Code files

Chapter10/service-discovery-with-dns/micro/webapp/routes/add.js

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+'use strict'
+
+const { Router } = require('express')
+const restify = require('restify')
+const { dns } = require('concordant')()
+const router = Router()
+var clients
+
+router.get('/', function (req, res) {
+  res.render('add', { first: 0, second: 0, result: 0 })
+})
+
+router.post('/calculate', resolve, respond)
+
+function resolve (req, res, next) {
+  if (clients) {
+    next()
+    return
+  }
+  const adderservice = `_main._tcp.adderservice.micro.svc.cluster.local`
+  const auditservice = `_main._tcp.auditservice.micro.svc.cluster.local`
+  dns.resolve(adderservice, (err, locs) => {
+    if (err) {
+      next(err)
+      return
+    }
+    const { host, port } = locs[0]
+    const adder = `${host}:${port}`
+    dns.resolve(auditservice, (err, locs) => {
+      if (err) { 
+        next(err)
+        return
+      }
+      const { host, port } = locs[0]
+      const audit = `${host}:${port}`
+      clients = { 
+        adder: restify.createJSONClient({url: `http://${adder}`}), 
+        audit: restify.createJSONClient({url: `http://${audit}`})
+      }
+      next()
+    })
+  })
+}
+
+function respond (req, res, next) {
+  const { first, second } = req.body
+  clients.adder.get(
+    `/add/${first}/${second}`,
+    (err, svcReq, svcRes, data) => {
+      if (err) {
+        next(err)
+        return
+      }
+
+      const { result } = data
+      clients.audit.post('/append', {
+        calc: first + '+' + second,
+        calcResult: result
+      }, (err) => {
+        if (err) console.error(err)
+      })
+      
+      res.render('add', { first, second, result })
+    }
+  )
+}
+
+module.exports = router