Moved broadly useful helper functions upstream into feedkit

sources/helpers.go

@@ -0,0 +1,145 @@
+package sources
+
+import (
+	"fmt"
+	"sort"
+	"strings"
+	"time"
+
+	"gitea.maximumdirect.net/ejr/feedkit/config"
+	"gitea.maximumdirect.net/ejr/feedkit/event"
+)
+
+// DefaultEventID applies feedkit's default Event.ID policy:
+//
+//   - If upstream provides an ID, use it (trimmed).
+//   - Otherwise, ID is "<Source>:<EffectiveAt>" when available.
+//   - If EffectiveAt is unavailable, fall back to "<Source>:<EmittedAt>".
+//
+// Timestamps are encoded as RFC3339Nano in UTC.
+func DefaultEventID(upstreamID, sourceName string, effectiveAt *time.Time, emittedAt time.Time) string {
+	if id := strings.TrimSpace(upstreamID); id != "" {
+		return id
+	}
+
+	src := strings.TrimSpace(sourceName)
+	if src == "" {
+		src = "UNKNOWN_SOURCE"
+	}
+
+	if effectiveAt != nil && !effectiveAt.IsZero() {
+		return fmt.Sprintf("%s:%s", src, effectiveAt.UTC().Format(time.RFC3339Nano))
+	}
+
+	t := emittedAt.UTC()
+	if t.IsZero() {
+		t = time.Now().UTC()
+	}
+
+	return fmt.Sprintf("%s:%s", src, t.Format(time.RFC3339Nano))
+}
+
+// SingleEvent constructs, validates, and returns a slice containing exactly one event.
+func SingleEvent(
+	kind event.Kind,
+	sourceName string,
+	schema string,
+	id string,
+	emittedAt time.Time,
+	effectiveAt *time.Time,
+	payload any,
+) ([]event.Event, error) {
+	if emittedAt.IsZero() {
+		emittedAt = time.Now().UTC()
+	} else {
+		emittedAt = emittedAt.UTC()
+	}
+
+	e := event.Event{
+		ID:          id,
+		Kind:        kind,
+		Source:      sourceName,
+		EmittedAt:   emittedAt,
+		EffectiveAt: effectiveAt,
+		Schema:      schema,
+		Payload:     payload,
+	}
+
+	if err := e.Validate(); err != nil {
+		return nil, err
+	}
+
+	return []event.Event{e}, nil
+}
+
+// ValidateExpectedKinds checks that configured source expected kinds are a subset
+// of the kinds advertised by the built source, when the source exposes kind
+// metadata. If the source does not advertise kinds, the check is skipped.
+func ValidateExpectedKinds(cfg config.SourceConfig, in Input) error {
+	expectedKinds, err := parseExpectedKinds(cfg.ExpectedKinds())
+	if err != nil {
+		return err
+	}
+	if len(expectedKinds) == 0 {
+		return nil
+	}
+
+	advertisedKinds := advertisedSourceKinds(in)
+	if len(advertisedKinds) == 0 {
+		return nil
+	}
+
+	for kind := range expectedKinds {
+		if !advertisedKinds[kind] {
+			return fmt.Errorf(
+				"configured expected kind %q not advertised by source (configured=%v advertised=%v)",
+				kind,
+				sortedKinds(expectedKinds),
+				sortedKinds(advertisedKinds),
+			)
+		}
+	}
+	return nil
+}
+
+func parseExpectedKinds(raw []string) (map[event.Kind]bool, error) {
+	kinds := map[event.Kind]bool{}
+	for i, k := range raw {
+		kind, err := event.ParseKind(k)
+		if err != nil {
+			return nil, fmt.Errorf("invalid expected kind at index %d (%q): %w", i, k, err)
+		}
+		kinds[kind] = true
+	}
+	return kinds, nil
+}
+
+func advertisedSourceKinds(in Input) map[event.Kind]bool {
+	if in == nil {
+		return nil
+	}
+
+	kinds := map[event.Kind]bool{}
+	if ks, ok := in.(KindsSource); ok {
+		for _, kind := range ks.Kinds() {
+			kinds[kind] = true
+		}
+		return kinds
+	}
+
+	if ks, ok := in.(KindSource); ok {
+		kinds[ks.Kind()] = true
+		return kinds
+	}
+
+	return nil
+}
+
+func sortedKinds(kindSet map[event.Kind]bool) []string {
+	out := make([]string, 0, len(kindSet))
+	for kind := range kindSet {
+		out = append(out, string(kind))
+	}
+	sort.Strings(out)
+	return out
+}