MQTT with Java - a protocol for IoT and M2M communication

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Our digital world is growing rapidly and we have more devices connected to the internet than ever. On top of that each second 80 new devices are added, which introduces new challenges to communication between these devices. MQTT is a lightweight and scalable protocol that shifts the request/response paradigm of the web as it is today to an event-driven publish and subscribe architecture, which is a perfect fit for Internet of Things and M2M use cases. This talk answers the following three questions: Why do we need a paradigm shift, HTTP has been proven to be a good fit for the web? What is MQTT and how does it help to overcome the challenges we have today? How can everybody build their own MQTT application with the implementation that are available for Java developers ? In the last part we will dive into Eclipse Paho and the FuseSource client library and round up the talk with an live demonstration.

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MQTT with Java - a protocol for IoT and M2M communication

  1. 1. MQTT with Java - a protocol for IoT and M2M communication ! Christian Götz, dc-square
  2. 2. IoT?
  3. 3. M2M IoT IoE WoT Web of Things Internet of Things Internet of Everything Machine to Machine communication Ubicomp Ubiquitous computing CPS Cyper Physical Systems Pervasive Computing
  4. 4. Technology that connects Devices over wired or wireless communication
  5. 5. GPSGPS GPS GPS GPS GPS GPS Detected: Traffic Jam!
  6. 6. Hi, I’m Christian Götz author & speaker building solutions CEO & co-founder developer @goetzchr
  7. 7. IoT is happening now WHY?
  8. 8. 6,5 per person DEVICES outnumber people 0,0 15,0 30,0 45,0 60,0 2003 2010 2015 2020 50,0 25,0 12,5 0,5 6,0 19,5 33,0 46,5 60,0 2003 2010 2015 2020 7,67,36,86,3 250 new every sec http://blogs.cisco.com/news/cisco-connections-counter/ http://www.cisco.com/web/about/ac79/docs/innov/IoT_IBSG_0411FINAL.pdf 2020 in billions people devices
  9. 9. Open Hardware is everywhere Raspberry Pi is a trademark of the Raspberry Pi Foundation
  10. 10. Screenshot from JavaOne 2013 Java back to the roots
  11. 11. Screenshot from JavaOne 2013 Java back to the roots
  12. 12. HTTP is not suitable WHY?
  13. 13. Request/Response Point-2-Point widely known HTTP is too verbose
  14. 14. Challenges
  15. 15. Constrained devices Bi-directional Scalability Unreliable Networks Push Messaging Security … there are more ;) IoT HTTP IoT challenges
  16. 16. MQTT is a good fit WHY?
  17. 17. Subscribe
  18. 18. Publish
  19. 19. Temperaturfühler MQTT-Broker Laptop Mobiles Endgerät publish: “21°C“ publish: “21°C“ publish: “21°C“ subscribe subscribe
  20. 20. munich schwabing isarvorstadt people temp people temp / / MQTT topics 101
  21. 21. munich schwabing isarvorstadt people temp people temp / / munich/schwabing/temp MQTT topics 101
  22. 22. munich schwabing isarvorstadt people temp people temp / / munich/+/temp MQTT topics 101
  23. 23. munich schwabing isarvorstadt people temp people temp / / munich/schwabing/# MQTT topics 101
  24. 24. munich schwabing isarvorstadt people temp people temp / / # MQTT topics 101
  25. 25. On top of TCP Simple Publish/Subscribe Architecture BinaryMinimal Overhead Designed for unreliable networks Data agnostic MQTT facts
  26. 26. - Establishing 1st Connection
 (compensated after 5,5 min) + Reconnect + Maintaining Connection + Receiving Messages + Sending Messages less battery better throughput MQTT (with SSL) vs HTTPS + Less Overhead + Persistent Sessions + Pub/Sub Architecture Source: http://stephendnicholas.com/archives/1217
  27. 27. 1999 2010 2013 2014 Arlen Nipper & Andy Stanford-Clark invent MQTT royalty free OASIS TC formed MQTT becomes Standard MQTT history
  28. 28. Push instead of Poll Minimal Bandwidth is important Mobile meets Enterprise Unreliable networks Constrained devices Low Latency MQTT use cases
  29. 29. MQTT real world usage https://www.facebook.com/notes/facebook- engineering/building-facebook-messenger/ 10150259350998920
  30. 30. Quality of Service Retained Messages Last Will and Testament Persistent Sessions Heartbeats Topic Wildcards MQTT features
  31. 31. MQTT features Quality of Services QoS 1 QoS 2 QoS 0 B B B
  32. 32. MQTT features Last Will and Testament B Connect LWT device123/status: „offline“ B dropped device123/status: „offline“
  33. 33. MQTT features w/o Retained Messages B device1/temp: „23,0“ device1 every 5 min device2 device1/temp: „23,0“ Delay <= 5min
