http://go/aboutsync

Overview

• Located in about:sync (or chrome://sync-internals)
• Inspired by chrome://net-internals
• Tabs:
• About tab: "Classic" about:sync page, concise status overview
• Data tab: dump debugging data to text for copy & paste
• Notifications tab: Keeps track of incoming sync notifications
• Events tab: logs for sync-related events
• Sync Node Browser tab: browse all synced data

About tab

• "Classic" about:sync page
• Updates on the fly
• Try moving a bookmark, or stopping and starting sync
• Some stuff will eventually be moved out, but page is still useful as an overview

Data tab

• Dump to text button
• Dumps all info from about, notifications, and events tab
• Once M11 goes stable, can tell users to:
• Open about:sync
• Repro the problem if possible
• Wait a while (15-30 seconds)
• Go to data tab
• Dump info, paste into bug (or email privately if there's sensitive info)
• Event log will probably be most useful part
• Room for improvement
• Redact sensitive info
• Automatically highlight dumped text, add "Copy to clipboard" button
• Button to add to an existing bug, or create a new one

Notifications tab

• If a notification is received when the page (not just the tab) is open, a counter will increment (one for each data type)
• Try moving a bookmark, setting a preference, or stopping and starting sync
• Takes ~5-10 seconds for a notification to bounce back
• Counters reset if you reload
• Room for improvement
• More detailed connection stats
• How long has connection been up?  Which XMPP server/port?  How long ago was the last message sent/received?

Events tab

• Shows all sync events (i.e., functions in SyncManager::Observer and incoming notifications) that happen as long as the page is open
• Try moving a bookmark, or starting sync (dumps lots of data!)
• Doesn't quite log everything yet
• Only logs events after backend is initialized
• Resets if you reload
• Room for improvement
• Store last N events (C++ side) so you can open it right when you hit a problem and still get some useful info
• Also log requests/responses to HTTP server
• Perhaps more logging for sync setup events
• Better display (82866)
• Start logging even before backend is initialized (tricky)

Sync node browser tab

• Shows sync nodes
• One at a time if M11, tree view if canary/ToT
• M11 version
• Sync nodes are structured in a tree.
• Each data type has a top-level node which is a child of the root node
• Bookmark top-level node is named "Google Chrome" for historical reasons
• Only bookmarks sub-tree has true tree structure
• Everything else is just a list under the top-level node
• Use links to navigate tree: parent, first child, predecessor, successor
• Ignore specifics information for folder
• Tree view version
• Tree visualized on the left, details of selected node on the right
• Does not auto-update; you need to refresh
• Be careful, you may lose logged events; you can always open a new about:sync tab instead
• Room for improvement
• CSS/JS tweaks to make tree view nicer
• Overflow behavior, scrolling behavior
• Implement auto-updating (hard)
• Add a refresh button (easier)
• Search (id/client tag/full-text)
• Cut down on the large number of displayed empty fields (empty strings, etc.) (see autofill nodes)

Network-level debugging

Room for improvement

• Data type-specific tabs
• Model associators / change processors have access to the ProfileSyncService, so shouldn't be too hard to emit events or reply to calls
• Probably easier for things that live on the UI thread
• Some way to capture VLOG() events
• Should be obvious when sync isn't working
• Use HTML notifications for events
• Front-end for memory usage info (Lingesh is working on backend)