Task/10283 load tracks and videos from s3 by selecting a time range

[randy-seng]

What this does

In S3 mode, loading tracks and videos used to have no user-facing entry point — this branch gives it one. The user picks a UTC start/end time range in a new LoadWindowDialog, S3ListObjects lists the bucket under the configured prefix (de-duplicating repeated keys — RustFS, unlike AWS S3, can report the same object
more than once), select_in_window filters to objects whose filename timestamp falls in the range, and DownloadObjects fetches the selected keys concurrently into a local staging directory (user_source) before the existing local-file loading path takes over. For tracks, S3TrackFileProvider additionally reads each
downloaded .ottrk's own metadata to resolve and fetch its companion video — the video is not inferred from the track's filename, since a companion may be any supported video type.

The load is all-or-nothing: a missing video, an unreadable track file, or a user cancel abandons the whole batch rather than leaving a partial load in the repositories. Cancellation is handled by racing a watch_for_cancel task against the download tasks inside one asyncio.TaskGroup, so a cancel reaches downloads already in flight instead of only ones that haven't started yet (previously, checking only between asyncio.gather slots meant a cancel on a multi-gigabyte transfer could go unnoticed for a long time).

Staged downloads are wiped on startup, on shutdown (best-effort), and on project reset — they're explicitly not a cache, since nothing reuses them across runs and the Video objects pointing at them don't survive a restart either.

Why

RunningProgressbar was renamed to CompletionProgress and gained complete(item) and is_cancelled because the existing progressbar interface assumed work advances by iterating a sequence in order. Concurrent downloads complete out of order, so the abstraction had to change to "report each item as it finishes and poll for cancellation" instead.

AskForLoadWindow is a new port in the application layer rather than a method on UiFactory — adding an abstract method there would make OTCloud's UnimplementedUiFactory abstract and break it on instantiation. It also had to live outside plugin_s3 so the front-end implementing it doesn't need to depend on the plugin that consumes it.

LoadWindow is deliberately a separate type from DateRange (which filters tracks already loaded) — this window decides what gets fetched in the first place, and is clamped rather than rejected when a selection exceeds the configured maximum duration (continuous recording produces far more data than can be held at once).

Matching is strict start-in-range: a chunk that started before the window but runs into it is not loaded. This keeps selection predictable at the cost of a leading partial chunk, and is called out explicitly in select_in_window's docstring since it's an easy thing to assume works differently.

MinIO was replaced with RustFS in test fixtures in an earlier commit on this branch (58c1279a) because MinIO stopped publishing free Docker Hub images and later removed the repository entirely, breaking the testcontainers-based acceptance/integration suite.

Notes for the reviewer

Start with OTAnalytics/plugin_s3/download_objects.py — the TaskGroup/cancellation logic is the trickiest part of this change and is exercised directly by tests/unit/OTAnalytics/plugin_s3/test_download_objects.py (test_cancelling_stops_the_downloads_still_in_flight,test_cancelling_mid_download_aborts_it_promptly).

OTAnalytics/plugin_s3/s3_file_providers.py is the other file worth close attention: it's where track/video resolution, error translation (MissingVideoForTrackFile vs UnreadableTrackFile vs a generic bucket/network/filesystem failure), and user-facing messaging all meet. The rest —
filename_timestamp.py, select_objects.py, cleanup.py, the nicegui_application.py wiring — is comparatively mechanical. domain/progress.py's rename (RunningProgressbar → CompletionProgress) touches load_track_files.py and nicegui_gui/nicegui/progressbar.py as call sites; nothing behavioral changed there beyond the new complete/is_cancelled members.

Risk and rollout

Only active when DATA_TRANSFER_MODE=s3 (transfer_mode_from_env()); local mode is untouched. The download concurrency is configurable (S3Config.download_concurrency) — worth confirming the default is sane for the target deployment's bucket and network.

select_in_window's strict start-in-range matching means a recording chunk started just before a window boundary is silently excluded, not partially loaded — expected behavior per the docstring, but worth flagging to whoever signs off on acceptance criteria.

Adds minio and testcontainers as dev dependencies (for spinning up RustFS in tests) and expands pytest testpaths to include tests/integration.

Testing

Acceptance (tests/acceptance/test_load_from_s3.py) and integration (tests/integration/OTAnalytics/plugin_s3/test_load_from_rustfs.py) tests spin up a real RustFS container via testcontainers and exercise the dialog end-to-end against
a live S3 API.

OP#10283