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Custom Integration

Introduction

Custom integration is only executed remotely from the main IoT Hub instance. It allows to create integration with custom configuration that will use any transport protocol for communication with your devices.

This guide contains step-by-step instructions on how to create and launch IoT Hub custom integration. For example, we will launch custom integration that uses TCP transport protocol to stream data from devices and pushes the converted data to iothub.magenta.at.

Before we start, you can find the full code of custom integration example that we will use in this guide here.

Prerequisites

We assume you already have a tenant administrator account on your own IoT Hub v2.4.1+ instance or iothub.magenta.at.

Let’s assume that we have a sensor which is sending current temperature, humidity and battery level readings respectively in the following format: “25,40,94”.

Before setting up a custom integration, you need to create an Uplink and a Downlink converters.

Let’s create uplink converter.

image

NOTE: Although the Debug mode is very useful for development and troubleshooting, leaving it enabled in production mode may tremendously increase the disk space, used by the database, because all the debugging data is stored there. It is highly recommended to turn the Debug mode off when done debugging.

See the following script that is pasted to the Decoder function section:

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/** Decoder **/

// decode payload to string
var decodedString = decodeToString(payload);
// remove unnecessary [\"] and split by [,] to get an array
var payloadArray = decodedString.replace(/\"/g, "").split(',');
var result = {
    deviceName: "Device A",
    deviceType: "type",
    telemetry: {
        // get each reading from the array and convert the string value to a number
        temperature: Number(payloadArray[0]),
        humidity: Number(payloadArray[1]),
        batteryLevel: Number(payloadArray[2])
    },
    attributes: {}
};

/** Helper functions **/

function decodeToString(payload) {
    return String.fromCharCode.apply(String, payload);
}

function decodeToJson(payload) {
   // convert payload to string.
   var str = decodeToString(payload);

   // parse string to JSON
   var data = JSON.parse(str);
   return data;
}

return result;

The purpose of the decoder function is to parse the incoming data and metadata to a format that IoT Hub can consume. deviceName and deviceType are required, while attributes and telemetry are optional. Attributes and telemetry are flat key-value objects. Nested objects are not supported.

We will not use the Downlink converter in this guide so there is no need to create one. In case you have another use case, please refer to the following instructions.

Custom Integration Setup

Let’s create custom integration.

image

Notice that Execute remotely is enabled automatically when we choose Custom type and we enable Debug mode.

Integration class is used to create an instance of the integration using the Java reflective method.

The Integration JSON configuration is the custom configuration that has two fields in our case:

  • port, which will be used to bind the TCP server-client communication
  • msgGenerationIntervalMs, the interval between generating the messages

We will get back to this later in this guide.

Custom Integration Application

Download the sample application

Feel free to grab the code from the IoT Hub repository and build the project with maven:

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mvn clean install

Go ahead and add that maven project to your favorite IDE.

Dependencies review

Main dependencies that are used in the project:

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<!-- Api IoT Hub provides to create custom integration -->
<dependency>
    <groupId>org.thingsboard.common.integration</groupId>
    <artifactId>remote-integration-api</artifactId>
    <version>${thingsboard.version}</version>
</dependency>
<!-- Netty for TCP client-server implementation -->
<dependency>
    <groupId>io.netty</groupId>
    <artifactId>netty-all</artifactId>
    <version>${netty.version}</version>
</dependency>
<!-- Grpc transport between remote integration and IoT Hub -->
<dependency>
    <groupId>io.grpc</groupId>
    <artifactId>grpc-netty</artifactId>
    <version>${grpc.version}</version>
</dependency>

Source code review

Main source code is the CustomIntegration Java class. Integration is expecting “Hello to IoT Hub” message from the TCP client and replies with the “Hello from IoT Hub!”. Once the client emulator receives “Hello from IoT Hub!” , it will start sending auto-generated data to IoT Hub in the following format: “25,40,94”. The Integration will pass the incoming message as-is to the uplink converter and push data to IoT Hub.

Next steps

  • Getting started guides - These guides provide quick overview of main IoT Hub features. Designed to be completed in 15-30 minutes.