In .NET Core you can use Worker Services to create long-running services.
There are numerous reasons for creating long-running services such as:
- Processing CPU intensive data.
- Queuing work items in the background.
- Performing a time-based operation on a schedule.
Through the Worker Service you can create cross platform background services that can be run as a Windows Service on Windows or a Systemd daemon in Linux.
You can create a worker service through:
or through the Visual Studio IDE:
Use a Worker Service for scheduled batch processing
At one of my clients, we typically didn’t use Worker Services for batch processing. Instead we used Console applications together with the Windows Task Scheduler. The advantage of this approach is that we didn’t need to write any scheduling logic and could use all the features and monitoring available through the built-in Task Scheduler.
However a disadvantage of this approach is that we couldn’t take advantage of the HostedService features. With hosted services you get logging, configuration, and dependency injection (DI) for free and you can take advantage of all libraries that work with the generic host and the knowledge that you already have from building ASP.NET Core applications.
The problem of Worker Services is that there are out-of-the-box setup to be always running and to never quit.
What if we could combine the advantages of the HostedService but stop it when the batch job has completed?
Let’s see how we can get this done…
When you create a new worker service, you get a Program.cs file that configures a Worker BackgroundService
And the Worker class itself where you can do the work:
By default stopping the Worker will not stop the service host. The trick to shutdown the application after the batch job has completed is to inject the IHostApplicationLifetime and call StopApplication() when the work is done:
You can further improve this by adding exception handling and cancellation support but I leave that up to you…