/**
 * Health service handles health check operations.
 */
import { EventEmitter } from 'events';
import { ServiceContext } from './service-context';
import { HealthStatus } from '../types';
/**
 * Health watcher interface for streaming health updates.
 * Emits 'status' events with HealthStatus and 'error' events on failure.
 */
export interface HealthWatcher extends EventEmitter {
    /** Stop watching health updates */
    stop(): void;
}
/**
 * Health service for checking service health.
 */
export declare class HealthService {
    private ctx;
    constructor(ctx: ServiceContext);
    /**
     * Check the health of a service.
     */
    healthCheck(service?: string): Promise<HealthStatus>;
    /**
     * Watch health status changes via server-side streaming.
     * Returns a HealthWatcher that emits 'status' events with HealthStatus values.
     * Call stop() to cancel the stream.
     *
     * @param service - Optional service name to watch
     * @returns HealthWatcher - EventEmitter with stop() method
     *
     * @example
     * ```typescript
     * const watcher = healthService.watch();
     * watcher.on('status', (status: HealthStatus) => {
     *   console.log('Health status:', status);
     * });
     * watcher.on('error', (err) => {
     *   console.error('Watch error:', err);
     * });
     * watcher.on('end', () => {
     *   console.log('Watch stream ended');
     * });
     * // Later, to stop watching:
     * watcher.stop();
     * ```
     */
    watch(service?: string): HealthWatcher;
}