Changeset 0.32.0 (#206)

server/store/postgres/ratelimit.go

@@ -0,0 +1,36 @@
+package postgres
+
+import (
+	"context"
+	"fmt"
+	"time"
+)
+
+// RateLimitStore manages distributed rate limit counters in Postgres.
+// v0.32.0: fixed-window counter — upsert per-second bucket, check burst.
+type RateLimitStore struct{}
+
+func NewRateLimitStore() *RateLimitStore { return &RateLimitStore{} }
+
+func (s *RateLimitStore) Allow(ctx context.Context, key string, rate float64, burst int) (bool, error) {
+	// Upsert the current-second window counter and return the new token count.
+	var tokens float64
+	err := DB.QueryRowContext(ctx, `
+		INSERT INTO rate_limit_counters (key, window_start, tokens)
+		VALUES ($1, date_trunc('second', NOW()), 1)
+		ON CONFLICT (key, window_start)
+		DO UPDATE SET tokens = rate_limit_counters.tokens + 1
+		RETURNING tokens`, key).Scan(&tokens)
+	if err != nil {
+		return false, fmt.Errorf("rate limit upsert: %w", err)
+	}
+	return tokens <= float64(burst), nil
+}
+
+func (s *RateLimitStore) Cleanup(ctx context.Context, maxAge time.Duration) error {
+	_, err := DB.ExecContext(ctx, `
+		DELETE FROM rate_limit_counters
+		WHERE window_start < NOW() - $1 * INTERVAL '1 second'`,
+		int(maxAge.Seconds()))
+	return err
+}