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Use Carbon Aware SDK with an Azure Function

Overview​

The sample included showcase the Azure Functions tooling for the Carbon Aware SDK C# Class Library. It includes an implementation for GetAverageCarbonIntensity and for GetCurrentForecast. GetAverageCarbonIntensity uses the EmissionsHandler to return the carbon intensity rate of a location for a specific timespan. GetCurrentForecast uses the ForecastHandler to yield the optimal time of a specified location and duration.

The functions can run locally for debugging or be deployed to Azure. See the data source configuration docs for detailed information about configuring the data source(s) your Azure Function will use.

Azure Function Dependency Injection​

The Carbon Aware SDK is included in the function .csproj file by creating and adding the SDK as a package. The Program.cs file uses dependency injection to access the handlers in the library. The following code initializes the C# Library:

    // omitted
    .ConfigureServices((context,services) => {
        services.AddApplicationInsightsTelemetryWorkerService();
        services.ConfigureFunctionsApplicationInsights();
        services.AddEmissionsServices(context.Configuration);
        services.AddForecastServices(context.Configuration);
    })
    // omitted

Run Function Locally​

Both Azure Function apps can be run locally without needing an Azure subscription. The process for running both is the same, as they use the same configuration, just call different paths within the SDK.

Prerequisites to Run​

.NET Core SDK

Azure Functions Core Tools

Start Function​

To run and debug locally, update the appsettings.json file to include the desired configuration.

In the app folder (samples/azure/azure-function), run the command: func start

After the function has compiled and is running, the URLs to the functions will be presented.

Example call for Get Average Carbon Intensity function​

The following example will retrieve the Average Carbon Intensity. For this example, query parameters were used, but the values could also be sent in the body of the request.

curl --location --request GET 'http://localhost:7071/api/GetAverageCarbonIntensity?startDate=2022-03-01T15:30:00Z&endDate=2022-03-01T18:30:00Z&location=eastus'

Example call for Get Current Forecast function​

The following example will call the Current Forecast route. The request can use either the request body or query parameters.

curl --location --request GET 'http://localhost:7071/api/GetCurrentForecast' \
--header 'Content-Type: application/json' \
--data-raw '{
    "startDate": "2022-11-02T15:30:00Z",
    "endDate": "2022-11-02T18:30:00Z",
    "location" : "eastus",
    "duration": 15
}'

Note: startDate and endDate must be a valid interval within the future 24 hours from the time of calling.

Deploy to Azure​

If you have an Azure subscription, you can also deploy these functions to Azure.

Prerequisites to Deploy​

You must have the Azure CLI or Azure PowerShell installed locally to be able to publish to Azure.

Azure Functions Core Tools

Create Function App​

Log in to Azure: az login

Once the correct subscription is selected run the following script to create a new function app:

# Function app and storage account names must be unique.

# Variable block
let "randomIdentifier=$RANDOM*$RANDOM"
location="eastus"
resourceGroup="carbon-aware-$randomIdentifier"
storage="casaccount$randomIdentifier"
functionApp="carbon-aware-functionapp-$randomIdentifier"
skuStorage="Standard_LRS"
functionsVersion="3"

# Create a resource group
echo "Creating $resourceGroup in "$location"..."
az group create --name $resourceGroup --location "$location"

# Create an Azure storage account in the resource group.
echo "Creating $storage"
az storage account create --name $storage --location "$location" --resource-group $resourceGroup --sku $skuStorage

# Create a serverless function app in the resource group.
echo "Creating $functionApp"
az functionapp create --name $functionApp --storage-account $storage --consumption-plan-location "$location" --resource-group $resourceGroup --functions-version $functionsVersion

Publish Functions​

Update the appsettings.json file to include the desired configuration.

To publish the function code to a function app in Azure, use the publish command in the samples/azure/azure-function folder:

func azure functionapp publish $functionApp

References​

Azure Functions developer guide

Use dependency injection in .NET Azure Functions

Run functions locally

Create a function app for serverless code execution