DI in Azure Functions

Question

I have some class libraries that I use in my ASP.NET Web API app that handle all my backend stuff e.g. CRUD operations to multiple databases like Azure SQL Database, Cosmos

Answer 1

I've seen the willie-zone blog mentioned a lot when it comes to this topic, but you don't need to go that route to use DI with Azure functions.

If you are using Version2 you can make your Azure functions non-static. Then you can add a public constructor for injecting your dependencies. The next step is to add an IWebJobsStartup class. In your startup class you will be able to register your services like you would for any other .Net Core project.

I have a public repo that is using this approach here: https://github.com/jedi91/MovieSearch/tree/master/MovieSearch

Here is a direct link to the startup class: https://github.com/jedi91/MovieSearch/blob/master/MovieSearch/Startup.cs

And here is the function: https://github.com/jedi91/MovieSearch/blob/master/MovieSearch/Functions/Search.cs

Hope this approach helps. If you are wanting to keep your Azure Functions static then the willie-zone approach should work, but I really like this approach and it doesn't require any third party libraries.

One thing to note is the Directory.Build.target file. This file will copy your extensions over in the host file so that DI will work once the function is deployed to Azure. Running the function locally does not require this file.