IoT Weather

This application acts as a gateway that gets the weather data from MySQL DB and send it into IoT Central through devices (one per weather station).

Architecture

Development Environment Setup

1. Install .NET 6
2. Install VS Code
3. Install C# VS Code extension
4. Create My SQL Database (preferably in Azure), get the connection string.
5. Install a MySQL database client such as DBeaver or MySQL Workbench
6. Create the database using the setup/database.sql script.
7. Create an IoT Central application. Import Weather Station device template into the application.
8. Setup a new ADX Cluster with a database. Use the setup/WeatherStation.kql file to create a table.
9. Setup Continuous Data Export (CDE) to the above database and table. Use the setup/transform.jq to transform and insert telemetry data into the table.

Build and run Application

1. To build the application, run dotnet build from the root folder.
2. Copy setup/DigiCertGlobalRootCA.crt.pem file to bin/debug/net6.0 folder. This is needed to connect to MySQL Database running in Azure.
3. Export Environment environment variable to type of environment you are running the app (development. test, prod). E.g. SET Environment=development on windows or export Environment=development on Linux. You can override default settings in appsettings.json in the appsettings.{Envuronment}.json file.
4. In bin/debug/net6.0 folder, add appsettings.development.json file with the override parameters. Do not check this file into source as it contains secrets. This should be preferably stored in a Keyvault. You can adjust rest of the default parameters such as RefreshInterval by overriding them in this file. E.g.

{
    "Settings": {
        "Database": {
            "ConnectionString": "Server=YOUR_DB_SERVER.mysql.database.azure.com;UserID=YOUR_USER_NAME;Password=YOUR_PASSWORD;Database=weather;SslMode=Required;SslCa=DigiCertGlobalRootCA.crt.pem"
        },
        "IoTCentral": {
            "IDScope": "YOUR APP IDSCOPE",
            "GroupSASKey": "YOUR APP GROUP SAS KEY"
        }
    }
}

5. To run the application, run the weatherdb.exe from bin/debug/net6.0 folder.
6. Log files will be generated in logs folder. Log file will be rotated once a day.

Settings format

This application is configurable through appsettings.json file. The following is the format of the file.

{
    "Settings": {
        "Database": {
            "ConnectionString": ""
        },
        "IoTCentral": {
            "GlobalDeviceEndpoint ": "global.azure-devices-provisioning.net",
            "IDScope": "",
            "GroupSASKey": "",
            "ModelId": "dtmi:demobc:WeatherStation;1"
        },
        "DataGenerator": {
            "Enabled": true,
            "GenerationInterval": 60,
            "StationCount": 300
        },
        "Gateway": {
            "Enabled": true,
            "ConcurrentConnectionLimit": 50,
            "ConcurrentMessageLimit": 50,
            "RefreshInterval": 60
        }
    }
}

Parameter	Description
Database
ConnectionString	MySQL Database connection string. You can get it from the Development environment setup step #4
IoTCentral
GlobalDeviceEndpoint	DPS Registration global endpoint. For public cloud it is global.azure-devices-provisioning.net
IDScope	IoT Central application DPS IDScope. You can get it from IoT Central -> Administration -> Device connection -> ID Scope
GroupSASKey	IoT Central application group SAS key. You can get it from IoT Central -> Administration -> Device connection -> Enrollment groups -> SAS-IoT-Devices -> Primary Key
ModelID	The identity of the device template. If you used the Weatherstation, it is dtmi:demobc:WeatherStation;1
DataGenerator
Enabled	If this is set to true, data will be generated and inserted into database. If this is set to false, no data is inserted
GenerationInterval	How often (in seconds) should the data generator generate data?
StationCount	Number of weather stations to generate data for
Gateway
Enabled	If this is set to true, gateway will read data from database and send it to IoT Central. If this is set to false, no data is setnt to IoT Central
ConcurrentConnectionLimit	Number of concurrent connections to be opened to IoT Central
ConcurrentMessageLimit	Number of concurrent telemetry messages to be sent to IoT Central
RefreshInterval	How often (in seconds) should the gateway scan for telemetry in the database to be sent data to IoT Central?