Persist port mapping and volume information for containers across WSLA sessions by kvega005 · Pull Request #14118 · microsoft/WSL

kvega005 · 2026-01-28T00:44:10Z

Summary of the Pull Request

Added support to persist WSLA container metadata (port mappings, volume mounts, TTY setting) in a Docker label. This enables running containers with their full configuration when opening them from previous sessions.

Changes

New Container Metadata Schema (docker_schema.h)

Added WSLAContainerMetadataLabel constant for the label key
Added ContainerMetadata struct with JSON schema for storing:
- Volume mounts (host path, VM path, container path, read-only flag)
- Port mappings (host port, VM port, container port, family, mapped-to-host flag)
- TTY setting

Container Creation (WSLAContainer.cpp)

On Create(), serialize metadata to JSON and store in Docker label

Container Recovery (WSLAContainer.cpp)

On Open(), read metadata from Docker label
Re-mount volumes and re-map ports using stored configuration

Tests (WSLATests.cpp)

Added ContainerVolumeAndPortRecoveryFromStorage test that:
- Creates a container with volumes and ports
- Recovers it in a new session and verifies port/volume work
- Verifies session creation succeeds when host folder for volume is missing

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 adds support for persisting WSLA container metadata (volumes, port mappings, and TTY settings) in Docker container labels, enabling containers to be recovered with full configuration across WSLA session restarts.

Changes:

Introduced a JSON-based metadata schema stored in Docker labels to persist container configuration (volumes, ports, TTY)
Changed WSLA_VOLUME.HostPath API from LPCWSTR to LPCSTR for consistency with other string fields
Refactored port mapping logic to support both creation-time and recovery-time scenarios

Reviewed changes

Copilot reviewed 8 out of 8 changed files in this pull request and generated 9 comments.

Show a summary per file

File	Description
src/windows/wslaservice/exe/WSLAContainerMetadata.h	New metadata schema with JSON serialization for volumes, ports, and TTY settings
src/windows/wslaservice/exe/WSLAContainer.h	Updated type signatures to use WSLAVolumeMount and WSLAPortMapping from metadata schema
src/windows/wslaservice/exe/WSLAContainer.cpp	Implemented metadata serialization on Create(), deserialization on Open(), and refactored port/volume handling
src/windows/inc/docker_schema.h	Added Labels field to CreateContainer request for metadata storage
src/windows/wslaservice/inc/wslaservice.idl	Breaking API change: WSLA_VOLUME.HostPath changed from LPCWSTR to LPCSTR
src/windows/common/WSLAContainerLauncher.h	Updated AddVolume and Create method signatures to use std::string instead of std::wstring
src/windows/common/WSLAContainerLauncher.cpp	Updated implementation to handle string-based paths and added Create method
test/windows/WSLATests.cpp	Added comprehensive recovery test and updated existing tests for string-based path API

OneBlue

Change looks good, added a couple minor comments

Copilot

Pull request overview

Copilot reviewed 7 out of 7 changed files in this pull request and generated 4 comments.

Copilot

Pull request overview

Copilot reviewed 7 out of 7 changed files in this pull request and generated 3 comments.

Copilot · 2026-01-30T00:04:52Z

+        // Delete the host folder to simulate volume folder being missing on recovery
+        cleanup.reset();
+
+        // Create a new session - this should succeed even though the volume folder is gone


The comment is slightly misleading. The session creation succeeds not because "the volume folder is gone" but because the container was already deleted in the previous session (line 2544). When OpenContainer is called, it returns ERROR_NOT_FOUND because the Docker container no longer exists, not because of the missing volume folder. Consider updating the comment to clarify that the container was deleted before the session was created.

Suggested change

// Delete the host folder to simulate volume folder being missing on recovery

cleanup.reset();

// Create a new session - this should succeed even though the volume folder is gone

// Delete the host folder to simulate the volume folder being missing before recovery.

cleanup.reset();

// Create a new session. This succeeds because the container was deleted in the previous

// session; OpenContainer below is expected to return ERROR_NOT_FOUND for the missing

// container, regardless of the missing volume folder.

Copilot

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Copilot

Pull request overview

Copilot reviewed 7 out of 7 changed files in this pull request and generated 6 comments.

benhillis

I think some of these copilot comments are legit.

…kvega005/WSL into user/kevinve/container-metadata

ptrivedi · 2026-02-02T17:17:28Z

+    case ContainerState::Running:
+    case ContainerState::Restarting:
+        return WSLA_CONTAINER_STATE::WslaContainerStateRunning;
+    case ContainerState::Paused:


Should Paused state be clubbed with Created instead of Exited? I believe on both those types of states one could all container Start and be able to get a running container.

