Create a Cloud Connector

Cloud connectors are a feature of the Zentri Device Management Service (DMS) that provides a secure authenticated connection between a device and a 3rd party cloud service such as Amazon Web Services, Microsoft Azure, and more. In this section of the tutorial, you will learn how to create a cloud connector and use it to send data to a cloud application called Graffiti located at https://graffiti.zentri.com . Graffiti enables a way to quickly evaluate and demonstrate DMS cloud connectors. It is not a production cloud application and cannot be used for real-world IoT application.

Note! Before continuing complete the basic tutorial found here: Native C Application Development Tutorial . This section will build upon the steps found in that tutorial.

The source code for the completed could connector tutorial can be found here: main.c .

As discussed in Setting up your device for development , a development product for your device is automatically created on the DMS when you set up the device. To set up a cloud connector, first log into DMS and view your development products.

Click on the <User Code>-WEATHER project then select Connectors .

Select the Create Connector button then create a connector as shown below.

Field	Description
Title	Enter a title for your connector
Code	A code used to identify the Connector for the product. The code must be unique for YOUR Product and becomes part of the cloud URL where the sensor data is accessed online. The example below uses the customer code to make the unique code `03MWMCWEATHER` but this code can be anything as long as it is unique.
Type	Webhook
Endpoint	REST
URL	https://graffiti.zentri.com/connector/<code > where <code> matches the code entered above; when used with a Graffiti URL, the otherwise case-sensitive code is automatically converted to lower case
Authentication	None

Select Save

Next, modify the function read_and_report_event_handler() to post data to the cloud as shown below. The changes are highlighted in blue. Note! The cloud connector code created in the previous step is used again in the code below. Change the highlighted source to exactly match the <code> for the DMS connector created in the previous section. Note that the <code> is case-sensitive.


static void read_and_report_event_handler(void arg)
{ gos_result_t result = GOS_SUCCESS;
    uint32_t rh_data;
    int32_t temp_data;
    char temp_float_str[10];
    char rh_float_str[10];
    gos_msgpack_context_t weather_msgpack = NULL;
    const gos_dms_messsage_config_t config =
    {
      .length                 = 0,
      .is_response            = false,
      .response.handler       = 0,
      .response.timeout_ms    = 90000     //90 second timeout
    };

    //Read the measurement results
    Si7013_ReadNoHoldRHAndTemp(&si7021_device, 0, &rh_data, &temp_data);

    //Format the results to a floating point number and output to the console
    GOS_LOG("Temp: %s C | RH: %s %%",
             float_to_str((float)(temp_data/1000.0), temp_float_str, 1),
             float_to_str((float)(rh_data/1000.0), rh_float_str, 1));

    // Initialize the write context
    if(GOS_FAILED(result, gos_dms_message_write_init(&weather_msgpack, &config)))
    {
      return;
    }

    gos_msgpack_write_dict_marker(weather_msgpack, 3);
    gos_msgpack_write_dict_str(weather_msgpack, "request", "webhook");      // the connector is of type webhook
    gos_msgpack_write_dict_str(weather_msgpack, "code", "03MWMCWEATHER");   // code must match connector setup on DMS
    gos_msgpack_write_dict_dict(weather_msgpack, "data", 2);                // container for the data

    // Add ambient light data to the msgpack
    gos_msgpack_write_dict_dict(weather_msgpack, "Temperature", 5);
    gos_msgpack_write_dict_str(weather_msgpack, "value", temp_float_str);
    gos_msgpack_write_dict_str(weather_msgpack, "min", "0");
    gos_msgpack_write_dict_str(weather_msgpack, "max", "50");
    gos_msgpack_write_dict_str(weather_msgpack, "units", "");
    gos_msgpack_write_dict_str(weather_msgpack, "precision", "1");

    // Add prox data to the msgpack
    gos_msgpack_write_dict_dict(weather_msgpack, "Humidity", 5);
    gos_msgpack_write_dict_str(weather_msgpack, "value", rh_float_str);
    gos_msgpack_write_dict_str(weather_msgpack, "min", "0");
    gos_msgpack_write_dict_str(weather_msgpack, "max", "1000");
    gos_msgpack_write_dict_str(weather_msgpack, "units", "");
    gos_msgpack_write_dict_str(weather_msgpack, "precision", "1");

    // Send the message to the DMS
    if(GOS_FAILED(result, gos_dms_message_write_flush(weather_msgpack)))
    {
      gos_dms_message_context_destroy(weather_msgpack);
    }

    GOS_LOG("Posting sensor data to the cloud via a DMS Cloud Connector");

}

Build and download the application to the device.

View the Sensor Data in the Cloud Service

Using a browser, go to https://graffiti.zentri.com/<code > where <code> is the same code used for the cloud connector (the code should be lower case in the URL!). Weather data from your board should appear similar to the screen capture below.