Code files

Chapter10/service-discovery-with-dns/micro/auditservice/index.js

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+'use strict'
+
+const wiring = require('./wiring')
+const service = require('./service')()
+
+wiring(service)

Chapter10/service-discovery-with-dns/micro/auditservice/package.json

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+{
+  "name": "auditservice",
+  "version": "1.0.0",
+  "description": "",
+  "main": "index.js",
+  "scripts": {
+    "test": "echo \"Error: no test specified\" && exit 1"
+  },
+  "keywords": [],
+  "author": "Peter Elger",
+  "license": "ISC",
+  "dependencies": {
+    "concordant": "^0.2.1",
+    "mongo": "^0.1.0",
+    "restify": "^4.3.0"
+  }
+}

Chapter10/service-discovery-with-dns/micro/auditservice/service.js

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+'use strict'
+
+const { MongoClient } = require('mongodb')
+const { dns } = require('concordant')()
+
+module.exports = service 
+
+function service () {
+
+  var db
+
+  setup()
+  
+  function setup () {
+    const mongo = '_main._tcp.mongo.micro.svc.cluster.local'
+
+    dns.resolve(mongo, (err, locs) => {
+      if (err) { 
+        console.error(err)
+        return
+      }
+      const { host, port } = locs[0]
+      const url = `mongodb://${host}:${port}/audit`
+      MongoClient.connect(url, (err, client) => {
+        if (err) { 
+          console.log('failed to connect to MongoDB retrying in 100ms')
+          setTimeout(setup, 100)
+          return
+        }
+        db = client
+        db.on('close', () => db = null)
+      }) 
+    })
+  }
+
+  function append (args, cb) {
+    if (!db) {
+      cb(Error('No database connection'))
+      return
+    }
+    const audit = db.collection('audit')
+    const data = { 
+      ts: Date.now(),
+      calc: args.calc,
+      result: args.calcResult 
+    }
+
+    audit.insert(data, (err, result) => {
+      if (err) {
+        cb(err)
+        return
+      }
+      cb(null, {result: result.toString()})
+    })
+  }
+
+  function list (args, cb) {
+    if (!db) {
+      cb(Error('No database connection'))
+      return
+    }
+    const audit = db.collection('audit')
+    audit.find({}, {limit: 10}).toArray((err, docs) => {
+      if (err) {
+        cb(err)
+        return
+      }
+      cb(null, {list: docs})
+    })
+  }
+
+  return { append, list }
+}
+

Chapter10/service-discovery-with-dns/micro/auditservice/wiring.js

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+'use strict'
+
+const restify = require('restify')
+const { AUDITSERVICE_SERVICE_PORT } = process.env
+
+module.exports = wiring 
+
+function wiring (service) {
+  const server = restify.createServer()
+
+  server.use(restify.bodyParser())
+
+  server.post('/append', (req, res, next) => {
+    service.append(req.params, (err, result) => {
+      if (err) { 
+        res.send(err) 
+        return
+      }
+      res.send(result)
+      next()
+    })
+  })
+
+  server.get('/list', (req, res, next) => {
+    service.list(req.params, (err, result) => {
+      if (err) { 
+        res.send(err)
+        return 
+      }
+      res.send(200, result)
+      next()
+    })
+  })
+
+  server.listen(AUDITSERVICE_SERVICE_PORT, '0.0.0.0', () => {
+    console.log('%s listening at %s', server.name, server.url)
+  })
+}
+