Updates to the nws forecast source and normalizer to separate code specific to hourly forecasts and prepare for upcoming feature addition of daily and narrative forecasts

internal/sources/nws/forecast_hourly.go

@@ -0,0 +1,129 @@
+// FILE: internal/sources/nws/forecast_hourly.go
+package nws
+
+import (
+	"context"
+	"encoding/json"
+	"strings"
+	"time"
+
+	"gitea.maximumdirect.net/ejr/feedkit/config"
+	"gitea.maximumdirect.net/ejr/feedkit/event"
+	nwscommon "gitea.maximumdirect.net/ejr/weatherfeeder/internal/providers/nws"
+	"gitea.maximumdirect.net/ejr/weatherfeeder/internal/sources/common"
+	"gitea.maximumdirect.net/ejr/weatherfeeder/standards"
+)
+
+// HourlyForecastSource polls an NWS hourly forecast endpoint and emits a RAW forecast Event.
+//
+// It intentionally emits the *entire* upstream payload as json.RawMessage and only decodes
+// minimal metadata for Event.EffectiveAt and Event.ID.
+//
+// Output schema (current implementation):
+//   - standards.SchemaRawNWSHourlyForecastV1
+type HourlyForecastSource struct {
+	http *common.HTTPSource
+}
+
+func NewHourlyForecastSource(cfg config.SourceConfig) (*HourlyForecastSource, error) {
+	const driver = "nws_forecast_hourly"
+
+	// NWS forecast endpoints are GeoJSON (and sometimes also advertise json-ld/json).
+	hs, err := common.NewHTTPSource(driver, cfg, "application/geo+json, application/json")
+	if err != nil {
+		return nil, err
+	}
+
+	return &HourlyForecastSource{http: hs}, nil
+}
+
+func (s *HourlyForecastSource) Name() string { return s.http.Name }
+
+// Kind is used for routing/policy.
+func (s *HourlyForecastSource) Kind() event.Kind { return event.Kind("forecast") }
+
+func (s *HourlyForecastSource) Poll(ctx context.Context) ([]event.Event, error) {
+	raw, meta, err := s.fetchRaw(ctx)
+	if err != nil {
+		return nil, err
+	}
+
+	// EffectiveAt is optional; for forecasts it’s most naturally the run “issued” time.
+	// NWS gridpoint forecasts expose generatedAt (preferred) and updateTime/updated.
+	var effectiveAt *time.Time
+	switch {
+	case !meta.ParsedGeneratedAt.IsZero():
+		t := meta.ParsedGeneratedAt.UTC()
+		effectiveAt = &t
+	case !meta.ParsedUpdateTime.IsZero():
+		t := meta.ParsedUpdateTime.UTC()
+		effectiveAt = &t
+	}
+
+	emittedAt := time.Now().UTC()
+
+	// NWS gridpoint forecast GeoJSON commonly has a stable "id" equal to the endpoint URL.
+	// That is *not* unique per issued run, so we intentionally do not use it for Event.ID.
+	// Instead we rely on Source:EffectiveAt (or Source:EmittedAt fallback).
+	eventID := common.ChooseEventID("", s.http.Name, effectiveAt, emittedAt)
+
+	return common.SingleRawEvent(
+		s.Kind(),
+		s.http.Name,
+		standards.SchemaRawNWSHourlyForecastV1,
+		eventID,
+		emittedAt,
+		effectiveAt,
+		raw,
+	)
+}
+
+// ---- RAW fetch + minimal metadata decode ----
+
+type hourlyForecastMeta struct {
+	// Present for GeoJSON Feature responses, but often stable (endpoint URL).
+	ID string `json:"id"`
+
+	Properties struct {
+		GeneratedAt string `json:"generatedAt"` // preferred “issued/run generated” time
+		UpdateTime  string `json:"updateTime"`  // last update time of underlying data
+		Updated     string `json:"updated"`     // deprecated alias for updateTime
+	} `json:"properties"`
+
+	ParsedGeneratedAt time.Time `json:"-"`
+	ParsedUpdateTime  time.Time `json:"-"`
+}
+
+func (s *HourlyForecastSource) fetchRaw(ctx context.Context) (json.RawMessage, hourlyForecastMeta, error) {
+	raw, err := s.http.FetchJSON(ctx)
+	if err != nil {
+		return nil, hourlyForecastMeta{}, err
+	}
+
+	var meta hourlyForecastMeta
+	if err := json.Unmarshal(raw, &meta); err != nil {
+		// If metadata decode fails, still return raw; Poll will fall back to Source:EmittedAt.
+		return raw, hourlyForecastMeta{}, nil
+	}
+
+	// generatedAt (preferred)
+	genStr := strings.TrimSpace(meta.Properties.GeneratedAt)
+	if genStr != "" {
+		if t, err := nwscommon.ParseTime(genStr); err == nil {
+			meta.ParsedGeneratedAt = t.UTC()
+		}
+	}
+
+	// updateTime, with fallback to deprecated "updated"
+	updStr := strings.TrimSpace(meta.Properties.UpdateTime)
+	if updStr == "" {
+		updStr = strings.TrimSpace(meta.Properties.Updated)
+	}
+	if updStr != "" {
+		if t, err := nwscommon.ParseTime(updStr); err == nil {
+			meta.ParsedUpdateTime = t.UTC()
+		}
+	}
+
+	return raw, meta, nil
+}