Autofac dependency injection for Azure V2 functions, loosely based on Jason Roberts' https://github.com/introtocomputerscience/azure-function-autofac-dependency-injection package.
Add a startup class to your Function App assembly that implements IWebJobsStartup, and call builder.AddDependencyInjection() from within the Configure method.
using Autofac;
using Microsoft.Azure.WebJobs;
using Microsoft.Azure.WebJobs.Hosting;
using Prabang.Azure.DependencyInjection;
[assembly: WebJobsStartup(typeof(Startup))]
namespace MyApp
{
internal class Startup : IWebJobsStartup
{
public Startup()
{
_myLoggerFactory = new MyLoggerFactory();
}
public void Configure(IWebJobsBuilder builder)
{
builder.AddDependencyInjection(
ConfigureServices,
ConfigureAutofacRegistrations,
ConfigureScopeRegistrations);
}
private void ConfigureAutofacRegistrations(ContainerBuilder cb)
{
var assembly = Assembly.GetExecutingAssembly();
cb.RegisterAssemblyModules(assembly);
}
private void ConfigureServices(IServiceCollection services)
{
services.AddSingleton<ILoggerFactory>(_ => _myLoggerFactory);
}
// This method is called when creating a lifetime scope for the method call. It
// provides an opportunity to add additional registrations that are unique to
// the function invocation.
private void ConfigureScopeRegistrations(ContainerBuilder cb)
{
cb.RegisterType<MyClass>().As<IMyClass>().InstancePerLifetimeScope();
}
}
}Note that the ConfigureServices method is called before the ConfigureAutofacRegistrations method.
To inject a dependency into your Azure Function method, decorate the parameter with an InjectAttribute:
[FunctionName("Test")]
public static async Task<IActionResult> Run(
[HttpTrigger(AuthorizationLevel.Anonymous, "get", "post", Route = null)]HttpRequest req,
[Inject] IHttpSecurityContext securityContext,
ILogger log)
{
}In the above example, the securityContext parameter will be injected with the configured IHttpSecurityContext dependency.