import { LogContext } from '@balena/jellyfish-logger';
import type { AutumnDBSession, Kernel } from 'autumndb';
import * as graphileWorker from 'graphile-worker';
import type { Pool } from 'pg';
import type { ActionRequestContract } from '../types';
export declare type OnMessageEventHandler = (payload: ActionRequestContract) => Promise<void>;
export interface QueueConsumer {
    initializeWithEventHandler: (logContext: LogContext, onMessageEventHandler: OnMessageEventHandler) => Promise<void>;
    run: (logContext: LogContext, onMessageEventHandler: OnMessageEventHandler, retries?: number) => Promise<boolean>;
    cancel: () => Promise<void>;
    postResults: (logContext: LogContext, actionRequest: ActionRequestContract, results: PostResults) => Promise<ActionRequestContract>;
}
export interface PostResults {
    data: string | {
        originator?: string;
        [key: string]: any;
    };
    error: boolean;
}
export declare class Consumer implements QueueConsumer {
    private kernel;
    private pool;
    private session;
    messagesBeingHandled: number;
    graphileRunner: graphileWorker.Runner | null;
    constructor(kernel: Kernel, pool: Pool, session: AutumnDBSession);
    initializeWithEventHandler(logContext: LogContext, onMessageEventHandler: OnMessageEventHandler): Promise<void>;
    run(logContext: LogContext, onMessageEventHandler: OnMessageEventHandler, retries?: number): Promise<boolean>;
    cancel(): Promise<void>;
    /**
     * @summary Post execution results
     * @function
     * @public
     *
     * @param logContext - log context
     * @param actionRequest - action request contract
     * @returns execute event contract
     */
    postResults(logContext: LogContext, actionRequest: ActionRequestContract, results: PostResults): Promise<ActionRequestContract>;
}