/**
 * Logging utilities for fetch-gate
 */
import { type Logger, type LoggerOptions } from "pino";
import type { CircuitBreakerResult, CircuitState } from "./types";
/**
 * Default logger configuration optimized for production use
 */
export declare const DEFAULT_LOGGER_CONFIG: LoggerOptions;
/**
 * Creates a default logger instance with recommended settings for fetch-gate
 */
export declare function createDefaultLogger(options?: LoggerOptions): Logger;
/**
 * Creates a no-op logger that doesn't output anything (useful for testing or when logging is disabled)
 */
export declare function createSilentLogger(): Logger;
/**
 * Logging context for structured logging
 */
export interface LogContext {
    requestId?: string;
    method?: string;
    url?: string;
    baseUrl?: string;
    timeout?: number;
    circuitBreakerState?: CircuitState;
    executionTime?: number;
    [key: string]: any;
}
/**
 * Proxy-specific logging methods with structured context
 */
export declare class ProxyLogger {
    private logger;
    constructor(logger: Logger);
    /**
     * Log request start
     */
    logRequestStart(req: Request, context?: LogContext): void;
    /**
     * Log successful response
     */
    logRequestSuccess(req: Request, res: Response, context?: LogContext): void;
    /**
     * Log request error
     */
    logRequestError(req: Request, error: Error, context?: LogContext): void;
    /**
     * Log circuit breaker events
     */
    logCircuitBreakerEvent(event: "execution_start" | "execution_success" | "execution_failure" | "state_change", req: Request, result?: CircuitBreakerResult, context?: LogContext): void;
    /**
     * Log security validation events
     */
    logSecurityEvent(type: "header_validation" | "query_validation" | "method_validation" | "protocol_validation" | "path_validation", req: Request, details: string, context?: LogContext): void;
    /**
     * Log performance metrics
     */
    logPerformanceMetrics(req: Request, metrics: {
        totalTime: number;
        circuitBreakerTime?: number;
        networkTime?: number;
        cacheHit?: boolean;
    }, context?: LogContext): void;
    /**
     * Log cache operations
     */
    logCacheEvent(event: "hit" | "miss" | "set" | "eviction", key: string, context?: LogContext): void;
    /**
     * Log timeout events
     */
    logTimeout(req: Request, timeout: number, context?: LogContext): void;
    /**
     * Get the underlying Pino logger for custom logging
     */
    getLogger(): Logger;
}
/**
 * Creates a ProxyLogger instance with the given logger
 */
export declare function createProxyLogger(logger: Logger): ProxyLogger;
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