The progress-milestone and HMS-error notification paths in
on_printer_status_change held a session across the ~15s camera snapshot
taken for the notification image, pinning a pooled connection per
milestone/error per printer.
The snapshot needs no DB: read the printer in a short session, release
it, grab the snapshot with none held, then open a fresh session for the
notification send (and lift the db-free MQTT publish out too). Pinned by
a test that fails if the snapshot runs while a session is open.
Two tightly-coupled deliverables in one drop -- a new AMS Filament Backup
status/control surface, and the #1766 fix that depends on it.
Added -- AMS Filament Backup status + control
- Parse bit 18 of top-level print.cfg into PrinterState.ams_filament_backup
on every push_status. Verified against OrcaSlicer source
(DeviceManager.cpp:4961) and a live H2D ON/OFF capture. Tri-state
(None = A1 family / pre-cfg push) preserves today's behaviour.
- Hold-timer guard (3 s) prevents stale frames from flickering the badge
back to the printer's old cfg after a user-initiated toggle.
- POST /printers/{id}/ams-backup toggle, set_ams_filament_backup() client
method calling _set_print_option("auto_switch_filament", enabled).
- GET /printers/{id}/inventory-remain endpoint exposes the same map the
dispatcher uses (internal and Spoolman modes both work uniformly).
- Small icon badge in the printer card's "Filaments" section header
(placement reads as printer-wide because the cfg bit is printer-wide,
not per-AMS). Click to toggle, success toast.
- 5 i18n keys x 11 locales for the badge UI.
Fixed -- #1766: prefer_lowest didn't pick lowest, ignored backup state
- Backend gate in _compute_ams_mapping_for_printer: coerce prefer_lowest
to False when status.ams_filament_backup is False; log the skip.
- New effectivePreferLowest(setting, backup) helper applied at every
frontend sort entry point: single-printer PrintModal, multi-printer
hook per-printer, PrinterSelector InlineMappingEditor, FilamentMapping
standalone editor (the last had NO preferLowest awareness at all
before this change).
- New preferLowestSortKey(f, inventoryByTrayId) mirrors backend's two-tier
key exactly, including the banding tie-break (regular AMS < AMS-HT <
external) so the client-side pre-compute matches the dispatch-time pick.
An earlier draft used a flat `amsId * 4 + trayId` priority which gave
external slots (ams_id = -1) a NEGATIVE priority -- caught in code
review before commit.
- Settings -> Filament -> "Prefer lowest remaining filament" gets an
explanatory note about the printer-side AMS Backup dependency, with
i18n key in all 11 locales.
The provider toggle, schema, template, and NotificationService.on_printer_offline
all shipped, but no caller invoked the dispatcher — the offline event was an
orphan toggle. Edge detection in on_printer_status_change now schedules a
debounced (60s) background task on the connected→disconnected transition;
reconnect before the window elapses cancels it. Covers both upstream paths
(smart-plug power-off via mark_printer_offline, and MQTT staleness via
check_staleness), both of which already route through the status callback.
The "back online" channel is the existing print-failure notification on
firmware FAILED report — no symmetric on_printer_online needed.
maziggy