Customising device shadow

2min
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Every project in Bytebeam comes with a default Device Shadow﻿ stream. The stream by default contains just three fields Status, timestamp, and sequence. 
This guide shows how to create additional fields and write data to this stream from your application.

For that, Click on the username at the top right corner of the Bytebeam  cloud console and navigate to Settings 
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Here under the Stream Tab, you can find “device_shadow”
For example, add two new columns device_name and arch to the device shadow. You can do this by entering the field name and type and clicking the + button.
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After adding both fields your device shadow will look like the below:
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Now update your application to push this data to the device.
demo.py
demo.js
demo.rs
demo.go
package main

import (
	"encoding/json"
	"fmt"
	"net"
	"os"
	"strconv"
	"time"
)

// DeviceShadow represents the payload structure
type DeviceShadow struct {
	Stream      string `json:"stream"`
	Sequence    int    `json:"sequence"`
	Timestamp   int64  `json:"timestamp"`
	DeviceName  string `json:"device_name"`
	Arch        string `json:"arch"`
}

func sendData(conn net.Conn, payload interface{}) {
	data, _ := json.Marshal(payload)
	fmt.Println(string(data))
	conn.Write(append(data, '\n'))
}

// sendDeviceShadow constructs and sends a device shadow payload
func sendDeviceShadow(conn net.Conn, sequence int) {
	t := time.Now().UnixNano() / int64(time.Millisecond)
	payload := DeviceShadow{
			Stream:      "device_shadow",
			Sequence:    sequence,
			Timestamp:   t,
			DeviceName:  "Beaglebone Black Rev. C",
			Arch:        "armv7",
	}
	fmt.Println(payload)
	sendData(conn, payload)(conn, payload)
}

func main() {
	conn, err := net.Dial("tcp", "localhost:5050")
	if err != nil {
			fmt.Println("Error connecting:", err.Error())
			os.Exit(1)
	}
	defer conn.Close()

	fmt.Println("Starting Uplink Bridge App")

	sequence := 1
	for {
			time.Sleep(5 * time.Second)
			sendDeviceShadow(conn, sequence)
			sequence++
	}
}
package main

import (
	"encoding/json"
	"fmt"
	"net"
	"os"
	"strconv"
	"time"
)

// DeviceShadow represents the payload structure
type DeviceShadow struct {
	Stream      string `json:"stream"`
	Sequence    int    `json:"sequence"`
	Timestamp   int64  `json:"timestamp"`
	DeviceName  string `json:"device_name"`
	Arch        string `json:"arch"`
}

func sendData(conn net.Conn, payload interface{}) {
	data, _ := json.Marshal(payload)
	fmt.Println(string(data))
	conn.Write(append(data, '\n'))
}

// sendDeviceShadow constructs and sends a device shadow payload
func sendDeviceShadow(conn net.Conn, sequence int) {
	t := time.Now().UnixNano() / int64(time.Millisecond)
	payload := DeviceShadow{
			Stream:      "device_shadow",
			Sequence:    sequence,
			Timestamp:   t,
			DeviceName:  "Beaglebone Black Rev. C",
			Arch:        "armv7",
	}
	fmt.Println(payload)
	sendData(conn, payload)(conn, payload)
}

func main() {
	conn, err := net.Dial("tcp", "localhost:5050")
	if err != nil {
			fmt.Println("Error connecting:", err.Error())
			os.Exit(1)
	}
	defer conn.Close()

	fmt.Println("Starting Uplink Bridge App")

	sequence := 1
	for {
			time.Sleep(5 * time.Second)
			sendDeviceShadow(conn, sequence)
			sequence++
	}
}
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You should now be able to see the new fields on Bytebeam cloud:
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Updated 23 Nov 2023
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