Docket.DotNet Build Image has undocumented limitations

[tyb-dev]

Output of dotnet --info:

.NET SDK:
 Version:   7.0.101
 Commit:    bb24aafa11

Runtime Environment:
 OS Name:     Windows
 OS Version:  10.0.19044
 OS Platform: Windows
 RID:         win10-x64
 Base Path:   C:\Program Files\dotnet\sdk\7.0.101\

Host:
  Version:      7.0.1
  Architecture: x64
  Commit:       97203d38ba

.NET SDKs installed:
  6.0.100 [C:\Program Files\dotnet\sdk]
  7.0.101 [C:\Program Files\dotnet\sdk]

.NET runtimes installed:
  Microsoft.AspNetCore.App 3.1.32 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 5.0.17 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 6.0.0 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 6.0.12 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 7.0.1 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.NETCore.App 3.1.32 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 5.0.17 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 6.0.0 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 6.0.12 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 7.0.1 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.WindowsDesktop.App 3.1.32 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 5.0.17 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 6.0.0 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 6.0.12 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 7.0.1 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]

Other architectures found:
  x86   [C:\Program Files (x86)\dotnet]
    registered at [HKLM\SOFTWARE\dotnet\Setup\InstalledVersions\x86\InstallLocation]

Environment variables:
  Not set

global.json file:
  Not found

Learn more:
  https://aka.ms/dotnet/info

Download .NET:
  https://aka.ms/dotnet/download

What version of Docker.DotNet?:

3.125.14

Steps to reproduce the issue:
Dockerfile

FROM debian
WORKDIR /data
COPY --chmod=+x . /data

Code (ConsoleApp calling BuildImageFromDockerfileAsync)

using Docker.DotNet;
using Docker.DotNet.Models;
using System.Text;
using ICSharpCode.SharpZipLib.Tar;

using var client = new DockerClientConfiguration(new Uri("npipe://./pipe/docker_engine"))
    .CreateClient();

await BuildDockerImage(client, ".");

static async Task BuildDockerImage(DockerClient client, string dockerFileDirectory)
{
    // Create an ImageBuildParameters object
    var buildParameters = new ImageBuildParameters
    {
        Dockerfile = "Dockerfile",
        Remove = true, // Remove intermediate containers after a successful build
        Tags = new[] { "yourimagename:tag" }, // Set your image name and tag
        ForceRemove = true, // Always remove intermediate containers, even upon failure
        NoCache = true // Do not use the cache when building the image,
    };

    // Read the dockerfile content
    var dockerFileContent = File.ReadAllText(Path.Combine(dockerFileDirectory, buildParameters.Dockerfile));

    // Create a tarball with the Dockerfile
    var tarball = new FileStream("new.tar", FileMode.Create);
    await using (var tarArchive = new TarOutputStream(tarball))
    {
        var tarEntry = TarEntry.CreateTarEntry("Dockerfile");
        var fileBytes = Encoding.UTF8.GetBytes(dockerFileContent);
        tarEntry.Size = fileBytes.Length;
        tarArchive.PutNextEntry(tarEntry);
        tarArchive.Write(fileBytes, 0, fileBytes.Length);
        tarArchive.CloseEntry();
    }

    tarball = new FileStream("new.tar", FileMode.Open);

    // Build the image
    await using (var responseStream = await client.Images.BuildImageFromDockerfileAsync(tarball, buildParameters))
    {
        // Read the response from the Docker API
        using var reader = new StreamReader(responseStream);
        while (!reader.EndOfStream)
        {
            var line = await reader.ReadLineAsync();
            Console.WriteLine(line);
        }
    }
}

What actually happened?:

{"errorDetail":{"message":"the --chmod option requires BuildKit. Refer to https://docs.docker.com/go/buildkit/ to learn how to build images with BuildKit enabled"},"error":"the --chmod option requires BuildKit. Refer to https://docs.docker.com/go/buildkit/ to learn how to build images with BuildKit enabled"}

What did you expect to happen?:
Image is created equivalent to doing docker build on the command line.

Additional information:
moby/moby#41711 (comment)

[cdhanna]

I am wondering if this is the same problem causing me difficulties related to multi-architecture builds. If I try to do this in my Dockerfile, I'd expect to get the $BUILDPLATFORM from docker, similar to how it appears via the docker CLI.

FROM --platform=$BUILDPLATFORM mcr.microsoft.com/dotnet/sdk:8.0-alpine AS build-env

According to the docs, that only appears with buildkit.
https://docs.docker.com/reference/dockerfile/#automatic-platform-args-in-the-global-scope

Any ETA on a fix for this? I would love to be able to use buildKit.