feat: persist queue heartbeat and cancel mutations

server/store/queue_sql.go

@@ -25,6 +25,16 @@ FOR UPDATE`
     protocol_version, enqueued_at, expires_at, revision
 FROM queue_tickets
 WHERE ticket_id = $1 AND player_id = $2`
+	QueueTicketHeartbeatSQL = `UPDATE queue_tickets SET revision = revision + 1,
+    expires_at = $4 + INTERVAL '30 seconds'
+WHERE ticket_id = $1 AND player_id = $2 AND revision = $3
+  AND state IN ('QUEUED', 'PROPOSED') AND expires_at > $4
+RETURNING ticket_id, player_id, playlist, state, client_build, protocol_version, enqueued_at, expires_at, revision`
+	QueueTicketCancelSQL = `UPDATE queue_tickets SET state = 'CANCELLED',
+    revision = revision + 1, expires_at = $4
+WHERE ticket_id = $1 AND player_id = $2 AND revision = $3
+  AND state NOT IN ('COMPLETED', 'CANCELLED', 'EXPIRED', 'FAILED')
+RETURNING ticket_id, player_id, playlist, state, client_build, protocol_version, enqueued_at, expires_at, revision`
 )
 
 func CreateQueueTicket(ctx context.Context, db *sql.DB, ticketID, playerID, idempotencyKey string, spec domain.QueueSpec, now time.Time) (domain.QueueTicket, error) {
@@ -92,6 +102,58 @@ func GetQueueTicket(ctx context.Context, db *sql.DB, playerID, ticketID string)
 	return queueTicketRecordToDomain(record), nil
 }
 
+func HeartbeatQueueTicket(ctx context.Context, db *sql.DB, playerID, ticketID, idempotencyKey string, expectedRevision uint64, now time.Time) (domain.QueueTicket, error) {
+	return mutateQueueTicket(ctx, db, playerID, ticketID, idempotencyKey, expectedRevision, now, "heartbeat", QueueTicketHeartbeatSQL)
+}
+
+func CancelQueueTicket(ctx context.Context, db *sql.DB, playerID, ticketID, idempotencyKey string, expectedRevision uint64, now time.Time) (domain.QueueTicket, error) {
+	return mutateQueueTicket(ctx, db, playerID, ticketID, idempotencyKey, expectedRevision, now, "cancel", QueueTicketCancelSQL)
+}
+
+func mutateQueueTicket(ctx context.Context, db *sql.DB, playerID, ticketID, idempotencyKey string, expectedRevision uint64, now time.Time, operation, mutationSQL string) (ticket domain.QueueTicket, err error) {
+	if db == nil || playerID == "" || ticketID == "" || len(idempotencyKey) < 16 || len(idempotencyKey) > 128 || now.IsZero() || (operation != "heartbeat" && operation != "cancel") {
+		return domain.QueueTicket{}, fmt.Errorf("invalid queue mutation arguments")
+	}
+	digest := sha256.Sum256([]byte(fmt.Sprintf("%s|%s|%s|%d", operation, playerID, ticketID, expectedRevision)))
+	err = RunSerializable(ctx, db, DefaultSerializableAttempts, func(ctx context.Context, tx *sql.Tx) error {
+		result, err := tx.ExecContext(ctx, QueueIdempotencyInsertSQL, QueueIdempotencyScope+"."+operation, idempotencyKey, digest[:], []byte("{}"))
+		if err != nil {
+			return err
+		}
+		inserted, err := result.RowsAffected()
+		if err != nil {
+			return err
+		}
+		if inserted == 0 {
+			var priorDigest, priorResult []byte
+			if err := tx.QueryRowContext(ctx, QueueIdempotencySelectSQL, QueueIdempotencyScope+"."+operation, idempotencyKey).Scan(&priorDigest, &priorResult); err != nil {
+				return err
+			}
+			if !bytes.Equal(priorDigest, digest[:]) {
+				return fmt.Errorf("queue mutation idempotency conflict")
+			}
+			var prior queueTicketRecord
+			if err := json.Unmarshal(priorResult, &prior); err != nil {
+				return fmt.Errorf("invalid stored queue result: %w", err)
+			}
+			ticket = queueTicketRecordToDomain(prior)
+			return nil
+		}
+		var record queueTicketRecord
+		if err := tx.QueryRowContext(ctx, mutationSQL, ticketID, playerID, expectedRevision, now).Scan(&record.TicketID, &record.PlayerID, &record.Playlist, &record.State, &record.ClientBuild, &record.ProtocolVersion, &record.EnqueuedAt, &record.ExpiresAt, &record.Revision); err != nil {
+			return fmt.Errorf("queue mutation rejected: %w", err)
+		}
+		ticket = queueTicketRecordToDomain(record)
+		stored, err := json.Marshal(record)
+		if err != nil {
+			return err
+		}
+		_, err = tx.ExecContext(ctx, `UPDATE idempotency_keys SET result = $3 WHERE scope = $1 AND idempotency_key = $2`, QueueIdempotencyScope+"."+operation, idempotencyKey, stored)
+		return err
+	})
+	return ticket, err
+}
+
 func queueTicketRecordFromDomain(ticket domain.QueueTicket) queueTicketRecord {
 	return queueTicketRecord{ticket.TicketID, ticket.PlayerID, string(ticket.Playlist), string(ticket.State), ticket.Candidate.ClientBuild, ticket.Candidate.ProtocolVersion, ticket.EnqueuedAt, ticket.ExpiresAt, ticket.Revision}
 }