BadImageFormatException when using serverless.AspNetCoreWebApp template with Mock Lambda Test Tool

[coultonluke]

Description

Can't make request to lambda using Mock Lambda Test Tool when project has reference to Microsoft.AspNetCore.Mvc.Razor.RuntimeCompilation Nuget package.

Reproduction Steps

1. Install templates: dotnet new -i "Amazon.Lambda.Templates::*"

2. Create new project: dotnet new serverless.AspNetCoreWebApp

3. Add Nuget reference to Microsoft.AspNetCore.Mvc.Razor.RuntimeCompilation

4. Edit ConfigureServices in startup to enable razor pages to be loaded:

    public void ConfigureServices(IServiceCollection services)
    {
        services.AddControllers();
        var builder = services.AddRazorPages();
        builder.AddRazorRuntimeCompilation();
    }
   

5. Configure debug configuration for mock test tool as shown in the readme for Rider:
   Executable and executable path: "\.dotnet\tools\.store\amazon.lambda.testtool-3.1\0.11.4\amazon.lambda.testtool-3.1\0.11.4\tools\netcoreapp3.1\any\Amazon.Lambda.TestTool.BlazorTester.dll"

6. Create a controller and use attribute routing

7. Debug application and send in request using Mock Test Tool blazor interface

Request I'm using: { "httpMethod": "GET", "path": "/api/Home" }

Without Nuget reference:

With Nuget reference:

Logs

Environment

• Build Version: Amazon.Lambda.AspNetCoreServer 7.0.1
• OS Info: Windows 10
• Build Environment: Jetbrains Rider
• Targeted .NET Platform: netcoreapp3.1

Resolution

• Remove reference to Microsoft.AspNetCore.Mvc.Razor.RuntimeCompilation (no use for local debugging)

A similar issue also happens when I reference Microsoft.AspNetCore.Mvc.WebApiCompatShim too, but the error is that it can't find System.Json.

---

This is a 🐛 bug-report

[ashishdhingra]

Hi @coultonluke,

Good morning.

I was able to reproduce the issue in Visual Studio (not Jetbrains Rider) by:

• Creating serverless.AspNetCoreWebApp project
• Adding reference to Microsoft.AspNetCore.Mvc.Razor.RuntimeCompilation version 3.1.22 (since this is the latest version compatible with NetCoreApp31)
• Enabling controller endpoints (endpoints.MapControllers();)
• Adding a minimal HomeController:

[Route("api/[controller]")]
public class HomeController : Controller
{
    [HttpGet]
    public string Index()
    {
        return "Hello";
    }
}

• Debug using Mock Lambda Test Tool.

I manually tried adding reference to Microsoft.CSharp 4.0.0 NuGet package, however, it gave the warning NU1701 | Package 'Microsoft.CSharp 4.0.0' was restored using '.NETFramework,Version=v4.6.1, .NETFramework,Version=v4.6.2, .NETFramework,Version=v4.7, .NETFramework,Version=v4.7.1, .NETFramework,Version=v4.7.2, .NETFramework,Version=v4.8' instead of the project target framework '.NETCoreApp,Version=v3.1'. This package may not be fully compatible with your project..

Kindly note that Mock Lambda Test Tool uses reflection to load all the dependent assemblies. I'm unsure if Microsoft.AspNetCore.Mvc.Razor.RuntimeCompilation tries to load Microsoft.CSharp 4.0.0 at runtime in a different context.

Thanks,
Ashish

[coultonluke]

Thank you for looking into this for me. I appreciate it. I'm trying to get going with the Lambda Test Tool using an existing project, so do you think I'll just have to remove that reference and it's functionality in order to use the tool?

[ashishdhingra]

Thank you for looking into this for me. I appreciate it. I'm trying to get going with the Lambda Test Tool using an existing project, so do you think I'll just have to remove that reference and it's functionality in order to use the tool?

@coultonluke Removing that reference resolves the issue. I would have team look at this issue to see if something could be done, before deciding to close the issue.

[coultonluke]

Are razor views generally supported when using the Lambda Test Tool even without the Microsoft.AspNetCore.Mvc.Razor.RuntimeCompilation reference?

I've created a basic project in the same way and the views work completely fine when running as a normal project, but when I use the Lambda Test Tool the Views cannot be found. I've tried setting a ContentRootPath and also setting them to copy but to no avail.

