do not merge: wslc compose POC by OneBlue · Pull Request #41378 · microsoft/WSL

Blue (OneBlue) · 2026-08-19T00:47:26Z

Summary of the Pull Request

This change is a very simplified implementation for wslc compose. With this, a simple compose.yml file like this runs successfully:

services:
  photoprism:
    image: photoprism/photoprism:latest
    ports:
      - "2342:2342"
    environment:
      PHOTOPRISM_ADMIN_USER: "admin"                 # admin login username
      PHOTOPRISM_ADMIN_PASSWORD: "insecure"          # initial admin password (8-72 characters)
      PHOTOPRISM_AUTH_MODE: "password"               # authentication mode (public, password)
      PHOTOPRISM_DATABASE_DRIVER: "mysql"            # MariaDB 10.5.12+ (MySQL successor) offers significantly better performance compared to SQLite
      PHOTOPRISM_DATABASE_SERVER: "mariadb:3306"     # MariaDB database server (hostname:port)
      PHOTOPRISM_DATABASE_NAME: "photoprism"         # MariaDB database, see MARIADB_DATABASE in the mariadb service
      PHOTOPRISM_DATABASE_USER: "photoprism"         # MariaDB database username, must be the same as MARIADB_USER
      PHOTOPRISM_DATABASE_PASSWORD: "sample-password"       # MariaDB database password, must be the same as MARIADB_PASSWORD
    working_dir: "/photoprism"  
  mariadb:
    image: mariadb:12.3
    environment:
      MARIADB_AUTO_UPGRADE: "1"
      MARIADB_DATABASE: "photoprism"
      MARIADB_USER: "photoprism"
      MARIADB_PASSWORD: "sample-password"
      MARIADB_ROOT_PASSWORD: "sample-password"

PR Checklist

Closes: Link to issue #xxx
Communication: I've discussed this with core contributors already. If work hasn't been agreed, this work might be rejected
Tests: Added/updated if needed and all pass
Localization: All end user facing strings can be localized
Dev docs: Added/updated if needed
Documentation updated: If checked, please file a pull request on our docs repo and link it here: #xxx

Detailed Description of the Pull Request / Additional comments

Validation Steps Performed

Copilot

Pull request overview

This PR introduces a proof-of-concept wslc compose command and a minimal backing service-side compose session object, along with tests and supporting plumbing (session helpers, CLI wiring, and MSI/IDL updates).

Changes:

Add a new compose command tree (create/up/start/attach/stop) and a CLI service implementation to drive compose sessions.
Add an IWSLCComposeSession COM interface plus a minimal WSLCComposeSession implementation and IWSLCSession::CreateComposeSession.
Add new Windows tests for compose, and refactor shared WSLC test helpers into test/windows/Common.*.

Reviewed changes

Copilot reviewed 23 out of 23 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
test/windows/WSLCTests.cpp	Refactors session/image setup to shared test helpers.
test/windows/WSLCComposeTests.cpp	Adds new TAEF tests covering compose session lifecycle and container name networking.
test/windows/wslc/WSLCCLICommandUnitTests.cpp	Adds a unit test verifying the compose subcommand tree.
test/windows/Common.h	Declares new shared WSLC test helper APIs in `wsl::test`.
test/windows/Common.cpp	Implements shared WSLC test helpers (session creation, default settings, load images).
test/windows/CMakeLists.txt	Adds `WSLCComposeTests.cpp` to the Windows test build.
src/windows/wslcsession/WSLCSession.h	Adds compose session entry points and supporting internals to `WSLCSession`.
src/windows/wslcsession/WSLCSession.cpp	Implements `CreateComposeSession` and compose container creation; refactors pull-image internals.
src/windows/wslcsession/WSLCComposeSession.h	Introduces the COM class implementing `IWSLCComposeSession`.
src/windows/wslcsession/WSLCComposeSession.cpp	Implements the minimal compose session methods (list/start/stop; attach stubbed).
src/windows/wslcsession/CMakeLists.txt	Adds new sources/headers and links `yaml-cpp` for compose parsing support.
src/windows/wslc/services/ConsoleService.h	Adds an overload to relay non-tty output to provided handles.
src/windows/wslc/services/ConsoleService.cpp	Implements the new overload and makes stdout/stderr relays conditional.
src/windows/wslc/services/ComposeService.h	Adds a CLI-side compose service wrapper.
src/windows/wslc/services/ComposeService.cpp	Implements CLI-side compose operations (create/up/start/attach/stop).
src/windows/wslc/commands/RootCommand.cpp	Registers `compose` under the root command.
src/windows/wslc/commands/ComposeCommand.h	Declares the compose command hierarchy.
src/windows/wslc/commands/ComposeCommand.cpp	Implements compose commands and argument plumbing.
src/windows/service/inc/wslc.idl	Adds `IWSLCComposeSession` and `IWSLCSession::CreateComposeSession`.
src/windows/common/WSLCContainerLauncher.h	Exposes reusable option-storage creation for container launchers.
src/windows/common/WSLCContainerLauncher.cpp	Refactors container option building into `CreateOptions()` to preserve pointer lifetimes.
msipackage/package.wix.in	Registers the new compose session interface IID.
localization/strings/en-US/Resources.resw	Adds localized strings for compose command help/args and an invalid-file error message.

