🔊[e2e] output server response in logs (#226)

* 🔊[e2e] output server response in logs

* 👌 document implementation

test/server/fake-backend.js

@@ -7,19 +7,19 @@ module.exports = (app) => {
     req.body.split('\n').forEach((log) => logs.push(JSON.parse(log)))
     res.send('ok')
   })
-  app.get('/logs', (req, res) => res.send(logs))
+  app.get('/logs', (req, res) => send(res, logs))
 
   app.post('/rum', (req, res) => {
     req.body.split('\n').forEach((rumEvent) => rumEvents.push(JSON.parse(rumEvent)))
     res.send('ok')
   })
-  app.get('/rum', (req, res) => res.send(rumEvents))
+  app.get('/rum', (req, res) => send(res, rumEvents))
 
   app.post('/monitoring', (req, res) => {
     monitoring.push(JSON.parse(req.body))
     res.send('ok')
   })
-  app.get('/monitoring', (req, res) => res.send(monitoring))
+  app.get('/monitoring', (req, res) => send(res, monitoring))
 
   app.get('/reset', (req, res) => {
     logs = []
@@ -36,3 +36,9 @@ module.exports = (app) => {
     res.send('ok')
   })
 }
+
+function send(res, data) {
+  // add response content to res object for logging
+  res.body = JSON.stringify(data)
+  res.send(data)
+}

test/server/server.js

@@ -23,7 +23,7 @@ if (process.env.ENV === 'development') {
   app.use(middleware(webpack(withBuildEnv(logsConfig(null, { mode: 'development' })))))
 } else {
   // e2e tests
-  morgan.token('body', (req) => hasValidBody(req) && `\n${req.body}`)
+  morgan.token('body', (req, res) => extractBody(req, res))
   const stream = fs.createWriteStream(path.join(__dirname, 'test-server.log'))
   app.use(morgan(':method :url :body', { stream }))
   app.use(express.static(path.join(__dirname, '../../packages/logs/bundle')))
@@ -53,6 +53,15 @@ function withBuildEnv(webpackConf) {
   return webpackConf
 }
 
-function hasValidBody(req) {
-  return req.body && JSON.stringify(req.body) !== '{}'
+function extractBody(req, res) {
+  if (isValidBody(req.body)) {
+    return `\n${req.body}`
+  }
+  if (isValidBody(res.body)) {
+    return `\n${res.body}`
+  }
+}
+
+function isValidBody(body) {
+  return body && JSON.stringify(body) !== '{}'
 }