Add AzureFunctionsEndToEnd with prototype implementation

[captainsafia]

This PR introduces an AzureFunctionsEndToEnd sample application with prototype implementations of certain APIs:

• APIs that currently target IHostApplicationBuilder have been reimplemented to target HostBuilder. This should be addressed on Azure Functions supports IHostApplicationBuilder.
• A custom AzureFunctionsProjectResource has been included that launches the func host as an executable resource. This is a temporary implementation until we support modeling a Functions application as a project resource. These APIs are formally proposed in Add AzureFunctionsProjectResource and extension methods #5412. Support for mocking the Functions app as a project resource can be added by updating the mock API definitions as follows:

public class AzureFunctionsProjectResource(string name) 
    : ProjectResource(name), IResourceWithEnvironment, IResourceWithArgs, IResourceWithServiceDiscovery { }

public static class AzureFunctionsProjectResourceExtensions
  public static IResourceBuilder<FunctionAppResource> AddAzureFunctionsProject<TProject>(this IDistributedApplicationBuilder builder, string name) where TProject : IProjectMetadata, new()
    {
        var projectDirectory = Path.GetDirectoryName(new TProject().ProjectPath)!;
        var resource = new AzureFunctionsProjectResource(name);
        return builder.AddResource(resource)
            .WithAnnotation(new TProject())
            .WithHttpEndpoint(name: "http", env: "AZFUNCHOSTPORT")
            .WithEnvironment("FUNCTIONS_WORKER_RUNTIME", "dotnet-isolated")
            .WithEnvironment("OTEL_DOTNET_EXPERIMENTAL_OTLP_EMIT_EXCEPTION_LOG_ATTRIBUTES", "true")
            .WithEnvironment("OTEL_DOTNET_EXPERIMENTAL_OTLP_EMIT_EVENT_LOG_ATTRIBUTES", "true")
            .WithEnvironment("OTEL_DOTNET_EXPERIMENTAL_OTLP_RETRY", "in_memory")
            .WithEnvironment("ASPNETCORE_FORWARDEDHEADERS_ENABLED", "true")
            .WithEnvironment("FUNCTIONS_WORKER_RUNTIME", "dotnet-isolated")
            .WithOtlpExporter()
            .WithManifestPublishingCallback(async (context) => {
                context.Writer.WriteString("type", "function.v0");
                context.Writer.WriteString("path", context.GetManifestRelativePath(new TProject().ProjectPath));
                await context.WriteEnvironmentVariablesAsync(resource);
                context.Writer.WriteStartObject("bindings");
                foreach (var s in new string[]{ "http", "https"}) {
                    context.Writer.WriteStartObject(s);
                    context.Writer.WriteString("scheme", s);
                    context.Writer.WriteString("protocol", "tcp");
                    context.Writer.WriteString("transport", "http");
                    context.Writer.WriteBoolean("external", true);
                    context.Writer.WriteEndObject();
                }
                context.Writer.WriteEndObject();
            });
    }
}

And making the following changes to AzureFunctionsEndToEnd.Functions.csproj:

  <PropertyGroup>
    <RunCommand>func</RunCommand>
    <RunArguments>start --no-build --csharp --verbose --worker-runtime dotnetIsolated --port $(AZFUNCHOSTPORT)</RunArguments>
     <RunWorkingDirectory>bin/output</RunWorkingDirectory>
  </PropertyGroup>

• A custom WithReference implementation is implemented to support mapping resource strings as needed until Add support for IResourceWithAzureFunctionsConfig interface #5408 is implemented.

Microsoft Reviewers: Open in CodeFlow

Fixes #5412
Fixes #5408

[radical]

A test should be added for this too, see #5316 for an example.

[davidfowl]

I'm not sure we want to test this sample yet. This is part of bootstrapping the azure functions work.

[eerhardt]

How come this is here and not in .AddServiceDefaults?

[davidfowl]

IHostBuilder vs IHostApplicationBuilder

[eerhardt]

AddServiceDefaults (called above) is also implemented in terms of IHostBuilder. It is in the HostBuilderExtensions.cs file.

[captainsafia]

/azp run

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[captainsafia]

/azp run

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[captainsafia]

/azp run

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[captainsafia]

/azp run

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[captainsafia]

/azp run

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[captainsafia]

/azp run

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[captainsafia]

/azp run

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[dciborow]

standing by ready for to do some testing on our internal project once this is released. Please feel free to reach out - dciborow.

[captainsafia]

/azp run

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Azure Pipelines successfully started running 1 pipeline(s).

[captainsafia]

standing by ready for to do some testing on our internal project once this is released. Please feel free to reach out - dciborow.

Great to hear! I'll give the README another run through today to make sure we've captured all the limitations/setup instructions correctly. This is just the first part of the integration and there will be a few kinks to iron out. 😅