Code files

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

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

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

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+{
+  "name": "adderservice",
+  "version": "1.0.0",
+  "description": "",
+  "main": "index.js",
+  "scripts": {
+    "test": "tap test"
+  },
+  "keywords": [],
+  "author": "Peter Elger",
+  "license": "ISC",
+  "dependencies": {
+    "restify": "^4.3.0"
+  },
+  "devDependencies": {
+    "tap": "^10.3.1"
+  }
+}

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

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+'use strict'
+
+module.exports = service
+
+function service () {
+  function add (args, cb) {
+    const {first, second} = args
+    const result = (parseInt(first, 10) + parseInt(second, 10))
+    cb(null, {result: result.toString()})
+  }
+
+  return { add }
+}

Chapter10/service-discovery-with-dns/micro/adderservice/test/index.js

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+'use strict'
+
+const {test} = require('tap')
+const service = require('../service')()
+
+test('test add', (t) => {
+  t.plan(2)
+
+  service.add({first: 1, second: 2}, (err, answer) => {
+    t.error(err)
+    t.same(answer, {result: 3})
+  })
+})

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

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

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

@@ -0,0 +1,17 @@
+{
+  "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)
+  })
+}
+

Chapter10/service-discovery-with-dns/micro/fuge/fuge.yml

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+fuge_global:
+  dns_enabled: true
+  dns_host: 127.0.0.1
+  dns_port: 53053
+  dns_suffix: svc.cluster.local
+  dns_namespace: micro
+  tail: true
+  monitor: true
+  monitor_excludes:
+    - '**/node_modules/**'
+    - '**/.git/**'
+    - '*.log'
+adderservice:
+  type: process
+  path: ../adderservice
+  run: node index.js
+  ports:
+    - main=8080
+webapp:
+  type: process
+  path: ../webapp
+  run: npm start
+  ports:
+    - main=3000
+auditservice:
+  type: process
+  path: ../auditservice
+  run: 'node index.js'
+  ports:
+    - main=8081
+mongo:
+  image: mongo
+  type: container
+  ports:
+    - main=27017:27017

Chapter10/service-discovery-with-dns/micro/webapp/app.js

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+var express = require('express')
+var path = require('path')
+var favicon = require('serve-favicon')
+var logger = require('morgan')
+var cookieParser = require('cookie-parser')
+var bodyParser = require('body-parser')
+
+var index = require('./routes/index')
+var users = require('./routes/users')
+var add = require('./routes/add')
+var audit = require('./routes/audit')
+
+var app = express()
+
+// view engine setup
+app.set('views', path.join(__dirname, 'views'))
+app.set('view engine', 'ejs')
+
+// uncomment after placing your favicon in /public
+// app.use(favicon(path.join(__dirname, 'public', 'favicon.ico')));
+app.use(logger('dev'))
+app.use(bodyParser.json())
+app.use(bodyParser.urlencoded({ extended: false }))
+app.use(cookieParser())
+app.use(express.static(path.join(__dirname, 'public')))
+
+app.use('/', index)
+app.use('/users', users)
+app.use('/add', add)
+app.use('/audit', audit)
+
+// catch 404 and forward to error handler
+app.use(function (req, res, next) {
+  var err = new Error('Not Found')
+  err.status = 404
+  next(err)
+})
+
+// error handler
+app.use(function (err, req, res, next) {
+  // set locals, only providing error in development
+  res.locals.message = err.message
+  res.locals.error = req.app.get('env') === 'development' ? err : {}
+
+  // render the error page
+  res.status(err.status || 500)
+  res.render('error')
+})
+
+module.exports = app

Chapter10/service-discovery-with-dns/micro/webapp/bin/www

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+#!/usr/bin/env node
+
+/**
+ * Module dependencies.
+ */
+
+var app = require('../app');
+var debug = require('debug')('webapp:server');
+var http = require('http');
+
+/**
+ * Get port from environment and store in Express.
+ */
+
+var port = normalizePort(process.env.PORT || '3000');
+app.set('port', port);
+
+/**
+ * Create HTTP server.
+ */
+
+var server = http.createServer(app);
+
+/**
+ * Listen on provided port, on all network interfaces.
+ */
+
+server.listen(port);
+server.on('error', onError);
+server.on('listening', onListening);
+
+/**
+ * Normalize a port into a number, string, or false.
+ */
+
+function normalizePort(val) {
+  var port = parseInt(val, 10);
+
+  if (isNaN(port)) {
+    // named pipe
+    return val;
+  }
+
+  if (port >= 0) {
+    // port number
+    return port;
+  }
+
+  return false;
+}
+
+/**
+ * Event listener for HTTP server "error" event.
+ */
+
+function onError(error) {
+  if (error.syscall !== 'listen') {
+    throw error;
+  }
+
+  var bind = typeof port === 'string'
+    ? 'Pipe ' + port
+    : 'Port ' + port;
+
+  // handle specific listen errors with friendly messages
+  switch (error.code) {
+    case 'EACCES':
+      console.error(bind + ' requires elevated privileges');
+      process.exit(1);
+      break;
+    case 'EADDRINUSE':
+      console.error(bind + ' is already in use');
+      process.exit(1);
+      break;
+    default:
+      throw error;
+  }
+}
+
+/**
+ * Event listener for HTTP server "listening" event.
+ */
+
+function onListening() {
+  var addr = server.address();
+  var bind = typeof addr === 'string'
+    ? 'pipe ' + addr
+    : 'port ' + addr.port;
+  debug('Listening on ' + bind);
+}

