Fix memory leaks in process management #224

ghostwriternr · 2025-11-17T14:56:10Z

Fixes memory leaks from three sources: listener accumulation during log streaming, unbounded process storage, and stale Durable Object state after container restarts.

Changes:

ProcessStore persists completed processes to disk and frees memory
ReadableStream cancel handlers remove listeners when streaming stops
Sandbox onStop lifecycle hook clears container-specific state

Memory leaks occurred from three sources: event listeners accumulated when log streaming was cancelled, completed processes remained in memory indefinitely, and Durable Object state retained invalid references after container restarts. The ProcessStore now persists completed processes to disk while keeping active processes in memory. ReadableStream cancel handlers properly remove listeners when log streaming stops. The Sandbox onStop lifecycle hook clears container-specific state to prevent stale references.

changeset-bot · 2025-11-17T14:56:13Z

🦋 Changeset detected

Latest commit: 455ed50

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

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@cloudflare/sandbox	Patch

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The onStop lifecycle hook now properly awaits storage deletions to ensure cleanup completes before shutdown. Processes are deleted from memory before persisting to disk to prevent race conditions during concurrent access. Stream listeners are cleaned up on all close paths, not just cancellation. The list method now scans disk to include completed processes, maintaining backward compatibility.

pkg-pr-new · 2025-11-17T16:26:07Z

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npm i https://pkg.pr.new/cloudflare/sandbox-sdk/@cloudflare/sandbox@224

commit: 55421ae

github-actions · 2025-11-17T16:26:08Z

🐳 Docker Image Published

FROM cloudflare/sandbox:0.0.0-pr-224-094eefd

Version: 0.0.0-pr-224-094eefd

You can use this Docker image with the preview package from this PR.

Write to disk before deleting from memory to prevent data loss if write fails. Always delete from memory regardless of write success to prevent memory leaks.

Bun.file().exists() returns false for directories, causing list() to skip disk scanning and miss completed processes. Remove the directory existence check and rely on error handling instead.

Test coverage for memory/disk hybrid storage, terminal state transitions, disk persistence, write failure handling, and list() filtering.

Verify completed processes can be retrieved via get() with exit codes and timestamps, and that list() includes both running and completed processes.

Change from /tmp/.sandbox-internal to /tmp/sandbox-internal for better debuggability. Makes it easier to discover and inspect process files during development and troubleshooting.

Event handler called store.update() fire-and-forget, causing API queries to return stale data before disk writes completed. Changed SessionManager to accept async callbacks and await them, ensuring store updates complete before processing next event. This provides strong consistency while maintaining the memory leak fix that moves completed processes to disk.

Applies memory leak prevention from this PR to the activeMounts feature that was merged from main. When a container stops or restarts, mount points become invalid but the Map still held stale references. Clearing it maintains consistency with portTokens and defaultSession.

ghostwriternr added 2 commits November 17, 2025 14:24

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