Operator-flagged 2026-06-01: downloaded images stayed at
thumbnail_path=NULL until a periodic backfill sweep picked them up,
surfacing as broken-thumbnail tiles in the gallery for hours after
the download landed.
Importer.attach_in_place deliberately skips inline thumbnail
generation (importer.py:591-592) so the import queue stays moving —
the CALLING task is responsible for the enqueue. tasks/import_file.py
already did this (line 228-239). tasks/download.py / download_service
did not — every gallery-dl-attached image landed un-thumbnailed.
Fix in download_service._phase3_persist: after each
`attach_in_place` returning status in (imported, superseded), fan out
`generate_thumbnail.delay()` + `tag_and_embed.delay()` for each
image_id. Lazy import avoids circular-import risk between
download_service and the celery task modules that depend on it.
Mirrors the existing pattern verbatim — single source of truth for
"what fires after a successful attach" remains a comment in two
places (filesystem-import task, download orchestrator) rather than
a shared helper, because the contexts differ enough (sync session vs
async orchestrator) that abstracting would obscure more than it'd
share.
Test covers the happy-path with two attached files: both get the
thumbnail enqueue AND the ML enqueue, with image_ids drawn from
ImportResult (so future supersede-on-attach paths stay covered).
Routine subscription polls walked the entire post history every tick
even when nothing had changed, because gallery-dl's default `skip: True`
continues iterating archived posts. A creator with ~550 archived posts
(Knuxy patreon) saturates the 870s wall-clock cap before completing,
even with zero downloads needed. Plus, a tier-limited run that
downloaded hundreds of files but ran out the clock should be a
warning, not an error.
Two coupled changes, both operator-flagged 2026-06-01:
* **Tick mode (default, cron polls).** New `TICK_SKIP_VALUE = "exit:20"`
asks gallery-dl to exit after 20 contiguous archived items. Fresh
subscriptions + new-content cases still walk normally; established
subscription with zero new content exits in ~30s of HEAD requests
instead of pegging the timeout. 20 (not 5) gives headroom against
paywall warnings interleaving with archived items.
* **Backfill mode (explicit, operator-triggered).** Sticky for N runs
via new `Source.backfill_runs_remaining` (alembic 0031). While > 0,
downloads use `skip: True` + 1800s timeout. Auto-decrements per run
with early-reset to 0 when a clean run finds zero files (queue
drained). N defaults to 3 — multiple runs give the system enough
budget to finish a deep walk across timeout boundaries. New
`POST /api/sources/{id}/backfill` arms the source; "Deep scan"
button on each SourceRow (chip shows remaining count) wires it.
Plus partial-success classifier: non-zero gallery-dl exit + ≥1 file
downloaded + no source-level error fires `ErrorType.PARTIAL`, which
download_service maps to `status=\"ok\"`. The run did real work; the
next tick continues via gallery-dl's archive. No more red events for
"timed out mid-walk after downloading 300 files."
Retires `SourceConfig.skip_existing` — skip value is now derived from
the source state and passed as a separate `skip_value` parameter
through download() / _build_config_for_source(). `GD_DEFAULTS` drops
the now-dead key (was inert data after this refactor).
Tests cover:
* tick + backfill skip-value emission in _build_config_for_source
* PARTIAL classifier branch + TIER_LIMITED-wins-over-PARTIAL ordering
* SourceService.set_backfill_runs validation + persistence
* /api/sources/{id}/backfill 200/400/404 paths
* download_service auto-decrement / auto-reset / tick-mode-no-touch
* PARTIAL → status=ok in the orchestrator (no consecutive_failures bump)
bvandeusen