Adding support for executing functions from referenced assemblies, to the source generated executor implementation.

[kshyju]

Adding support for executing functions from referenced assemblies, to the source generated executor implementation.

Fixes #2030

• Excluding any non public methods when discovering valid azure functions (this change applies to the metadata provider as well).
• Public methods defined inside internal classes from referenced assemblies are using existing reflection based default executor.

Sample code

When tested on a function app which has:

• 1 http function (Function1) defined in the project.
• Has a nuget reference to Microsoft.Azure.Functions.Worker.Extensions.OpenApi 1.5.1 package, which will add 4 functions.
• Has a project reference which has 3 functions.
  - 1 Internal class with 2 functions (1 public method(FooLibraryInternalClassPublicMethod1) and 1 internal method(FooLibraryInternalClassInternalMethod2)
  - 1 Public class with 1 public method (FooLibraryPublicClassPublicMethod1).

internal class DirectFunctionExecutor : IFunctionExecutor
{
    private readonly IFunctionActivator _functionActivator;
    private Lazy<IFunctionExecutor> _defaultExecutor;
    private readonly Dictionary<string, Type> types = new()
    {
        { "FunctionApp172.Function1", Type.GetType("FunctionApp172.Function1, FunctionApp172, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null")! },
        { "Microsoft.Azure.Functions.Worker.Extensions.OpenApi.DefaultOpenApiHttpTrigger", Type.GetType("Microsoft.Azure.Functions.Worker.Extensions.OpenApi.DefaultOpenApiHttpTrigger, Microsoft.Azure.Functions.Worker.Extensions.OpenApi, Version=1.0.0.0, Culture=neutral, PublicKeyToken=9475d07f10cb09df")! },
        { "ClassLibrary8.FooLibraryInternalClass", Type.GetType("ClassLibrary8.FooLibraryInternalClass, ClassLibrary8, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null")! },
        { "ClassLibrary8.FooLibraryPublicClass", Type.GetType("ClassLibrary8.FooLibraryPublicClass, ClassLibrary8, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null")! }
    };

    public DirectFunctionExecutor(IFunctionActivator functionActivator)
    {
        _functionActivator = functionActivator ?? throw new ArgumentNullException(nameof(functionActivator));
    }

    /// <inheritdoc/>
    public async ValueTask ExecuteAsync(FunctionContext context)
    {
        var inputBindingFeature = context.Features.Get<IFunctionInputBindingFeature>()!;
        var inputBindingResult = await inputBindingFeature.BindFunctionInputAsync(context)!;
        var inputArguments = inputBindingResult.Values;
        _defaultExecutor = new Lazy<IFunctionExecutor>(() => CreateDefaultExecutorInstance(context));

