设备数据通过Azure Functions 推送到 Power BI 数据大屏进行展示（1.准备工作）

本案例适用于开发者入门理解Azure Functions/ IoT Hub / Service Bus / Power BI等几款产品。

主要实战的内容为：

1. 将设备遥测数据上传到物联网中心，

2. 将遥测数据路由到消息中间件的Topic中，

3. 使用Azure Function解析消息中间件Topic中的消息并推送到大屏 。

本文主要是本案例的准备工作，即（第1条和第2条的内容）：

1.创建IoT Hub：

https://v.qq.com/x/page/h3031pnaxi8.html

2.创建Service Bus：

https://v.qq.com/x/page/b3031hdv9yk.html

3. 创建IoT Hub 消息路由，将遥测消息路由到Service Bus Topic

https://v.qq.com/x/page/i3031hkec4q.html

本示例中的Python Device 代码来自于微软官网，请参照：

https://docs.azure.cn/zh-cn/iot-hub/quickstart-send-telemetry-python

import random
import time
import sys

# Using the Python Device SDK for IoT Hub:
#   https://github.com/Azure/azure-iot-sdk-python
# The sample connects to a device-specific MQTT endpoint on your IoT Hub.
import iothub_client
# pylint: disable=E0611
from iothub_client import IoTHubClient, IoTHubClientError, IoTHubTransportProvider, IoTHubClientResult
from iothub_client import IoTHubMessage, IoTHubMessageDispositionResult, IoTHubError, DeviceMethodReturnValue

# The device connection string to authenticate the device with your IoT hub.
# Using the Azure CLI:
# az iot hub device-identity show-connection-string --hub-name {YourIoTHubName} --device-id MyNodeDevice --output table
CONNECTION_STRING = "your device conn string"

# Using the MQTT protocol.
PROTOCOL = IoTHubTransportProvider.MQTT
MESSAGE_TIMEOUT = 10000

# Define the JSON message to send to IoT Hub.
TEMPERATURE = 20.0
HUMIDITY = 60
MSG_TXT = "{"temperature": %.2f,"humidity": %.2f}"

def send_confirmation_callback(message, result, user_context):
    print ( "IoT Hub responded to message with status: %s" % (result) )

def iothub_client_init():
    # Create an IoT Hub client
    client = IoTHubClient(CONNECTION_STRING, PROTOCOL)
    return client

def iothub_client_telemetry_sample_run():

    try:
        client = iothub_client_init()
        print ( "IoT Hub device sending periodic messages, press Ctrl-C to exit" )

        while True:
            # Build the message with simulated telemetry values.
            temperature = TEMPERATURE + (random.random() * 15)
            humidity = HUMIDITY + (random.random() * 20)
            msg_txt_formatted = MSG_TXT % (temperature, humidity)
            message = IoTHubMessage(msg_txt_formatted)

            # Add a custom application property to the message.
            # An IoT hub can filter on these properties without access to the message body.
            prop_map = message.properties()
            if temperature > 30:
              prop_map.add("temperatureAlert", "true")
            else:
              prop_map.add("temperatureAlert", "false")

            # Send the message.
            print( "Sending message: %s" % message.get_string() )
            client.send_event_async(message, send_confirmation_callback, None)
            time.sleep(3)

    except IoTHubError as iothub_error:
        print ( "Unexpected error %s from IoTHub" % iothub_error )
        return
    except KeyboardInterrupt:
        print ( "IoTHubClient sample stopped" )

if __name__ == '__main__':
    print ( "IoT Hub Quickstart #1 - Simulated device" )
    print ( "Press Ctrl-C to exit" )
    iothub_client_telemetry_sample_run()