Dominik Obermaier | dc-square GmbH

M2M for Java Developers with MQTT

About meHi, I’m Dominik Obermaier.• CTO of dc-square

• HiveMQ architect

• helped standardizing MQTT at OASIS

• Speaker and author about MQTT, M2M and IoT

@dobermai

• Typical morning

https://flic.kr/p/eaX1GC

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https://flic.kr/p/48VxKfhttps://flic.kr/p/hLd8CU

• Macbook E-Mail Stockphoto

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• Dusche Stockphoto

https://flic.kr/p/6JuGDb

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• Imagine Bild

• Internet of Things

Internet of Things

The Internet of Things (IoT) refers to uniquely identifiable objects and their virtual representations in an

Internet-like structure

Why should

we care?

Some statistics

2010 2015 2020

~6.909.000.000 ~7.302.000.000 ~7.675.000.000

~12.500.000.000 ~25.000.000.000 ~50.000.000.000

[1]Source: http://www.un.org/esa/population/publications/wpp2008/wpp2008_highlights.pdf

[1]

[2]Source: http://share.cisco.com/internet-of-things.html

[2]

Some statistics

0

12,500,000,000

25,000,000,000

37,500,000,000

50,000,000,000

2010 2015 2020

People Things

Some statistics

0

12,500,000,000

25,000,000,000

37,500,000,000

50,000,000,000

2010 2015 2020

People Things

1.8x

Some statistics

0

12,500,000,000

25,000,000,000

37,500,000,000

50,000,000,000

2010 2015 2020

People Things

1.8x

3.4x

Some statistics

0

12,500,000,000

25,000,000,000

37,500,000,000

50,000,000,000

2010 2015 2020

People Things

1.8x

3.4x

6.5x

https://flic.kr/p/athSFb

• Android Photo

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Evolution?

Revolution?

M2M?https://flic.kr/p/834e93

TECHNOLOGY THAT SUPPORTS WIRED

OR WIRELESS COMMUNICATION BETWEEN DEVICES

M2MInternet of Things

RFID

Bluetooth

Barcode

Non-IP

Why now?

https://flic.kr/p/8EidjG

https://flic.kr/p/daTVZY

Screenshot Taken from Oracle JavaOne Strategic Keynote 2013

Are we there yet?

https://flic.kr/p/5WR2fd

ChallengesSecurity Identity

ManagementInteroperability

PrivacyProvisioning

ScalabilityBIG Data

Device Management

...

Protocols?

Application Protocols

CoAP

HTTP

‣ efficient in bandwidth

‣ scalable

‣ standardized

‣ open

‣ data agnostic

‣ must be suited for constrained devices AND server infrastructure

Requirements for an IoT Protocol

Request / Response

Verbose

Polling instead of Push

No quality of service

How to get notified if clients die?

Stateless

HTTP?

What is MQTT‣ Messaging Protocol

‣ Simple

‣ On top of TCP

‣ Publish / Subscribe Architecture

‣ Binary protocol

‣ Minimal Overhead

‣ Designed for unreliable networks

‣ Data agnostic

Use cases‣ Push instead of Poll

‣ Bandwidth is at a premium

‣ Enterprise applications should interact with mobile applications

‣ Reliable delivery of messages over unreliable networks

‣ Constrained devices

‣ Low latency

Features‣ Topic Wildcards

‣ 3 Quality of Service Levels

‣ Retained Messages

‣ Last Will and Testament

‣ Persistent Sessions

‣ Heartbeats

Publish / Subscribe

Publish / Subscribe

MQTT Topics

‣ Hierarchical

‣ Very lightweight

‣ Subtopic-Level Wildcards (+)

‣ Subtree-Level Wildcards (#)