        if (string.Equals(context.FunctionDefinition.EntryPoint, "FunctionApp172.Function1.Run", StringComparison.Ordinal))
        {
            var instanceType = types["FunctionApp172.Function1"];
            var i = _functionActivator.CreateInstance(instanceType, context) as global::FunctionApp172.Function1;
            context.GetInvocationResult().Value = i.Run((global::Microsoft.Azure.Functions.Worker.Http.HttpRequestData)inputArguments[0]);
        }
        else if (string.Equals(context.FunctionDefinition.EntryPoint, "Microsoft.Azure.Functions.Worker.Extensions.OpenApi.DefaultOpenApiHttpTrigger.RenderSwaggerDocument", StringComparison.Ordinal))
        {
            var instanceType = types["Microsoft.Azure.Functions.Worker.Extensions.OpenApi.DefaultOpenApiHttpTrigger"];
            var i = _functionActivator.CreateInstance(instanceType, context) as global::Microsoft.Azure.Functions.Worker.Extensions.OpenApi.DefaultOpenApiHttpTrigger;
            context.GetInvocationResult().Value = await i.RenderSwaggerDocument((global::Microsoft.Azure.Functions.Worker.Http.HttpRequestData)inputArguments[0], (string)inputArguments[1], (global::Microsoft.Azure.Functions.Worker.FunctionContext)inputArguments[2]);
        }
        else if (string.Equals(context.FunctionDefinition.EntryPoint, "Microsoft.Azure.Functions.Worker.Extensions.OpenApi.DefaultOpenApiHttpTrigger.RenderOpenApiDocument", StringComparison.Ordinal))
        {
            var instanceType = types["Microsoft.Azure.Functions.Worker.Extensions.OpenApi.DefaultOpenApiHttpTrigger"];
            var i = _functionActivator.CreateInstance(instanceType, context) as global::Microsoft.Azure.Functions.Worker.Extensions.OpenApi.DefaultOpenApiHttpTrigger;
            context.GetInvocationResult().Value = await i.RenderOpenApiDocument((global::Microsoft.Azure.Functions.Worker.Http.HttpRequestData)inputArguments[0], (string)inputArguments[1], (string)inputArguments[2], (global::Microsoft.Azure.Functions.Worker.FunctionContext)inputArguments[3]);
        }
        else if (string.Equals(context.FunctionDefinition.EntryPoint, "Microsoft.Azure.Functions.Worker.Extensions.OpenApi.DefaultOpenApiHttpTrigger.RenderSwaggerUI", StringComparison.Ordinal))
        {
            var instanceType = types["Microsoft.Azure.Functions.Worker.Extensions.OpenApi.DefaultOpenApiHttpTrigger"];
            var i = _functionActivator.CreateInstance(instanceType, context) as global::Microsoft.Azure.Functions.Worker.Extensions.OpenApi.DefaultOpenApiHttpTrigger;
            context.GetInvocationResult().Value = await i.RenderSwaggerUI((global::Microsoft.Azure.Functions.Worker.Http.HttpRequestData)inputArguments[0], (global::Microsoft.Azure.Functions.Worker.FunctionContext)inputArguments[1]);
        }
        else if (string.Equals(context.FunctionDefinition.EntryPoint, "Microsoft.Azure.Functions.Worker.Extensions.OpenApi.DefaultOpenApiHttpTrigger.RenderOAuth2Redirect", StringComparison.Ordinal))
        {
            var instanceType = types["Microsoft.Azure.Functions.Worker.Extensions.OpenApi.DefaultOpenApiHttpTrigger"];
            var i = _functionActivator.CreateInstance(instanceType, context) as global::Microsoft.Azure.Functions.Worker.Extensions.OpenApi.DefaultOpenApiHttpTrigger;
            context.GetInvocationResult().Value = await i.RenderOAuth2Redirect((global::Microsoft.Azure.Functions.Worker.Http.HttpRequestData)inputArguments[0], (global::Microsoft.Azure.Functions.Worker.FunctionContext)inputArguments[1]);
        }
        else if (string.Equals(context.FunctionDefinition.EntryPoint, "ClassLibrary8.FooLibraryInternalClass.Run1", StringComparison.Ordinal))
        {
            await _defaultExecutor.Value.ExecuteAsync(context);
        }
        else if (string.Equals(context.FunctionDefinition.EntryPoint, "ClassLibrary8.FooLibraryPublicClass.Run1", StringComparison.Ordinal))
        {
            var instanceType = types["ClassLibrary8.FooLibraryPublicClass"];
            var i = _functionActivator.CreateInstance(instanceType, context) as global::ClassLibrary8.FooLibraryPublicClass;
            context.GetInvocationResult().Value = i.Run1((global::Microsoft.Azure.Functions.Worker.Http.HttpRequestData)inputArguments[0]);
        }
    }

    private IFunctionExecutor CreateDefaultExecutorInstance(FunctionContext context)
    {
        var defaultExecutorFullName = "Microsoft.Azure.Functions.Worker.Invocation.DefaultFunctionExecutor, Microsoft.Azure.Functions.Worker.Core, Version=1.16.0.0, Culture=neutral, PublicKeyToken=551316b6919f366c";
        var defaultExecutorType = Type.GetType(defaultExecutorFullName);

        return ActivatorUtilities.CreateInstance(context.InstanceServices, defaultExecutorType) as IFunctionExecutor;
    }
}

Pull request checklist

• My changes do not require documentation changes
  • Otherwise: Documentation issue linked to PR
• My changes should not be added to the release notes for the next release
  • Otherwise: I've added my notes to release_notes.md
• My changes do not need to be backported to a previous version
  • Otherwise: Backport tracked by issue/PR #issue_or_pr
• I have added all required tests (Unit tests, E2E tests)