Castle Windsor with Azure Functions (v3) - dependency-injection

Question

I'm going around in circles with this. Is there any way to use the Castle Windsor dependency injection adapter (https://github.com/volosoft/castle-windsor-ms-adapter) with Azure Function apps?
The code example on the adaptor github page is for ASP.NET Core but I would have imagined that there'd be a way to specify the service provider used for a function app, too?

Answer 1

There have been no official documents on this but there is a feature request made by DavidJFowler
Please find the sample code from the above feature request.
The IJobActivatorEx implementation:
public class CastleWindsorJobActivator : IJobActivatorEx
{
private readonly WindsorContainer container;
public CastleWindsorJobActivator(WindsorContainer container) => this.container = container;
public T CreateInstance<T>(IFunctionInstanceEx functionInstance)
{
var disposer = functionInstance.InstanceServices.GetRequiredService<ScopeDisposable>();
disposer.Scope = container.BeginScope();
return container.Resolve<T>();
}
// Ensures a created Castle.Windsor scope is disposed at the end of the request
public sealed class ScopeDisposable : IDisposable
{
public IDisposable Scope { get; set; }
public void Dispose() => this.Scope?.Dispose();
}
public T CreateInstance<T>()
{
var disposer = container.Resolve<ScopeDisposable>();
disposer.Scope = container.BeginScope();
return container.Resolve<T>();
}
}
Startup class:
[assembly: FunctionsStartup(typeof(FunctionApp2.Startup))]
namespace FunctionApp2
{
public class Startup: FunctionsStartup
{
public override void Configure(IFunctionsHostBuilder builder)
{
var container = new WindsorContainer();
container.Register(Component.For<IScoped1>().ImplementedBy<Scoped1>().LifestyleScoped())
.Register(Component.For<IScoped2>().ImplementedBy<Scoped2>().LifestyleScoped())
.Register(Component.For<ISingleton1>().ImplementedBy<Singleton1>())
.Register(Component.For<ISingleton2>().ImplementedBy<Singleton2>());
// register function classes in container
var functions = Assembly.GetExecutingAssembly().GetTypes().Where(t =>
t.GetMethods().Any(m => m.GetCustomAttributes(typeof(FunctionNameAttribute), false).Any()));
foreach (var function in functions)
{
container.Register(Component.For(function).LifestyleScoped());
}
builder.Services.AddScoped<CastleWindsorJobActivator.ScopeDisposable>()
.AddSingleton<IJobActivator>(new CastleWindsorJobActivator(container));
container.AddServices(builder.Services);
}
}
}
Example function:
public class Function1
{
public Function1(IScoped1 scoped1, IScoped2 scoped2, ISingleton1 singleton1, ISingleton2 singleton2)
{
}
[FunctionName("Function1")]
public async Task<IActionResult> Run(
[HttpTrigger(AuthorizationLevel.Function, "get", "post", Route = null)] HttpRequest req,
ILogger log)
{
log.LogInformation("C# HTTP trigger function processed a request.");
string name = req.Query["name"];
string requestBody = await new StreamReader(req.Body).ReadToEndAsync();
dynamic data = JsonConvert.DeserializeObject(requestBody);
name = name ?? data?.name;
return name != null
? (ActionResult)new OkObjectResult($"Hello, {name}")
: new BadRequestObjectResult("Please pass a name on the query string or in the request body");
}
}
For now, this feature isn't officially released but you can follow other dependency injection patterns. You can raise a feature request from Microsoft QnA or from Azure Portal.