import { BasePlugin } from '@opentelemetry/core';
import * as express from 'express';
import { ExpressPluginConfig } from './types';
/**
 * This symbol is used to mark express layer as being already instrumented
 * since its possible to use a given layer multiple times (ex: middlewares)
 */
export declare const kLayerPatched: unique symbol;
/** Express instrumentation plugin for OpenTelemetry */
export declare class ExpressPlugin extends BasePlugin<typeof express> {
    readonly moduleName: string;
    static readonly component = "express";
    readonly supportedVersions: string[];
    protected _config: ExpressPluginConfig;
    protected _logger: import("@opentelemetry/api").DiagAPI;
    constructor(moduleName: string);
    /**
     * Patches Express operations.
     */
    protected patch(): any;
    /** Unpatches all Express patched functions. */
    unpatch(): void;
    /**
     * Get the patch for Router.route function
     * @param original
     */
    private _getRoutePatch;
    /**
     * Get the patch for Router.use function
     * @param original
     */
    private _getRouterUsePatch;
    /**
     * Get the patch for Application.use function
     * @param original
     */
    private _getAppUsePatch;
    /** Patch each express layer to create span and propagate context */
    private _applyPatch;
}
export declare const plugin: ExpressPlugin;