We do not really support pausing containers today and have not looked into what we need to resume a paused container, so I figured it's probably not worth handling in this PR.

Maybe leave a TODO here to revisit. I think a container in 'Restarting' state should also likely not be considered 'Running'. Though not sure what could cause those containers to go into these states if we don't support these operations (e.g. a container with a suspended process would be in Paused state)... in which case, maybe those should be considered invalid states?

Thats a good point, we can consider them invalid states for now.

Outdated

kvega005 added 4 commits January 27, 2026 14:05

Persist container metadata across WSLA sessions

b1e3890

Fix network and ports

e60b46a

Add test

f1c2e9b

Verify conainer recovery doesnt break starting WSLA Session

220e2c5

kvega005 requested a review from a team as a code owner January 28, 2026 00:44

Copilot AI review requested due to automatic review settings January 28, 2026 00:44

Copilot started reviewing on behalf of kvega005 January 28, 2026 00:44 View session

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OneBlue reviewed Jan 28, 2026

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Comment thread src/windows/wslaservice/exe/WSLAContainerMetadata.h Outdated

Comment thread test/windows/WSLATests.cpp Outdated

Comment thread test/windows/WSLATests.cpp

Comment thread src/windows/wslaservice/inc/wslaservice.idl Outdated

Address suggestions

77fd43a

OneBlue reviewed Jan 28, 2026

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Comment thread src/windows/wslaservice/exe/WSLAContainer.cpp Outdated

OneBlue reviewed Jan 28, 2026

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Comment thread src/windows/wslaservice/exe/WSLAContainer.cpp Outdated

kvega005 added 3 commits January 28, 2026 14:24

Fix versioning

f74e6ed

Add invalid metadata test

397d9fc

Fix formatting

61d9949

OneBlue approved these changes Jan 29, 2026

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benhillis requested a review from Copilot January 29, 2026 17:10

Copilot started reviewing on behalf of benhillis January 29, 2026 17:11 View session

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Comment thread test/windows/WSLATests.cpp Outdated

Comment thread test/windows/WSLATests.cpp

Comment thread test/windows/WSLATests.cpp Outdated

kvega005 added 2 commits January 29, 2026 11:33

fix typos

9c468c5

Merge branch 'feature/wsl-for-apps' into user/kevinve/container-metadata

0c6d414

kvega005 requested a review from Copilot January 29, 2026 23:59

Copilot started reviewing on behalf of kvega005 January 29, 2026 23:59 View session

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benhillis requested a review from Copilot January 30, 2026 00:40

Copilot started reviewing on behalf of benhillis January 30, 2026 00:40 View session

Copilot AI reviewed Jan 30, 2026

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Merge branch 'feature/wsl-for-apps' into user/kevinve/container-metadata

bdc7d9d

benhillis previously requested changes Jan 30, 2026

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kvega005 added 2 commits January 30, 2026 10:42

Address suggestions

1a9819f

Merge branch 'user/kevinve/container-metadata' of https://github.com/…

64035bc

…kvega005/WSL into user/kevinve/container-metadata

kvega005 requested a review from benhillis January 30, 2026 18:46

OneBlue reviewed Jan 31, 2026

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Comment thread src/windows/wslaservice/exe/WSLAContainer.cpp

OneBlue approved these changes Jan 31, 2026

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ptrivedi reviewed Feb 2, 2026

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Comment thread src/windows/wslaservice/exe/WSLAContainer.cpp Outdated

ptrivedi reviewed Feb 2, 2026

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OneBlue approved these changes Feb 2, 2026

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kvega005 and others added 5 commits February 2, 2026 11:34

improve port allocation comments

a946c77

Address suggestions about container state

378c681

Add to do for container states

3d2f5a1

Merge branch 'feature/wsl-for-apps' into user/kevinve/container-metadata

cf240ef

Fix bad merge

0c59f53

kvega005 and others added 4 commits February 3, 2026 12:23

Fix formatting

11eb169

Fix bad merge

1480796

Merge branch 'feature/wsl-for-apps' into user/kevinve/container-metadata

385d0b9

Fix broken test

2f7422b

kvega005 merged commit f4de0e4 into microsoft:feature/wsl-for-apps Feb 5, 2026
6 checks passed

kvega005 deleted the user/kevinve/container-metadata branch February 5, 2026 00:17

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kvega005 commented Jan 28, 2026

Summary of the Pull Request

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