  34. 34. MQTT features Retained Messages B device1/temp: „23,0“ R device1 every 5 min device2 device1/temp: „23,0“ R No Delay!
  35. 35. MQTT features Persistent Sessions B Connect Subscribe device/+/status device/12/status: „1“ 1st B Re-Connect device/12/status: „1“ 2nd
  36. 36. MQTT-SN Overview Gateway MQTT-Broker MQTT-SN MQTT / -SN • UDP instead of TCP • Topic is just an ID (Preregister/Register) • Sleeping Clients • Different types of Gateways • Discovery Mechanisms Devices B
  37. 37. MQTT over Websockets
  38. 38. MQTT Security Protocol Username/Password Transport TLS, client certificate authentification Broker fine-grained authentication, 3rd party integration
  39. 39. Broker implementations What ?
  40. 40. MQTT Broker Mosquitto Open Source Ideal for constraint devices Supports Bridging Written in C
  41. 41. MQTT Broker HiveMQ High performance broker Open Plugin System for Java Clustering Bridging Scalable to > 100.000 connections Native Websocket support
  42. 42. MQTT Broker + others http://mqtt.org/wiki/doku.php/brokers
  43. 43. MQTT Broker Public Broker www.mqttdashboard.com
  44. 44. Getting Started How ?
  45. 45. MQTT Implementation
  46. 46. Open Source “Reference Implementation” Many languages: Java, Javascript, Lua, C, C++, Go, Python Active Community JS Library uses MQTT over Websockets Paho facts
  47. 47. MqttClient client = new MqttClient( "tcp://localhost:1883", //URI "publisher", //Client ID new MemoryPersistence()); //Persistence Paho Init Connection
  48. 48. MqttClient client = new MqttClient(...); ! MqttConnectOptions connOptions = new MqttConnectOptions(); ! connOptions.setKeepAliveInterval(120); connOptions.setWill("my/status", "offline".getBytes(), 2, true); connOptions.setCleanSession(false); connOptions.setUserName("user"); connOptions.setPassword(„pass".toCharArray( )); ! client.connect(connOptions); Paho Init Connection
  49. 49. ! ! client.publish("my/topic/123",//topic "Hello!".getBytes(), //message 1, //QoS false); //retained ! ! client.disconnect(); Paho Synchronous API
  50. 50. final MqttClient client = new MqttClient(...); client.setCallback(new MqttCallback() { @Override public void connectionLost(Throwable cause) {} ! @Override public void messageArrived(String topic, MqttMessage message)throws Exception { System.out.println(new String(message.getPayload())); } ! @Override public void deliveryComplete(IMqttDeliveryToken token) {} }); ! client.connect(); client.subscribe("#"); Paho Synchronous API
  51. 51. MqttAsyncClient client = new MqttAsyncClient(...); client.connect(null, new IMqttActionListener() { @Override public void onSuccess(IMqttToken asyncActionToken) { try { client.publish(...); } catch (MqttException e) {} } @Override public void onFailure(IMqttToken asyncActionToken, Throwable exception) {} }); ! client.disconnect(); Paho Asynchronous API
  52. 52. MQTT Implementation FuseSource MQTT Client
  53. 53. Open Source 3 API Styles Automatic Reconnect Maven Central Less active Community FuseSource facts
  54. 54. MQTT mqtt = new MQTT(); mqtt.setHost("localhost", 1883); mqtt.setClientId("publisher"); mqtt.setCleanSession(true); mqtt.setWillTopic("publisher/status"); mqtt.setWillMessage("offline"); mqtt.setKeepAlive((short) 60); mqtt.setUserName("mqtt-client"); mqtt.setPassword("mqtt"); FuseSource Init Connection
  55. 55. BlockingConnection connection = mqtt.blockingConnection(); ! connection.connect(); ! connection.publish( "publisher/status", // topic "online".getBytes(StandardCharsets.UTF_8), QoS.AT_MOST_ONCE, false); FuseSource Blocking API
  56. 56. FutureConnection connection = mqtt.futureConnection(); ! Future<Void> f1 = connection.connect(); f1.await(); ! Future<Void> f2 = connection.publish( "publisher/status", "online".getBytes(), QoS.AT_LEAST_ONCE, true); ! f2.await(); ! Future<Void> f3 = connection.disconnect(); f3.await(); FuseSource Future API
  57. 57. CallbackConnection connection = mqtt.callbackConnection(); connection.connect(new Callback<Void>() { public void onSuccess(Void v) { connection.publish( "publisher/status", "online".getBytes(), QoS.AT_LEAST_ONCE, false, new Callback<Void>() { public void onSuccess(Void v) {} public void onFailure(Throwable value){} }); } ! public void onFailure(Throwable value) {} }); FuseSource Callback API
  58. 58. It’s Showtime Demo
  59. 59. Demo from device to the web with MQTT https://github.com/dc-square/mqtt-with-paho-eclipsecon2013 available on
  60. 60. Demo Under the hood
  61. 61. Danke! Thanks! @goetzchr

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