Adds an optional async hook on SourceAdapter so any adapter can surface a
settings-driven preview on its /adapters/<name> edit page. The framework
renders the result generically as a table — no adapter-name branches in
GUI templates or route code.
Framework changes:
- src/central/adapter.py: new async preview_for_settings(self, settings)
on the base class, default returns None. Adapters opt in by overriding;
non-overriding adapters render unchanged.
- src/central/gui/routes.py: GET /adapters/{name} instantiates the adapter
with a no-op _PreviewConfigStore stub and a /dev/null cursor path (GUI
has no live ConfigStore), constructs settings_obj via the schema, and
calls preview_for_settings inside a try/except. Result lands in template
context as preview_rows / preview_error.
- src/central/gui/templates/_adapter_preview.html: new partial. Generic
table with columns derived from the first dict's keys; error banner
mirrors the existing last_error article style.
- src/central/gui/templates/adapters_edit.html: one-line include between
the Region fieldset and Save/Cancel.
NWIS opt-in:
- New NWIS_MONITORING_LOCATIONS_URL constant and _PREVIEW_LIMIT cap of 50.
- preview_for_settings returns None when region is None, otherwise one-shot
fetches monitoring-locations within the bbox via a fresh aiohttp session.
Must work even when adapter is not started -- the GUI process never calls
startup(). Returns list[dict] with the contract column order: site_id,
name, site_type, state. Errors propagate so the framework can render the
operator-visible banner.
- HTTP call factored into _fetch_preview_text so tests mock cleanly.
Tests (7 new):
- tests/test_preview_hook.py: default returns None; partial renders list
with correct headers/rows/count; partial renders error banner; partial
renders empty when both context values are None.
- tests/test_nwis.py adds TestNWISPreview: returns None without region,
returns rows with correct column order, propagates HTTP errors.
Verification:
- 457/457 full suite green (was 450; +7 new tests).
- Live /adapters/nwis preview returns 50 rows with the contract keys
against the current production Iowa bbox.
- /adapters/eonet preview_for_settings returns None via base default --
proves framework is duck-typed, no NWIS-specific code in framework.
NASA WaterData OGC API v0 (latest-continuous collection) — polls configured
parameter codes within an operator-set bbox and publishes on the new
CENTRAL_HYDRO stream.
- Subject: central.hydro.<parameter_code>.<agency>.<bare_site_no>
(e.g. central.hydro.00060.usgs.05420500). The agency/site decomposition
lives in a single _subject_tokens_for_id helper.
- Default parameter codes: 00060 (discharge), 00065 (gage height),
00010 (water temperature). Operator-tunable; single SoT in
_DEFAULT_PARAMETER_CODES — no parallel literals.
- Composite dedup: nwis:<monitoring_location_id>:<param>:<time_iso>.
Prefix kept in dedup key for cross-agency uniqueness.
- Pagination: follows OGC 'rel=next' link until absent (cursor-based).
- Region bbox is REQUIRED in practice; adapter logs WARN at startup if
region is None (does not refuse to start).
- New stream CENTRAL_HYDRO added to streams.py registry (one line).
Retention mirrors CENTRAL_DISASTER (7 days, 1 GiB).
- No removal pattern in v1 — sites are static; missing data is the signal.
Upstream divergences from the original spec brief, caught by pre-build curl:
- Collection is 'latest-continuous', not 'instantaneous-values'.
- Site filter param is 'monitoring_location_id' (singular), not
'monitoring_locations_id' (plural).
- Site identifier requires agency prefix in queries (USGS-NNNNN).
- feature.id is a per-record UUID, not stable; dedup uses joint key.
Ships disabled; operator enables via GUI after setting a bbox.
