# Weatherfeeder Postgres Contract

`weatherapi` reads weather data from Postgres tables owned and populated by
`weatherfeeder`. This document describes only the storage contract consumed by
`weatherapi`; it is not a full weatherfeeder schema reference.

## Version

`go.mod` depends on:

- `gitea.maximumdirect.net/ejr/weatherfeeder v0.11.0`

The repository code also depends on weatherfeeder canonical model types. Table
compatibility must match the SQL in `internal/adapters/outbound/postgres`.

## Boundary

`weatherapi` is read-only:

- it does not create tables;
- it does not migrate tables;
- it does not ingest provider data;
- it does not write weatherfeeder events.

Weatherfeeder owns provider polling, normalization, table shape, and writes.
Postgres owns persistence, backup, restore, and availability.

## Table Families Read

| Resource | Tables read |
| --- | --- |
| Latest observation | `observations`, `observation_present_weather` |
| Current conditions | `observations` |
| Active alerts | `alert_runs`, `alerts`, `alert_references` |
| Hourly forecast | `forecasts`, `forecast_periods` |
| Narrative forecast | `forecasts`, `forecast_periods` |
| Forecast discussion | `forecast_discussions`, `forecast_discussion_key_messages` |
| Weather story run | `weather_story_runs`, `weather_stories` |
| Latest weather story | `weather_stories` |

## Latest Row Selection

Latest parent resources use these ordering rules:

- observations: `observed_at DESC, event_emitted_at DESC`;
- alert runs: `as_of DESC, event_emitted_at DESC`;
- hourly forecasts: `product = 'hourly'`, then `issued_at DESC,
  event_emitted_at DESC`;
- narrative forecasts: `product = 'narrative'`, then `issued_at DESC,
  event_emitted_at DESC`;
- forecast discussions: `issued_at DESC, event_emitted_at DESC`;
- weather story runs: `as_of DESC, event_emitted_at DESC`;
- latest individual weather story: `updated_at DESC, as_of DESC,
  story_order ASC, story_index ASC`.

Current conditions aggregate `observations` rows where `observed_at` is inside
the application-provided observation window.

## Child Ordering

Child rows are loaded separately and attached in stored order:

- observation present weather: `weather_index ASC`;
- alerts: `alert_index ASC`;
- alert references: `alert_index ASC, reference_index ASC`;
- forecast periods: `period_index ASC`;
- forecast discussion key messages: `message_index ASC`;
- weather stories for a run: `story_index ASC`.

## Columns Read

The repository reads only these columns.

### `observations`

`event_id`, `station_id`, `station_name`, `observed_at`, `condition_code`,
`is_day`, `text_description`, `temperature_c`, `dewpoint_c`,
`wind_direction_degrees`, `wind_speed_kmh`, `wind_gust_kmh`,
`barometric_pressure_pa`, `visibility_meters`, `relative_humidity_percent`,
`apparent_temperature_c`, and `event_emitted_at`.

Current conditions additionally aggregate recent `observations` values for
temperature, apparent temperature, dewpoint, humidity, wind speed, wind
direction, condition code, and latest `is_day`.

### `observation_present_weather`

`weather_index`, `raw_text`, and `event_id`.

`raw_text` is decoded as JSON when present. Empty or null raw text maps to an
empty present-weather value; invalid JSON is returned as a repository error.

### `alert_runs`

`event_id`, `location_id`, `location_name`, `as_of`, `latitude`, `longitude`,
and `event_emitted_at`.

### `alerts`

`alert_index`, `alert_id`, `event`, `headline`, `severity`, `urgency`,
`certainty`, `status`, `message_type`, `category`, `response`, `description`,
`instruction`, `sent`, `effective`, `onset`, `expires`, `area_description`,
`sender_name`, and `run_event_id`.

### `alert_references`

`alert_index`, `reference_index`, `id`, `identifier`, `sender`, `sent`, and
`run_event_id`.

### `forecasts`

`event_id`, `location_id`, `location_name`, `issued_at`, `updated_at`,
`product`, `latitude`, `longitude`, `elevation_meters`, and
`event_emitted_at`.

Only `product = 'hourly'` and `product = 'narrative'` are read by implemented
routes.

### `forecast_periods`

`period_index`, `start_time`, `end_time`, `name`, `is_day`,
`condition_code`, `text_description`, `temperature_c`, `temperature_c_min`,
`temperature_c_max`, `dewpoint_c`, `relative_humidity_percent`,
`wind_direction_degrees`, `wind_speed_kmh`, `wind_gust_kmh`,
`barometric_pressure_pa`, `visibility_meters`, `apparent_temperature_c`,
`cloud_cover_percent`, `probability_of_precipitation_percent`,
`precipitation_amount_mm`, `snowfall_depth_mm`, `uv_index`, and
`run_event_id`.

### `forecast_discussions`

`event_id`, `office_id`, `office_name`, `issued_at`, `updated_at`, `product`,
`short_term_qualifier`, `short_term_issued_at`, `short_term_text`,
`long_term_qualifier`, `long_term_issued_at`, `long_term_text`, and
`event_emitted_at`.

### `forecast_discussion_key_messages`

`message_index`, `message_text`, and `run_event_id`.

### `weather_story_runs`

`event_id`, `office_id`, `as_of`, and `event_emitted_at`.

### `weather_stories`

`story_index`, `office_id`, `start_time`, `end_time`, `updated_at`, `title`,
`description`, `alt_text`, `priority`, `story_order`, `download_url`,
`run_event_id`, and `as_of`.

## Nullability and Time Assumptions

The repository scans nullable columns with `sql.Null*` types and maps them to
nil pointers or omitted zero values depending on the canonical model field.

Timestamps returned by the repository are normalized to UTC. Presentation
timezone conversion happens later in HTTP presenters.

Missing latest parent rows return `nil, nil` from repository methods. HTTP
rendering exposes this as a successful response with `data: null`.

## Compatibility Checklist

Before changing weatherfeeder storage or upgrading the weatherfeeder module:

- compare table names and columns with `internal/adapters/outbound/postgres`;
- preserve latest-row ordering columns used by `weatherapi`;
- preserve child index columns used for ordering;
- preserve nullable behavior expected by row mappers;
- run `go test ./internal/adapters/outbound/postgres` and affected HTTP tests.

## Related Docs

- [`docs/internal/postgres-repository.md`](../internal/postgres-repository.md)
- [`docs/operations.md`](../operations.md)
- [`docs/troubleshooting.md`](../troubleshooting.md)