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

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+{
+  "name": "webapp",
+  "version": "0.0.0",
+  "private": true,
+  "scripts": {
+    "start": "node ./bin/www"
+  },
+  "dependencies": {
+    "body-parser": "~1.16.0",
+    "concordant": "^0.2.1",
+    "cookie-parser": "~1.4.3",
+    "debug": "~2.6.0",
+    "ejs": "~2.5.5",
+    "express": "~4.14.1",
+    "morgan": "~1.7.0",
+    "mu": "^2.1.2",
+    "restify": "^4.3.0",
+    "serve-favicon": "~2.3.2"
+  }
+}

Chapter10/service-discovery-with-dns/micro/webapp/public/stylesheets/style.css

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+body {
+  padding: 50px;
+  font: 14px "Lucida Grande", Helvetica, Arial, sans-serif;
+}
+
+a {
+  color: #00B7FF;
+}

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

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

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+'use strict'
+
+const { Router } = require('express')
+const restify = require('restify')
+const { dns } = require('concordant')()
+const router = Router()
+var client 
+
+router.get('/', resolve, respond)
+
+function resolve (req, res, next) {
+  if (client) {
+    next()
+    return
+  }
+  const auditservice = `_main._tcp.auditservice.micro.svc.cluster.local`
+  dns.resolve(auditservice, (err, locs) => {
+    if (err) {
+      next(err)
+      return
+    }
+    const { host, port } = locs[0]
+    client = restify.createJSONClient(`http://${host}:${port}`)
+  })
+}
+
+function respond (req, res, next) {
+  client.get('/list', (err, svcReq, svcRes, data) => {
+    if (err) { 
+      next(err)
+      return 
+    }
+    res.render('audit', data)
+  })
+}
+
+module.exports = router

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

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+var express = require('express')
+var router = express.Router()
+
+/* GET home page. */
+router.get('/', function (req, res, next) {
+  res.render('index', { title: 'Express' })
+})
+
+module.exports = router

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

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+var express = require('express')
+var router = express.Router()
+
+/* GET users listing. */
+router.get('/', function (req, res, next) {
+  res.send('respond with a resource')
+})
+
+module.exports = router

Chapter10/service-discovery-with-dns/micro/webapp/views/add.ejs

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+<!DOCTYPE html>
+<html>
+  <head>
+    <title>Add</title>
+    <link rel='stylesheet' href='/stylesheets/style.css' />
+  </head>
+  <body>
+    <h1>Add it up!</h1>
+    <form id='calc-form' action='/add/calculate' method='post'>
+      <input type='text' id='first', name='first' value=<%= first %>></input>
+      <input type='text' id='second', name='second' value=<%= second %>></input>
+    </form>
+    <button type="submit" form="calc-form" value="Submit">Submit</button>
+    <h2>result = <%= result %></h2>
+  </body>
+</html>

Chapter10/service-discovery-with-dns/micro/webapp/views/audit.ejs

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+<!DOCTYPE html>
+<html>
+  <head>
+    <title>Audit</title>
+    <link rel='stylesheet' href='/stylesheets/style.css' />
+  </head>
+  <body>
+    <h1>Calculation History</h1>
+    <ul>
+      <% list.forEach(function (el) { %>
+      <li>at: <%= new Date(el.ts).toLocaleString() %>, calculated: <%= el.calc %>, result: <%= el.result %></li>
+      <% }) %>
+    </ul>
+  </body>
+</html>

Chapter10/service-discovery-with-dns/micro/webapp/views/error.ejs

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+<h1><%= message %></h1>
+<h2><%= error.status %></h2>
+<pre><%= error.stack %></pre>

Chapter10/service-discovery-with-dns/micro/webapp/views/index.ejs

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+<!DOCTYPE html>
+<html>
+  <head>
+    <title><%= title %></title>
+    <link rel='stylesheet' href='/stylesheets/style.css' />
+  </head>
+  <body>
+    <h1><%= title %></h1>
+    <p>Welcome to <%= title %></p>
+  </body>
+</html>