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    # Session and container implementation
+    ComposeSpec.cpp
+    ServiceContainerLauncher.cpp
    WSLCSession.cpp
    WSLCSessionRuntime.cpp
+    WSLCComposeSession.cpp
    WSLCContainer.cpp


+int ComposeService::Attach(Terminal& Terminal, models::Session& Session, const std::wstring& Path)
+{
+    [[maybe_unused]] auto operation = Session.BeginContainerOperation();
+    auto composeSession = Open(Session, Path);


+HRESULT WSLCComposeSession::Attach()
+{
+    // TODO
+    return S_OK;
+}


+        VERIFY_SUCCEEDED(composeSession->Attach());
+        VERIFY_SUCCEEDED(composeSession->Stop(10));


Copilot

Pull request overview

Copilot reviewed 27 out of 27 changed files in this pull request and generated 1 comment.

Suppressed comments (3)

src/windows/wslcsession/ComposeSpec.cpp:223

YAML::LoadFile is called with Path.string(), which can corrupt non-ASCII/Unicode Windows paths (and fail to open the compose file). Use an explicit UTF-8 conversion for the filesystem path before passing it to yaml-cpp.

    ComposeSpec ParseComposeFile(const std::filesystem::path& Path)
    {
        const auto root = YAML::LoadFile(Path.string());
        const auto services = root["services"];
        if (!services || !services.IsMap() || services.size() == 0)
        {
            ThrowInvalidComposeFile(Path, L"the file must contain a non-empty services map");
        }

src/windows/wslcsession/ComposeSpec.cpp:358

ComposeSpec::Parse can reach the end of a non-void function without an explicit return, which can trigger build warnings (and some toolchains treat it as an error) even though ThrowInvalidComposeFile is [[noreturn]]. Add an explicit unreachable/return after the catch to make control-flow obvious to the compiler.

ComposeSpec ComposeSpec::Parse(const std::filesystem::path& Path)
{
    try
    {
        return ParseComposeFile(Path);
    }
    catch (const YAML::Exception& exception)
    {
        ThrowInvalidComposeFile(Path, wsl::shared::string::MultiByteToWide(exception.what()));
    }
}

src/windows/wslc/services/ComposeService.cpp:80

ComposeService::Attach unconditionally adds relay handles for stdout/stderr even if the container attach call returned null/invalid handles. ConsoleService::RelayNonTtyProcess was updated to guard against missing stdout/stderr, so this path should do the same to avoid relaying from invalid handles.

        THROW_IF_FAILED(container->Attach(nullptr, &stdinHandle, &stdoutHandle, &stderrHandle));

        // TODO: Add support for stdin, tty processes, stop on ctrl-c.

        io.AddHandle(std::make_unique<wsl::windows::common::io::RelayHandle<wsl::windows::common::io::ReadHandle>>(
            stdoutHandle.Release(), GetStdHandle(STD_OUTPUT_HANDLE)));

        io.AddHandle(std::make_unique<wsl::windows::common::io::RelayHandle<wsl::windows::common::io::ReadHandle>>(
            stderrHandle.Release(), GetStdHandle(STD_ERROR_HANDLE)));
    }

+    std::string networkName = Spec.ProjectName + "_default"; // TODO: Implement this properly.
+
+    // Create a network for the compose session.
+    // TODO: open an existing network instead of deleting.
+
+    auto networkCleanup = DeleteNetworkImpl(networkName.c_str());
+    THROW_HR_IF_MSG(
+        networkCleanup,
+        FAILED(networkCleanup) && networkCleanup != WSLC_E_NETWORK_NOT_FOUND,
+        "Failed to delete network %hs",
+        networkName.c_str());
+
+    WSLCNetworkOptions networkOptions{};
+    networkOptions.Name = networkName.c_str();
+    THROW_IF_FAILED(CreateNetworkImpl(&networkOptions));
+


Blue (OneBlue) added 10 commits August 17, 2026 09:04

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Merge remote-tracking branch 'origin/master' into user/oneblue/compose

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Copilot AI lite review requested due to automatic review settings August 19, 2026 00:47

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do not merge: wslc compose POC - #41378

do not merge: wslc compose POC#41378
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		VERIFY_SUCCEEDED(composeSession->Attach());
		VERIFY_SUCCEEDED(composeSession->Stop(10));

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Blue (OneBlue) commented Aug 19, 2026

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