import { OnModuleInit, OnModuleDestroy } from '@nestjs/common';
import { DataSource } from 'typeorm';
export declare class DatabaseKeepAliveService implements OnModuleInit, OnModuleDestroy {
    private readonly dataSources;
    private readonly logger;
    private intervalHandle;
    private readonly PING_INTERVAL_MS;
    constructor(dataSources: DataSource[]);
    onModuleInit(): void;
    onModuleDestroy(): void;
    private pingAll;
    private pingOne;
    private tryReconnect;
}