import { TransactionalConnection } from '../../connection/transactional-connection';
import { ScheduledTask } from '../../scheduler';
/**
 * @description
 * This service finds and cleans stale locks, which can occur if a worker instance is
 * non-gracefully shut down while a task is ongoing, and the lock is never released.
 *
 * Failure to clean these stale locks will prevent the task from ever running again, since
 * workers will assume it is locked by another processes and will ignore it.
 */
export declare class StaleTaskService {
    private connection;
    private taskIntervalMap;
    constructor(connection: TransactionalConnection);
    /**
     * @description
     * Cleans stale task locks from the database.
     */
    cleanStaleLocksForTask(task: ScheduledTask): Promise<void>;
    private fetchLockedTask;
    /**
     * Returns the interval in ms between one run of the task, and the next.
     */
    getScheduleIntervalMs(task: ScheduledTask): number;
    private isStale;
    private clearStaleLock;
}