Repository ==> https://github.com/coultonluke/riderlambdatest.git

I thought I knew a thing or two about .NET Core MVC as I use it every day, but this stuff is leaving me stumped cause even basic stuff isn't working. Perhaps it's my own fault for sticking with 3.1 for soo long 😂

[ashishdhingra]

{ "httpMethod": "GET", "path": "/api/Home" }

@coultonluke I'm unsure why you are using Mock Lambda Test tool to test the Razor pages. Mock Lambda Test tool is ideal for testing simple Lambda functions and API requests. Example Requests dropdown in the tool provides a good reference for the JSON to be used for common requests. Normal razor pages could be tested in IIS/IIS Express environment.

[coultonluke]

Its because I'm wanting to host my existing website MVC application in AWS Lambda. When I run the lambda in AWS Lambda it returns views just fine, but I am struggling to replicate it locally using the test tool. I want to be able to debug any issues that are faced by running the LambdaEntryPoint as would be running in the real environment.

I was just looking at the code base and I was going to suggest adding an example ALB request to the list of common request types. The Amazon.Lambda.AspNetCoreServer supports ApplicationLoadBalancerFunction but there is no test request for it from what I can see? I was thinking this might be a useful pull request to add a request like the example request provided in the documentation.

I see what you're saying, but even with an API endpoint you could just use normal debugging and postman or whatever to test requests, you don't need to use the Mock Lambda Test Tool, but the test tool is intended to test it and return the response as if it were hosted in lambda?

[ashishdhingra]

provided in the documentation

@coultonluke Thanks for your reply. As pointed out earlier, Mock Lambda test tool is not suitable for testing Razor pages; local IIS/IIS Express testing could be used to test Razor pages.

As far as adding an example ALB request to the list of common request types is concerned, it could be a good candidate for feature request. Feel free to test and submit a PR for review if possible, which could then be reviewed by the team.

Also refer Lambda Test Tool Readme for additional details and Known Limitations.

[coultonluke]

Thank you again. I will look into posting a pull request.

I must be misunderstanding the need for the tool somewhat I suppose, because it seems like an odd limitation for the tool to care what is returned back from an API request as long as there is something that was returned, whether the body is HTML or JSON should it matter when you're essentially working with a web app?

The important thing for me is to be able to debug it as if it were in the lambda environment, I'm not the only one returning HTML back from a lambda surely 😐. I think the BBC have all of their sites hosted in lambda nowadays.

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[coultonluke]

I didn't mean to press close. I have reopened this.

[coultonluke]

@ashishdhingra After some sleep I think I understand what you're saying now. Are you saying that I can still debug through the code even if I don't have the view coming back in the lambda test tool? If that's the case then I do agree, it's not that important to be able to see the response back in the blazor app really. It just surprised me that it's a limitation. Thanks again

[Pankraty]

This issues strikes us as well. We are creating a lambda function for building emails and for that, we are using Razor as a templating engine. Unfortunately, this does not work well with the test tool as we getting the same exception as described in the issue. The fix would be deeply appreciated!

[ashishdhingra]

@coultonluke Good morning. I was reviewing old open issues and came across this one. The issue doesn't appear to be reproducible using latest .NET 8 AWS serverless template. Below is the code.
.csproj

<Project Sdk="Microsoft.NET.Sdk.Web">
  <PropertyGroup>
    <OutputType>Exe</OutputType>
    <TargetFramework>net8.0</TargetFramework>
    <ImplicitUsings>enable</ImplicitUsings>
    <Nullable>enable</Nullable>
    <GenerateRuntimeConfigurationFiles>true</GenerateRuntimeConfigurationFiles>
    <AWSProjectType>Lambda</AWSProjectType>
    <!-- This property makes the build directory similar to a publish directory and helps the AWS .NET Lambda Mock Test Tool find project dependencies. -->
    <CopyLocalLockFileAssemblies>true</CopyLocalLockFileAssemblies>
    <!-- Generate ready to run images during publishing to improve cold start time. -->
    <PublishReadyToRun>true</PublishReadyToRun>
  </PropertyGroup>
  <ItemGroup>
    <PackageReference Include="Amazon.Lambda.AspNetCoreServer" Version="9.0.0" />
    <PackageReference Include="Microsoft.AspNetCore.Mvc.Razor.RuntimeCompilation" Version="8.0.10" />
  </ItemGroup>
  <ItemGroup>
    <Folder Include="wwwroot\images\" />
  </ItemGroup>
</Project>