‣ Max 64.000 characters

‣ Clients can publish / subscribe to N topics

‣ Brokers can queue for topics if QoS > 0

MQTT Topics

MQTT Topics

MQTT Topicshouse1/floor1/kitchen/light

MQTT Topicshouse1/floor1/kitchen/light

house1/floor1/kitchen/+

MQTT Topicshouse1/floor1/kitchen/light

house1/floor1/kitchen/+

house1/floor1/+/light

MQTT Topicshouse1/floor1/kitchen/light

house1/floor1/kitchen/+

house1/floor1/+/light

house1/+/+/light

MQTT Topicshouse1/floor1/kitchen/light

house1/floor1/kitchen/+

house1/floor1/+/light

house1/+/+/light

house1/#

MQTT Topicshouse1/floor1/kitchen/light

house1/floor1/kitchen/+

house1/floor1/+/light

house1/+/+/light

house1/#

+/floor1/+/#

MQTT Topicshouse1/floor1/kitchen/light

house1/floor1/kitchen/+

house1/floor1/+/light

house1/+/+/light

house1/#

+/floor1/+/#

+/+/+/#

MQTT Topics

MQTT/is/awesome MQTT/is/fantastic

Bacon/is/awesome

MQTT/looks/fantasticBacon/looks/fantastic

MQTT Topics

MQTT Bacon

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MQTT Topics

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MQTT Topics

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MQTT Topics

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MQTT Topics

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MQTT Topics

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MQTT Topics

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MQTT Topic Level Wildcard

MQTT Bacon

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+/is/awesome

MQTT Topic Level Wildcard

MQTT Bacon

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MQTT Topic Level Wildcard

MQTT Bacon

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looks

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MQTT Topic Level Wildcard

MQTT Bacon

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looks

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+/is/awesome

MQTT Topic Level Wildcard

MQTT Bacon

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looks

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MQTT Topic Level Wildcard

MQTT Bacon

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looks

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MQTT Topic Level Wildcard

MQTT Bacon

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MQTT Topic Level Wildcard

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MQTT Topic Level Wildcard

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MQTT Topic Level Wildcard

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MQTT Topic Level Wildcard

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MQTT Subtree Wildcard

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MQTT/#

MQTT Subtree Wildcard

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MQTT Subtree Wildcard

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#

MQTT Subtree Wildcard

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MQTT Subtree Wildcard

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MQTT Subtree Wildcard

MQTT Bacon

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MQTT Subtree Wildcard

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MQTT Subtree Wildcard

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MQTT Subtree Wildcard

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Quality of Service Levels

QoS 0 At most once delivery

The message is delivered once or never.

QoS 1 At least once delivery

The message is delivered once or more.

QoS 2 Exactly once delivery

The message is delivered exactly once.

Last Will and Testament‣ Clients can specify a LWT

‣ Broker publishes the LWT message on behalf of the client on “death”

‣ Useful for reporting problems

‣ Real push on device “death”

‣ Mostly used for reporting the connection status of a device

Retained messages‣ Last known good value

‣ Last message is stored for a topic

‣ Publishing clients decide if the message should be retained

‣ Clients automatically receive the retained message after subscribing

SecurityProtocol

‣ Username / Password

‣ Payload Encryption

Transport

‣ TLS

‣ Client certificate authentication

Broker

‣ Publish / Subscribe Permissions

‣ Integration to other systems (databases, APIs, ....)

History

1999 2010 2013 2014

MQTT inventedby IBM and

Arcom (Eurotech)

royalty free OASIS TC formed

MQTT is OASIS standard

Real world use cases

Use case:

‣ more than 850M Facebook Messenger Users

‣ Chat application

‣ Improved Battery

‣ Lower latency

‣ Less bandwidth

https://www.facebook.com/notes/facebook-engineering/building-facebook-messenger/10150259350998920

Facebook Messenger

Use case:

‣MQTT as central message “bus”

‣ Easy to integrate with other technologies

‣ Remote monitoring

‣ Many open source Smart Home Frameworks

support MQTT

‣ Remote control

Smart Home

Use case:

