Get started with MQTT

This tutorial will show you step-by-step how to test the connection of your devices to Servitly using the MQTT standard protocol.
To publish data through the MQTT protocol, you can download the Eclipse PAHO library, which is available in several programming languages. Check out the PAHO download page for more details.
You can download the source code (Java) of the sample project used in this tutorial here.

DPS Account creation

1. Create a new account on https://lab.servitly-sandbox.com/

2. When done, log in and select the "My Home" location.

3. Press the (+) button to create new Equipment
   
   

• Name: The mnemonic name of the equipment you are creating.

• Serial Number: The equipment’s unique serial number (e.g., SN-12345).

• Thing Definition: Select Generic-Device which is the default definition for testing that includes a predefined set of metrics, commands, configuration parameters, and event/alert definitions.

• GPS Position: The coordinates where the device is installed (Optional). By default, it’s inherited from the location if specified.

MQTT Connector Configuration

Once saved, go to the equipment Connection tab to configure how the Equipment will connect to the cloud. Provide the following information:

MQTT Client

package com.servitly.samples.mqtt;

import java.util.Random;

import org.eclipse.paho.client.mqttv3.MqttClient;
import org.eclipse.paho.client.mqttv3.MqttConnectOptions;
import org.eclipse.paho.client.mqttv3.MqttException;
import org.eclipse.paho.client.mqttv3.MqttMessage;

import com.fasterxml.jackson.databind.node.JsonNodeFactory;
import com.fasterxml.jackson.databind.node.ObjectNode;

/**
 * This sample class uses the PAHO client to publish a message to the MQTT broker.
 */
public class PublishSample {

 private static final String BROKER_URL = "ssl://mqtt.servitly-sandbox.com:8883";

 private static final String USERNAME = "<USERNAME>";
 private static final String PASSWORD = "<PASSWORD>";
 private static final String ASSET_ID = "<ASSET_ID>";

 private static final String METRIC_PATH = "measures";

 public static void main(String[] args) {
    try {

       // create the Servitly payload
       ObjectNode payload = JsonNodeFactory.instance.objectNode();
       payload.put("ts", System.currentTimeMillis());
       ObjectNode data = JsonNodeFactory.instance.objectNode();
       Random random = new Random();
       data.put("measure1", 42 + random.nextInt(10));
       data.put("measure2", 24 + random.nextInt(10));
       payload.set("data", data);

       // create the MQTT Client
       MqttClient mqttClient = new MqttClient(BROKER_URL, USERNAME + "_PUB");
       MqttConnectOptions connOpts = new MqttConnectOptions();
       connOpts.setCleanSession(true);
       connOpts.setUserName(USERNAME);
       connOpts.setPassword(PASSWORD.toCharArray());

       // open MQTT connection
       System.out.println("Connecting to MQTT broker: " + BROKER_URL);
       mqttClient.connect(connOpts);
       System.out.println("Connected");

       // publish message
       String topic = String.format("%s/%s/%s", USERNAME, ASSET_ID, METRIC_PATH);
       System.out.println("==> Publishing message to " + topic);
       System.out.println(payload.toPrettyString());
       MqttMessage message = new MqttMessage(payload.toString().getBytes());
       message.setQos(1);
       mqttClient.publish(topic, message);
       System.out.println("Message published");

       // disconnect client
       mqttClient.disconnect();
       mqttClient.close();
       System.out.println("Client disconnected");
    } catch (MqttException me) {
       System.out.println("Reason: " + me.getReasonCode());
       System.out.println("Message: " + me.getMessage());
       System.out.println("Cause: " + me.getCause());
       me.printStackTrace();
    }
 }
}

private static final String BROKER_URL = "ssl://mqtt.servitly-sandbox.com:8883";

// fields to replace
private static final String USERNAME = "<USERNAME>";
private static final String PASSWORD = "<PASSWORD>";
private static final String ASSET_ID = "<ASSET_ID>";

ObjectNode payload = JsonNodeFactory.instance.objectNode();
payload.put("ts", System.currentTimeMillis());
ObjectNode data = JsonNodeFactory.instance.objectNode();
Random random = new Random();
data.put("measure1", 42 + random.nextInt(10));
data.put("measure2", 24 + random.nextInt(10));
payload.set("data", data);

{
  "ts": 1605179226000,
  "data":{
    "measure1": 42,
    "measure2": 24
  }
}

Publish the MQTT message

// create the MQTT Client
MqttClient mqttClient = new MqttClient(BROKER_URL, USERNAME + "_PUB");
MqttConnectOptions connOpts = new MqttConnectOptions();
connOpts.setCleanSession(true);
connOpts.setUserName(USERNAME);
connOpts.setPassword(PASSWORD.toCharArray());

// open MQTT connection
System.out.println("Connecting to MQTT broker: " + BROKER_URL);
mqttClient.connect(connOpts);
System.out.println("Connected");

// publish message
String topic = String.format("%s/%s/%s", USERNAME, ASSET_ID, METRIC_PATH);
System.out.println("==> Publishing message to " + topic);
System.out.println(payload.toPrettyString());
MqttMessage message = new MqttMessage(payload.toString().getBytes());
message.setQos(1);
mqttClient.publish(topic, message);
System.out.println("Message published");

Parameter1 can be updated directly within the dashboard, using the corresponding configuration parameter in the Overview tab.
To receive data from Servitly for the Parameter 1 parameter, the MQTT client has to subscribe to the following topic:

<USERNAME>/<ASSET-ID>/command

mqttClient.subscribe(topic, new IMqttMessageListener() {

 @Override
 public void messageArrived(String topic, MqttMessage message) throws Exception {
    JsonNode payload = JSON_MAPPER.readTree(message.getPayload());
    System.out.println("<== Incoming message from " + topic);
    System.out.println(payload.toPrettyString());
 }

});

Technical restrictions