init ingestion

ingestion/ingest/internal/dedup/dedup.go

@@ -0,0 +1,50 @@
+// Package dedup provides idempotent event acceptance via Redis SETNX.
+//
+// Key shape: dedup:{workspace_id}:{message_id}
+// TTL:       24h by default (configurable)
+//
+// CheckAndSet returns true when the message_id is new (first time seen).
+// If it returns false the caller MUST drop the event silently and return 200.
+package dedup
+
+import (
+	"context"
+	"fmt"
+	"time"
+
+	"github.com/redis/rueidis"
+)
+
+type Dedup interface {
+	CheckAndSet(ctx context.Context, workspaceID, messageID string) (bool, error)
+}
+
+type redisDedup struct {
+	client rueidis.Client
+	ttl    time.Duration
+}
+
+func New(client rueidis.Client, ttl time.Duration) Dedup {
+	return &redisDedup{client: client, ttl: ttl}
+}
+
+func key(workspaceID, messageID string) string {
+	return fmt.Sprintf("dedup:%s:%s", workspaceID, messageID)
+}
+
+func (d *redisDedup) CheckAndSet(ctx context.Context, workspaceID, messageID string) (bool, error) {
+	k := key(workspaceID, messageID)
+	cmd := d.client.B().Set().Key(k).Value("1").
+		Nx().
+		Ex(d.ttl).
+		Build()
+	resp := d.client.Do(ctx, cmd)
+	if err := resp.Error(); err != nil {
+		return false, fmt.Errorf("dedup setnx: %w", err)
+	}
+	// SET with NX returns "OK" when set, nil reply when key already exists.
+	if resp.IsNil() {
+		return false, nil
+	}
+	return true, nil
+}