Startup.cs

namespace AWSServerlessNet8;

public class Startup
{
    public Startup(IConfiguration configuration)
    {
        Configuration = configuration;
    }

    public IConfiguration Configuration { get; }

    // This method gets called by the runtime. Use this method to add services to the container.
    public void ConfigureServices(IServiceCollection services)
    {
        services.AddControllers();
        services.AddMvc(o => o.EnableEndpointRouting = false);
        var builder = services.AddRazorPages();
        builder.AddRazorRuntimeCompilation();
    }

    // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
    public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
    {
        if (env.IsDevelopment())
        {
            app.UseDeveloperExceptionPage();
        }
        else
        {
            app.UseExceptionHandler("/Error");
            // The default HSTS value is 30 days. You may want to change this for production scenarios, see https://aka.ms/aspnetcore-hsts.
            app.UseHsts();
        }

        app.UseHttpsRedirection();
        app.UseStaticFiles();

        app.UseRouting();

        app.UseAuthorization();
        app.UseMvc();

        app.UseEndpoints(endpoints =>
        {
            endpoints.MapRazorPages();
        });
    }
}

Controllers\HomeController.cs

using Microsoft.AspNetCore.Mvc;

namespace AWSServerlessNet8.Controllers
{
    [Route("[controller]")]
    public class HomeController : Controller
    {
        [HttpGet]
        public string Index()
        {
            return "Hello";
        }
    }
}

Debugging using latest version 0.15.2 of Mock Lambda test tool and input { "httpMethod": "GET", "path": "/Home" } appears to work fine:

Please verify the same at your end and confirm if this issue could be closed.

Thanks,
Ashish

[coultonluke]

I have just been looking at this again. I've got it set up from the template with an MVC controller, but returning HTML instead of JSON in the result still results in an error when using the test tool.

I want to return HTML, because I am hosting a website in lambda, as previously discussed, it seems like an odd limitation for it not to work just because it's an MVC controller and HTML is returned, when it's just a string returned in the "body" property of the JSON. The body should be able to be any string, whether it's HTML or JSON.

Thanks for looking into this.

[coultonluke]

Just so I'm clear on it. I can confirm that the inclusion of that Nuget package no longer causes and error when calling an API controller. So that's good!

But returning a view response from an MVC controller results in an error.

[ashishdhingra]

@coultonluke Thanks for your response. As mentioned earlier in #1075 (comment), the Lambda Test Tool is suitable for testing simple Lambda functions and API requests. From your error stack trace, looks like ASP.NET Razor engine is unable to find the assembly, perhaps because the current directory is the Lambda tools installation directory. We could try setting the current directory to project directory, but unsure if it would work due to the limitation mentioned in #1482 (comment), where we cannot create more than one AppDomain in .NET Core and later.

I would advise you to open a new feature request mentioning all the details which could be reviewed with the team.

Thanks,
Ashish

[coultonluke]

Sorry to be a pain, I hope this comes across the right way - but surely the point in the test tool is be able to run any endpoint and to see the response as if it were running in the AWS lambda environment?

If I return a random string from it, or HTML, the string shouldn't matter, right? When you return an MVC response from a lambda, you'd still want to see the response that the lambda will return. Whether that be headers, a HTML string or base64 etc etc. If it would work in lambda, then it should work in the test tool right?

As mentioned I will take your advice and raise another ticket if you don't think it's covered within this one.

[ashishdhingra]

Sorry to be a pain, I hope this comes across the right way - but surely the point in the test tool is be able to run any endpoint and to see the response as if it were running in the AWS lambda environment?

If I return a random string from it, or HTML, the string shouldn't matter, right? When you return an MVC response from a lambda, you'd still want to see the response that the lambda will return. Whether that be headers, a HTML string or base64 etc etc. If it would work in lambda, then it should work in the test tool right?

As mentioned I will take your advice and raise another ticket if you don't think it's covered within this one.

@coultonluke I understand the concern, but the error is thrown by ASP.NET runtime unable to find assemblies and the possible reason might be the design of Lambda Test Tool where it loads project assemblies at runtime. There is some work being done to make test tool better, hence it would be better to open a new feature request to get it reviewed by the team. We would look forward for the feature request.

Thanks,
Ashish

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