Carbon Aware Computing Hangfire Extension

Overview

A Hangfire extension to schedule tasks with carbon awareness in mind. The best point in time is calculated based on emission forecasts to get a window with a minimal grid carbon intensity.

Installation

CarbonAwareComputing.Hangfire is available as a NuGet package. You can install it using the NuGet Package Console window:

Install-Package CarbonAwareComputing.Hangfire

After installation add the extension to the Hangfire configuration.

builder.Services.AddHangfireCarbonAwareExecution(configuration => configuration .UseCarbonAwareExecution(new CarbonAwareDataProviderOpenData(), ComputingLocations.Germany) );

Usage

There are extension to Enqueue and Schedule with WithCarbonAwarenessAsync.

Fire and Forget tasks

Setup the latest execution time and the estimated task duration. The extension will do a best effort to get a window with the estimated task duration and minimal grid carbon intensity. When no window can be detected, the task is enqueued immediately.

//use the extension methods IBackgroundJobClient client = GetBackgroundJobClient(); await client.EnqueueWithCarbonAwarenessAsync( () => Console.WriteLine("Enqueue carbon aware jobs"), DateTimeOffset.Now + TimeSpan.FromHours(2), TimeSpan.FromMinutes(5)); //or use the static versions await CarbonAwareBackgroundJob.EnqueueAsync( () => Console.WriteLine("Enqueue carbon aware jobs"), DateTimeOffset.Now + TimeSpan.FromHours(2), TimeSpan.FromMinutes(5));

Delayed tasks

Setup the earliest and latest execution time and the estimated task duration. The extension will do a best effort to get a window with the estimated task duration and minimal grid carbon intensity. When no window can be detected, the task is scheduled as desired.

//use the extension methods IBackgroundJobClient client = GetBackgroundJobClient(); await client.ScheduleWithCarbonAwarenessAsync( () => Console.WriteLine("Schedule carbon aware jobs"), DateTimeOffset.Now + TimeSpan.FromHours(2), TimeSpan.FromMinutes(20), TimeSpan.FromMinutes(30), TimeSpan.FromMinutes(5)); //or use the static versions await CarbonAwareBackgroundJob.ScheduleAsync( () => Console.WriteLine("Schedule carbon aware jobs"), DateTimeOffset.Now + TimeSpan.FromHours(2), TimeSpan.FromMinutes(20), TimeSpan.FromMinutes(30), TimeSpan.FromMinutes(5));

Recurring tasks

Setup the maximum execution delay after planned schedule time and the estimated task duration. The extension will do a best effort to get a window with the estimated task duration and minimal grid carbon intensity. When no window can be detected, the task is scheduled as desired.

//use the extension methods IRecurringJobManager manager = GetRecurringJobManager(); manager.AddOrUpdateCarbonAware( "daily", () => Console.WriteLine("Hello, world!"), Cron.Daily, TimeSpan.FromHours(2), TimeSpan.FromMinutes(20)); //or use the static versions CarbonAwareRecurringJob.AddOrUpdate( "daily", () => Console.WriteLine("Hello, world!"), Cron.Daily, TimeSpan.FromHours(2), TimeSpan.FromMinutes(20));

The Hangfire Carbon Aware Extension will prevent the execution of the current instance of the recurring job. It is calculation a execution window with minimal carbon impact and the schedule that task. In the dashboard you will see the notice that the job was executed and a newly planned task.

Fallback

If your computing location is outside Europe or you need other forecasts the WattTime data provider may be useful. You need a valid WattTime account to use the data provider.

builder.Services.AddHangfireCarbonAwareExecution(configuration => configuration .UseCarbonAwareExecution( () => new CarbonAwareExecutionOptions( new CarbonAwareDataProviderWattTime(userName, password), ComputingLocations.Germany)) );

Extensibility

For custom forecasts or scenarios you don't want the build in provider add a own data provider. You may extend the abstract base class CarbonAwareDataProvider or use the CarbonAwareDataProviderWithCustomForecast.

Methodology

Hangfire.CarbonAwareExecution Extension make use of the Carbon Aware SDK a Green Software Foundation Project. There are some extensions to the SDK to use cached offline data sources in our fork.

The emission forecast data are uploaded periodically to a Azure Blob Storage for a given grid region and are public (e.g. for Germany https://carbonawarecomputing.blob.core.windows.net/forecasts/de.json).

For every grid region a data provider is needed:

• Germany: The API from https://www.energy-charts.info/ are used. The data is the share of renewable energy to the total power production. The origin data source is from entso-e. The data is generated every day at 19:00+02 for the next day. After 19:00+02 the maximum forecast is next day 24:00+02.

Other data sources and regions are added soon.