import type { Plugin } from './app';
import { InjectionToken } from './di';
/** A single readiness check. */
export interface HealthCheck {
    /** Identifier reported in the `/ready` payload. */
    name: string;
    /** Return truthy if healthy; a falsy result or a throw marks it down. */
    check: () => boolean | Promise<boolean>;
}
/**
 * Multi-injection token for readiness checks. Bind a {@link HealthCheck} (a
 * value or an `@injectable` class that implements it) as a provider and
 * {@link health} collects every one it finds, alongside any passed explicitly.
 *
 * ```ts
 * createApp({
 *   providers: [{ provide: HEALTH_CHECK, useClass: DbHealth }],
 *   plugins: [health()],
 * })
 * ```
 */
export declare const HEALTH_CHECK: InjectionToken<HealthCheck>;
/** Options for the {@link health} plugin. */
export interface HealthOptions {
    /** Extra readiness checks, run on every `/ready` request alongside any {@link HEALTH_CHECK} providers; all run concurrently and every one must pass for a `200`. */
    checks?: HealthCheck[];
    /** Liveness path (the process is serving). Default `/health`. */
    livenessPath?: string;
    /** Readiness path (dependencies are up). Default `/ready`. */
    readinessPath?: string;
}
/**
 * Plugin: mount liveness and readiness probes. `/health` answers `200` whenever
 * the process is serving (liveness). `/ready` runs every check — those passed in
 * {@link HealthOptions.checks} plus any {@link HEALTH_CHECK} providers bound in
 * the container — and answers `200` when all pass or `503` when any fails, with
 * a per-check breakdown — the shape a load balancer or orchestrator expects.
 *
 * ```ts
 * const app = await createApp({
 *   plugins: [health({ checks: [{ name: 'db', check: () => db.ping() }] })],
 * })
 * // GET /health → 200 {status:"up"}; GET /ready → 200/503 with per-check status
 * ```
 *
 * @param options - Endpoint paths and any explicit readiness checks.
 * @returns A plugin serving the liveness and readiness probe endpoints.
 */
export declare function health(options?: HealthOptions): Plugin;
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