fix: prevent thundering-herd of concurrent Syncthing REST API calls#15
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The background-thread refresh introduced in the previous commit had a new problem: _auto_refresh fires every 3s, but connected_devices() can take up to 30s (3 calls × 10s timeout). Without a guard, 10 overlapping refresh threads accumulate, each making 3 requests = 30 simultaneous requests to Syncthing's REST API, saturating it and making timeouts self-reinforcing. - Add _refreshing flag to _DevicesContent and IncomingWindow: a new fetch is skipped if one is already in flight; flag is cleared in _apply_refresh (or immediately if the window is gone). - Increase auto-refresh interval 3s → 10s in both windows to reduce steady-state API call rate. - Cache get_device_id() in SyncthingClient: the local device ID never changes, but was fetched on every connected_devices() call (every refresh cycle). - Make connected_devices() resilient: if get_connections() times out, return devices with unknown connection status instead of raising. - Downgrade PendingDeviceWatcher timeout logs from exception (full traceback) to warning: a ReadTimeout is routine when Syncthing is busy, not an unexpected crash. https://claude.ai/code/session_0128MyVVEu1Dt3jTeaZ1edyL
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This commit was missed when the previous PRs (#12, #13) were merged.
What this fixes
The background-thread refresh introduced in #13 had a self-reinforcing timeout loop:
_auto_refreshfires every 3 secondsconnected_devices()can take up to 30 seconds (3 calls × 10s timeout each) when Syncthing is slowChanges
clipsync/ui.py_refreshingflag on_DevicesContentandIncomingWindow: skips a new fetch if one is already in flight; flag is cleared in_apply_refreshclipsync/syncthing.pyget_device_id()inSyncthingClient— the local device ID never changes, was being fetched on everyconnected_devices()callconnected_devices()catchesrequests.RequestExceptiononget_connections()and returns the device list with unknown connection status rather than failing entirelyclipsync/pairing.pyReadTimeoutlogs inPendingDeviceWatcherfrom full exception traceback → singleWARNINGlinehttps://claude.ai/code/session_0128MyVVEu1Dt3jTeaZ1edyL
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