Add session status display to System Status tab and fix stale-session detection#685
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SimonHeybrock wants to merge 7 commits intomulti-sessionfrom
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Add session status display to System Status tab and fix stale-session detection#685SimonHeybrock wants to merge 7 commits intomulti-sessionfrom
SimonHeybrock wants to merge 7 commits intomulti-sessionfrom
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Rename "Backend Status" tab to "System Status" and add a new section showing active dashboard sessions. The current session is highlighted with a "You" badge and sorted first. Changes: - Add subscriber mechanism to SessionRegistry (mirrors ServiceRegistry) - Create SessionStatusWidget showing active sessions with heartbeat info - Create SystemStatusWidget combining session and backend status - Update PlotGridTabs and ReductionApp to use new combined widget Prompt: This branch adds multi-session support (see SessionRegistry). I would be useful if the UI had info about the active (or stale) sessions. Please investigate how we could do this. I am thinking we could use the "Backend Status" tab - rename it an move backend status to a section, adding a new section with session info. Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
When a browser tab is refreshed, Panel's on_session_destroyed callback may not fire reliably. This leaves the old session showing as "Active" until the 60-second cleanup timeout. Fix by: - Adding "Stale" status (red badge) for sessions without heartbeats for >5 seconds, providing immediate visual feedback - Adding periodic refresh of session status display via SessionUpdater to keep heartbeat times and stale indicators current - Including stale count in the summary line Prompt: I see a problem: This status page now indicates that when refreshing the page it leads to sessions that are still marked as "active". Is the browser not ending the session properly? Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
The previous approach used a Button with jscallback triggered by an HTML script that searched for the button by text content. This was fragile: - Panel 1.x Shadow DOM makes document.querySelectorAll unreliable - Hidden buttons (visible=False) may not render properly - Finding buttons by textContent is brittle Replace with ReactiveHTML's _scripts['render'] pattern, which runs JavaScript automatically when the component loads. The HeartbeatWidget increments a counter every 5 seconds; Panel's bidirectional sync updates the Python parameter, allowing detection of browser disconnection. Key implementation notes from Panel issue #4925: - Use += 1, not ++ (increment operators break param sync) - Include 'remove' script to clearInterval and prevent memory leaks Also adjust stale threshold from 5s to 15s to allow for network delay (heartbeats arrive every 5s, so 15s = 3 missed heartbeats). Prompt: Need your help finding out how to properly identify stale session with panel. See recent commit and uncommitted changes for failed attempts. Do some research and think. Let us not just try random things. Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
The widget was subscribing to session registry notifications via register_update_subscriber(), but these notifications can come from a background thread (cleanup_stale_sessions in the update loop). Calling refresh() from a background thread causes pn.io.hold() to not batch updates properly, leading to flicker. The periodic refresh via SessionUpdater.register_custom_handler() already updates the display every 500ms within the correct Panel session context. Remove the redundant subscription and rely solely on polling. Prompt: The "Dashboard Sessions" widget (or the entire System Status tab?) seem to not sync updates of individual subwidgets (like time info). Are we missing a pn.io.hold()? Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
The widget was refreshing every 500ms (the SessionUpdater polling rate), but the heartbeat time display only needs to update every few seconds. Add a 2-second minimum interval between refreshes to reduce unnecessary UI updates. Prompt: The update every 500ms is too "busy". While we need this frequency in other parts, here we do not want it. Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
SimonHeybrock
changed the title
The register_update_subscriber mechanism was removed from SessionStatusWidget in favor of polling. Remove the now-unused subscriber infrastructure from SessionRegistry: - register_update_subscriber method - _notify_update method - _update_subscribers list - Related tests Prompt: Is register_update_subscriber in SessionRegistry unused? Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
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Summary
Example
Key changes
New widgets:
HeartbeatWidget: ReactiveHTML component that sends periodic heartbeats from browser to server via bidirectional param syncSessionStatusWidget: Displays list of active sessions with status badges and heartbeat timesSystemStatusWidget: Combines session status and backend worker status into unified System Status tabSession tracking improvements:
SessionRegistrygainsget_seconds_since_heartbeat()and update subscriber supportSessionUpdateruses HeartbeatWidget instead of fragile button-click approach for browser liveness detectionTest plan
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