwindcss": "^1.1.3",
+    "uuid": "^7.0.3",
     "webpack": "^4.42.1",
     "webpack-cli": "^3.3.11",
     "webpack-merge": "^4.2.2"