import type { ClientOptions } from '@grpc/grpc-js';
/** Contains the default keepalive interval in milliseconds. */
export declare const DEFAULT_KEEPALIVE_TIME_MS = 20000;
/** Contains the default keepalive timeout in milliseconds. */
export declare const DEFAULT_KEEPALIVE_TIMEOUT_MS = 10000;
/** Specifies whether the default permits keepalive without an active call. */
export declare const DEFAULT_KEEPALIVE_PERMIT_WITHOUT_STREAM = true;
/** Contains the keepalive interval environment-variable name. */
export declare const ENV_GRPC_KEEPALIVE_TIME = "NEBIUS_GRPC_KEEPALIVE_TIME";
/** Contains the keepalive timeout environment-variable name. */
export declare const ENV_GRPC_KEEPALIVE_TIMEOUT = "NEBIUS_GRPC_KEEPALIVE_TIMEOUT";
/** Contains the permit-without-stream environment-variable name. */
export declare const ENV_GRPC_KEEPALIVE_PERMIT_WITHOUT_STREAM = "NEBIUS_GRPC_KEEPALIVE_PERMIT_WITHOUT_STREAM";
/**
 * Configures gRPC keepalive.
 *
 * Explicit options override the `NEBIUS_GRPC_KEEPALIVE_*` environment
 * variables. When you supply an options object, omitted fields use SDK
 * defaults instead of environment values. Set {@link KeepaliveOptions.timeMs}
 * to `0`, or set
 * {@link https://nebius.github.io/js-sdk/interfaces/sdk.SDKOptions.html#keepalive | SDKOptions.keepalive}
 * to `false`, to disable keepalive.
 *
 * Keepalive pings help detect a broken connection during a long-lived
 * process. A server or network can reject pings that are too frequent.
 *
 * @example
 * ```ts
 * import { SDK } from '@nebius/js-sdk';
 *
 * const sdk = new SDK({
 *   keepalive: {
 *     timeMs: 30_000,
 *     timeoutMs: 10_000,
 *     permitWithoutStream: true,
 *   },
 *   userAgentPrefix: 'example-application/1.0',
 * });
 * ```
 */
export interface KeepaliveOptions {
    /** Sets the keepalive interval in milliseconds. */
    timeMs?: number;
    /** Sets the keepalive timeout in milliseconds. */
    timeoutMs?: number;
    /** Specifies whether to send keepalive pings without an active call. */
    permitWithoutStream?: boolean;
}
/**
 * Defines the validated keepalive settings used for each new gRPC client.
 *
 * Use {@link keepaliveConfigFromOptions} or {@link keepaliveConfigFromEnv} to
 * create this value.
 */
export interface KeepaliveConfig {
    /** Specifies whether keepalive is enabled. */
    enabled: boolean;
    /** Contains the keepalive interval in milliseconds. */
    timeMs: number;
    /** Contains the keepalive timeout in milliseconds. */
    timeoutMs: number;
    /** Specifies whether to send keepalive pings without an active call. */
    permitWithoutStream: boolean;
}
/**
 * Defines an environment-like object that configures keepalive.
 *
 * Tests and embedded runtimes can pass a plain object instead of using
 * `process.env`.
 */
export type Environment = Record<string, string | undefined>;
/**
 * Returns a new copy of the default gRPC keepalive configuration.
 *
 * You can modify the returned object without changing later calls.
 */
export declare function defaultKeepaliveConfig(): KeepaliveConfig;
/**
 * Reads and validates gRPC keepalive environment variables.
 *
 * Duration values use Go duration syntax, such as `20s`, `500ms`, or `1m`.
 * Set {@link ENV_GRPC_KEEPALIVE_TIME} to `0` to disable keepalive.
 *
 * @example
 * ```ts
 * const config = keepaliveConfigFromEnv({
 *   NEBIUS_GRPC_KEEPALIVE_TIME: '30s',
 *   NEBIUS_GRPC_KEEPALIVE_TIMEOUT: '10s',
 *   NEBIUS_GRPC_KEEPALIVE_PERMIT_WITHOUT_STREAM: 'true',
 * });
 * ```
 *
 * @throws {Error} A value has invalid duration or Boolean syntax.
 */
export declare function keepaliveConfigFromEnv(env?: Environment): KeepaliveConfig;
/**
 * Creates and validates a gRPC keepalive configuration from SDK options.
 *
 * `undefined` reads environment variables. `false` disables keepalive. An
 * options object uses SDK defaults for fields that it omits.
 *
 * @throws {Error} A millisecond value is negative, non-finite, or not an integer.
 */
export declare function keepaliveConfigFromOptions(options: KeepaliveOptions | false | undefined): KeepaliveConfig;
/**
 * Converts a validated keepalive configuration to gRPC client options.
 *
 * A disabled configuration returns an empty object. The SDK applies the
 * returned options when it creates a channel.
 */
export declare function keepaliveClientOptions(cfg: KeepaliveConfig): Partial<ClientOptions>;
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