import type { DataSource, EntityManager } from 'typeorm';
/**
 * Runs the provided callback in a readonly database context backed by a slave query runner.
 *
 * If a readonly context is already active, the callback is reused within that context instead of
 * creating a new query runner. Starting a readonly context from inside a transaction is rejected
 * because it would break the current transactional guarantees. Within the callback, injected
 * TypeORM repositories automatically resolve against the active readonly manager, so repository
 * operations also use the readonly query runner without requiring manual rebinding.
 *
 * @template T
 * @param dataSource The TypeORM data source used to create the readonly query runner.
 * @param runInReadonly Async callback that receives the readonly entity manager for all database
 * access. Injected TypeORM repositories used inside this callback automatically participate in the
 * same readonly context.
 * @returns The value returned by `runInReadonly`.
 * @throws {Error} If called while a transaction context is active.
 * @throws {QueryRunnerProviderAlreadyReleasedError} If the current readonly context references a released query runner.
 */
export declare function readonly<T>(dataSource: DataSource, runInReadonly: (entityManager: EntityManager) => Promise<T>): Promise<T>;
export declare function createReadonlyManagerProxy(defaultManager: EntityManager): EntityManager;