Catapult Trace Viewer

Open Chrome Catapult trace files directly inside VS Code using the legacy Catapult Trace Viewer UI.

This extension is for people who prefer the old chrome://tracing / Catapult timeline experience over newer trace viewers for compatible trace files.

Features

• Open .json, .trace, and .ctrace files with Open With... > Catapult Trace Viewer.
• Use a read-only custom editor so the trace opens inside a normal VS Code editor tab.
• Load the legacy Catapult viewer locally from vendored assets, without sending trace data to a remote web app.
• Preserve the classic light Catapult UI even when VS Code is using a dark theme.

Development

npm install
npm run compile

Then press F5 and open trace.json in the Extension Development Host with Open With... > Catapult Trace Viewer.

You can also right-click a .json, .trace, or .ctrace file and run Open with Catapult Trace Viewer.

To build and install the local VSIX:

npm run package
npm run install

npm run package writes catapult-trace-viewer-vscode-0.0.1.vsix. npm run install rebuilds that VSIX and installs it with code --install-extension --force.

The install helper skips ordinary dependency installs, so npm install will not reinstall the extension.

To publish to the VS Code Marketplace after logging in with vsce login peiqingj:

npm run publish:marketplace

Release

The repository has two GitHub workflows:

• CI builds and packages the extension on pushes and pull requests.
• Release VSIX creates a GitHub release and uploads the packaged .vsix when a v* tag is pushed, or when run manually from the Actions tab.

For a local release package only:

npm run package

Notes

This extension vendors the legacy Catapult viewer assets used by Chrome's old tracing UI. The viewer depends on deprecated WebComponents V0 behavior and a polyfill, so some edge cases may behave differently from old Chrome builds.

Current limitations:

• Large traces may consume a lot of webview renderer memory.
• The CSP is intentionally relaxed for the legacy Catapult bundle.

Third Party Notices

See vendor/THIRD_PARTY_NOTICES.md for Catapult and WebComponents licensing notes.