‣30.000 devices

‣ 17.000 km pipeline

‣ Remote monitoring

‣ Remote control

‣ Uses satellite links

‣ Bandwidth is very expensive

Pipelines

Gaining traction

Google Trends - 2014/05/13

MQTT Brokers

Mosquitto

‣ Open Source

‣ Ideal for running in constrained environments

‣ Supports Bridging

‣Written in C

HiveMQ‣ High Performance

MQTT broker

‣ Native Websockets Support

‣ Java Plugin System

‣ Clustering

‣ Bridging

‣ Scalable to > 100.000 connections

Other brokers

+ Many otherssee https://github.com/mqtt/mqtt.github.io/wiki/brokers

Scaling

HIER SCALING BILD

Bridging

Clustering

Broker comparisonQoS

0QoS

1QoS

2Auth Bridge $SYS SSL dynamic

topicscluster websockets plugins

HiveMQ ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔

mosquitto ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ X X ✔

RSMB ✔ ✔ ✔ ✔ ✔ ✔ X ✔ X X X

RabbitMQ ✔ ✔ X ✔ X X ✔ ✔ ? ? ?

ActiveMQ ✔ ✔ ✔ ? X X ? ? ? ✔ ?

MQTT Clients

Eclipse Paho‣ Open Source

‣ “Reference Implementation”

‣ Available in many languages: Java, Javascript, Lua, C, C++, Go, Python

‣ The JS library uses websockets

‣ Active Community

MqttClient client = new MqttClient( "tcp://localhost:1883", //URI "publisher", //Client ID new MemoryPersistence()); //Persistence

client.connect();

client.publish("the/topic", //topic "message".getBytes(), //message 1, //QoS false); //retained

client.disconnect();

MqttClient client = new MqttClient( "tcp://localhost:1883", //URI "publisher", //Client ID new MemoryPersistence()); //Persistence

MqttConnectOptions connOptions = new MqttConnectOptions();

connOptions.setKeepAliveInterval(120); connOptions.setWill("help/I/died",

new byte[0], 2, true); connOptions.setCleanSession(false); connOptions.setUserName("username"); connOptions.setPassword("passw".toCharArray());

client.connect(connOptions);

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();

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("#");

Fusesource MQTT Client

‣ Java

‣ 3 API Styles

‣ Very easy to intercept

‣ Based on HawtIO

‣ Very performant

‣ In Maven Central

MQTT mqtt = new MQTT(); mqtt.setHost("localhost", 1883); mqtt.setClientId("clientId"); mqtt.setCleanSession(false);

mqtt.setWillTopic("willtopic"); mqtt.setWillMessage("willmessage"); mqtt.setWillQos(QoS.EXACTLY_ONCE);

mqtt.setUserName("user"); mqtt.setPassword("passwd");

BlockingConnection conn = mqtt.blockingConnection();

conn.connect();

MQTT mqtt = new MQTT(); BlockingConnection conn =

mqtt.blockingConnection(); conn.connect();

conn.publish("the/topic", //topic "message".getBytes(), //message QoS.EXACTLY_ONCE, //QoS false);

conn.disconnect();

MQTT mqtt = new MQTT();

FutureConnection conn = mqtt.futureConnection(); Future<Void> connectFuture = conn.connect();

// funky business logic

connectFuture.await();

conn.publish("the/topic", //topic "message".getBytes(), //message QoS.EXACTLY_ONCE, //QoS false). then(new Callback<Void>() { @Override public void onSuccess(Void value) { System.out.println("Success"); }

@Override public void onFailure(Throwable value) {}});

MQTT mqtt = new MQTT(); CallbackConnection conn = mqtt.callbackConnection(); conn.connect(new Callback<Void>() { @Override public void onSuccess(Void value) { conn.publish("the/topic", //topic "message".getBytes(), //message QoS.EXACTLY_ONCE, //QoS false, //retain new Callback<Void>() { @Override public void onSuccess(Void value) { System.out.println("Published"); }

@Override public void onFailure(Throwable value) {} }); } @Override public void onFailure(Throwable value) {}});

Other MQTT Clients

https://github.com/mqtt/mqtt.github.io/wiki/libraries

MQTT over Websockets

‣ Every Browser is a ‘device’

‣ Device-to-Browser Push

‣ Broadcasting to all online users

‣ Detect if a user is offline

‣ Direct Browser-to-device push

‣ Minimum payload

‣ No application-specific protocol

MQTT over websockets

Thanks!@dobermai