Code files

Chapter11/deploying-to-the-cloud/micro/webapp/lib/event-logger.js

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+'use strict'
+
+const { dns } = require('concordant')()
+const redis = require('redis')
+
+module.exports = eventLogger
+
+function eventLogger () {
+  const QNAME = 'eventservice'
+  var client
+
+  const endpoint = '_main._tcp.redis.micro.svc.cluster.local'
+  dns.resolve(endpoint, (err, locs) => {
+    if (err) {
+      console.error(err)
+      return
+    }
+    const { port, host } = locs[0]
+    client = redis.createClient(port, host)
+  })
+
+  function middleware (req, res, next) {
+    if (!client) {
+      console.log('client not ready, waiting 100ms')
+      setTimeout(middleware, 100, req, res, next)
+      return
+    }
+    const event = {
+      action: 'record',
+      type: 'page', 
+      url: `${req.protocol}://${req.get('host')}${req.originalUrl}`
+    }
+    client.lpush(QNAME, JSON.stringify(event), (err) => {
+      if (err) console.error(err)
+      next()
+    })
+  }
+
+  return middleware
+}