/**
 * Request Context Management
 *
 * Provides request ID generation and context propagation for distributed tracing.
 * Request IDs enable tracking a single request across multiple services and logs.
 *
 * WARNING: This module uses Node.js-specific APIs (async_hooks, crypto).
 * Do NOT import in client-side code or edge runtime.
 */
/**
 * Request context data stored in AsyncLocalStorage
 */
export interface RequestContext {
    /** Unique request identifier */
    requestId: string;
    /** Request start timestamp */
    startTime: number;
    /** User ID (if authenticated) */
    userId?: string;
    /** IP address */
    ip?: string;
    /** User agent */
    userAgent?: string;
    /** Request path */
    path?: string;
    /** Request method */
    method?: string;
    /** Additional metadata */
    metadata?: Record<string, unknown>;
}
/**
 * Generate a new request ID
 * Uses UUID v4 for guaranteed uniqueness
 */
export declare function generateRequestId(): string;
/**
 * Get the current request context
 * Returns undefined if not in a request context
 */
export declare function getRequestContext(): RequestContext | undefined;
/**
 * Get the current request ID
 * Returns undefined if not in a request context
 */
export declare function getRequestId(): string | undefined;
/**
 * Run a function within a request context
 *
 * @param context - Request context data
 * @param fn - Function to run within the context
 * @returns Result of the function
 *
 * @example
 * ```typescript
 * await runInRequestContext(
 *   {
 *     requestId: generateRequestId(),
 *     startTime: Date.now(),
 *     userId: 'user-123',
 *     path: '/api/users',
 *     method: 'GET',
 *   },
 *   async () => {
 *     // All code here has access to request context
 *     const requestId = getRequestId()
 *     logger.info('Processing request', { requestId })
 *   }
 * )
 * ```
 */
export declare function runInRequestContext<T>(context: RequestContext, fn: () => T): T;
/**
 * Update the current request context with additional data
 *
 * @param updates - Partial context updates to merge
 *
 * @example
 * ```typescript
 * updateRequestContext({ userId: 'user-123' })
 * ```
 */
export declare function updateRequestContext(updates: Partial<RequestContext>): void;
/**
 * Extract request ID from various header formats
 *
 * Checks multiple common header names:
 * - x-request-id (standard)
 * - x-correlation-id (correlation pattern)
 * - x-trace-id (OpenTelemetry)
 * - request-id (simple)
 *
 * @param headers - Request headers (any format)
 * @returns Request ID or undefined
 */
export declare function extractRequestId(headers: Record<string, string | string[] | undefined>): string | undefined;
/**
 * Create request context from HTTP request
 *
 * @param options - Request information
 * @returns Request context
 *
 * @example
 * ```typescript
 * const context = createRequestContext({
 *   headers: request.headers,
 *   path: request.url,
 *   method: request.method,
 *   ip: request.ip,
 * })
 * ```
 */
export declare function createRequestContext(options: {
    headers?: Record<string, string | string[] | undefined>;
    path?: string;
    method?: string;
    ip?: string;
    userId?: string;
}): RequestContext;
/**
 * Get request duration in milliseconds
 *
 * @returns Duration in ms, or undefined if not in request context
 */
export declare function getRequestDuration(): number | undefined;
/**
 * Request context headers for propagating across services
 *
 * Use these when making HTTP requests to other services to maintain trace continuity
 *
 * @returns Headers object with request ID
 *
 * @example
 * ```typescript
 * const response = await fetch('https://api.example.com/users', {
 *   headers: {
 *     ...getRequestHeaders(),
 *     'Authorization': 'Bearer token',
 *   }
 * })
 * ```
 */
export declare function getRequestHeaders(): Record<string, string>;
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