Add --iidfile to wslc image build

[ggarzia-MSFT]

Summary of the Pull Request

Adds a --iidfile <path> option to wslc build, mirroring docker build --iidfile. After a successful build, the resulting image ID is written to the given file. The file is created/truncated up front (so a bad path fails fast before the long build runs) and is removed if the build fails, so a failed build never leaves a stale file behind.

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

• CLI argument: New iidfile value argument registered in ArgumentDefinitions.h and wired into the build command. Its description string (WSLCCLI_IidFileArgDescription) is added to Resources.resw for localization.
• RAII helper (IidFile): New ImageModel.{h,cpp} introduces a models::IidFile class that:
  • Opens the file with CREATE_ALWAYS at construction so an invalid path surfaces an error before the build starts (matching docker build), throwing a localized user error on failure.
  • Writes the image ID on Commit().
  • Deletes the file on destruction if Commit() was never called, so a failed/cancelled build leaves no file behind.
  • Is NON_COPYABLE / NON_MOVABLE.
• Service/session plumbing: ImageService::Build now returns the image ID string. A new WSLCBuildImageFlagsReturnImageId flag is set only when --iidfile is supplied, and the server (WSLCSession) returns the image ID via a new out-parameter on BuildImage (IDL updated in wslc.idl / WSLCShared.idl). ImageTasks.cpp orchestrates: create the IidFile, run the build, then Commit() the returned ID.

Validation Steps Performed

• Unit tests: Updated test/windows/WSLCTests.cpp for the new flag/out-parameter and image-ID return path.
• E2E tests: Added coverage in test/windows/wslc/e2e/WSLCE2EImageBuildTests.cpp exercising wslc build --iidfile, verifying the file contains the built image ID and that a failed build does not leave the file behind.
• Manual: Ran wslc build --iidfile <path> and confirmed the image ID is written to the file; verified an invalid path fails before the build runs and a failed build leaves no file.

[Copilot]

🟡 Not ready to approve

The current iidfile commit path can leave an empty iidfile on successful builds that produce no image ID, and the COM BuildImage ImageId parameter contract is inconsistent (optional vs required) in a way that can trigger RPC null-pointer failures.

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Pull request overview

This PR extends wslc build with Docker parity features by introducing --iidfile <path> (write the resulting image ID to a host file) and wiring up docker-buildx-style --output handling, including client/server plumbing and test coverage.

Changes:

• Add --iidfile support by returning the built image ID from the session BuildImage COM call and committing it to a host file via an RAII helper.
• Add docker-buildx-style --output spec parsing/normalization and streaming of exporter artifacts back to the client when needed.
• Add/extend unit + E2E tests and localization strings for the new CLI surface and validation errors.

File summaries

File	Description
test/windows/WSLCTests.cpp	Updates COM BuildImage calls to pass the new ImageId out-parameter and adjusts invalid-flag testing.
test/windows/wslc/WSLCCLISecretParserUnitTests.cpp	Hardens temp-file creation/writes with explicit failure checks.
test/windows/wslc/WSLCCLIOutputParserUnitTests.cpp	Adds unit tests defining the contract for --output spec parsing/formatting.
test/windows/wslc/e2e/WSLCE2EImageBuildTests.cpp	Adds E2E coverage for --output exporters and --iidfile success/failure behavior.
src/windows/wslcsession/WSLCSession.h	Extends IWSLCSession::BuildImage signature with an ImageId out-parameter.
src/windows/wslcsession/WSLCSession.cpp	Implements returning an image ID via VM --iidfile and streams exporter output back via a handle.
src/windows/wslc/tasks/ImageTasks.cpp	Wires --output and --iidfile into the build task; commits iidfile after build.
src/windows/wslc/services/ImageService.h	Adds BuildOutput model and changes Build() to return image ID; threads output routing inputs.
src/windows/wslc/services/ImageService.cpp	Implements output routing/streaming and extracts the image ID from the session build call.
src/windows/wslc/services/ImageModel.h	Introduces the models::IidFile RAII helper API.
src/windows/wslc/services/ImageModel.cpp	Implements IidFile create/truncate, commit, and delete-on-failure semantics.
src/windows/wslc/commands/ImageBuildCommand.cpp	Registers new --iidfile and --output CLI arguments for the build command.
src/windows/wslc/arguments/SpecParsing.h	Declares ParseOutputSpec/FormatOutputSpec for docker-style --output.
src/windows/wslc/arguments/SpecParsing.cpp	Implements --output spec parsing, validation, and canonical formatting.
src/windows/wslc/arguments/ArgumentDefinitions.h	Adds the iidfile argument definition.
src/windows/service/inc/WSLCShared.idl	Adds build flags for output-directory streaming and returning image ID; updates valid mask.
src/windows/service/inc/wslc.idl	Extends WSLCBuildImageOptions with output fields and adds ImageId out-param to BuildImage.
localization/strings/en-US/Resources.resw	Adds localized strings for --output validation and --iidfile/--output arg descriptions.

Review details

• Files reviewed: 18/18 changed files
• Comments generated: 4
• Review effort level: Low

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[Copilot]

🟢 Ready to approve

The implementation is coherent and well-covered by updated unit/E2E tests, with only minor documentation/comment consistency nits noted.

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Review details

Comments suppressed due to low confidence (2)

test/windows/wslc/WSLCCLIOutputParserUnitTests.cpp:35

• The top-of-file contract comment says non-structural --output attributes are “stored verbatim”, but ParseOutputSpec lowercases attribute keys (and FormatOutputSpec re-serializes the normalized keys). This doc mismatch can mislead future readers/tests about the intended behavior.

      * Otherwise the spec is a comma separated list of key=value pairs. Keys are matched
        case-insensitively. 'type' and 'dest' populate the struct fields; every other key is
        stored verbatim in Attributes (values may themselves contain '=').

src/windows/wslc/services/ImageService.h:45

• BuildOutput’s comment states attributes are “carried verbatim”, but ParseOutputSpec normalizes attribute keys to lowercase (and FormatOutputSpec emits the normalized keys). Updating this comment to reflect the actual behavior will keep API expectations consistent.

// Parsed docker-style --output spec (buildx exporter). Type/Dest are the resolved exporter type and
// destination; any remaining key=value attributes (name, push, compression, ...) are carried verbatim.
struct BuildOutput
{
    std::wstring Type;                               // resolved exporter type (e.g. L"local", L"tar", ...)
    std::wstring Dest;                               // destination path; L"-" means stdout; empty when not applicable
    std::map<std::wstring, std::wstring> Attributes; // remaining key=value attributes
};

• Files reviewed: 18/18 changed files
• Comments generated: 0 new
• Review effort level: Low

We're testing this review assessment. Please use 👍 or 👎 to tell us if it's correct.