import { CloudWatchLogs, type CreateLogStreamRequest, type InputLogEvent } from "@aws-sdk/client-cloudwatch-logs";
import type { RegionInputConfig } from "@smithy/config-resolver/dist-types/regionConfig/resolveRegionConfig";
import type { AwsCredentialIdentity } from "@smithy/types/dist-types/identity/awsCredentialIdentity";
import type log4js from "log4js";
export interface Config extends CreateLogStreamRequest, Pick<RegionInputConfig, "region">, Pick<AwsCredentialIdentity, "accessKeyId" | "secretAccessKey" | "sessionToken"> {
    /**
     * defaults to http://npm.im/log4js-layout-json
     */
    layout?: log4js.Layout;
    /**
     * Maximum number of log events to include in a single batch when sending.
     * Once the batch size is reached, it will be sent to CloudWatch.
     */
    batchSize: number;
    /**
     * Maximum time (in milliseconds) to wait before sending a batch of logs,
     * regardless of the batch size. If the timeout is reached before the batch
     * size is met, the logs will be sent.
     */
    bufferTimeout: number;
    /**
     * required policy:
     * - logs:CreateLogGroup
     * - logs:CreateLogStream
     */
    createResources?: boolean;
}
declare module "log4js" {
    interface Appenders {
        CloudwatchAppender: {
            type: "log4js-appender-cloudwatch";
        } & Config;
    }
}
export declare class LogBuffer {
    private _config;
    private _onReleaseCallback;
    private _timer;
    private _logs;
    constructor(_config: Config, _onReleaseCallback: (logs: Array<InputLogEvent>) => void);
    /**
     * Pushes a log message to the internal log buffer.
     *
     * @param message - The log message to be pushed. If it's an
     *     object, it will be converted to a JSON string.
     * f
     * @param timestamp - The timestamp of the log
     *     message. If not provided, the current timestamp will be used.
     */
    push(message: string, timestamp?: number): void;
    /**
     * Releases the logs and clears the timer.
     */
    release(): void;
}
export declare class CloudwatchAppender {
    private _config;
    private _layout;
    private _logEventBuffer;
    private _cloudwatchClient;
    constructor(_config: Config, _layout: log4js.LayoutFunction, _logEventBuffer: LogBuffer, _cloudwatchClient: CloudWatchLogs);
    /**
     * Creates log groups and streams in CloudWatch if they don't exist.
     * If resources already exist, the creation requests are silently ignored.
     */
    private createLogGroups;
    /**
     * Verifies that the configured log groups and streams exist in CloudWatch.
     *
     * @throws {ConfigError} If log group/stream doesn't exist or credentials are invalid
     */
    private initializeLogGroups;
    /**
     * Returns the appender function that will be used by log4js.
     *
     * The function processes logging events by formatting them using the configured layout
     * and buffering them for batch processing.
     *
     * @returns {log4js.AppenderFunction} The function that will handle logging events
     */
    appenderFunction(): log4js.AppenderFunction;
}
export declare class ConfigError extends Error {
    constructor(msg: string, cause?: unknown);
}
export declare function createLogEventHandler(cloudwatchClient: CloudWatchLogs, config: Config): LogBuffer["_onReleaseCallback"];
export declare function configure(config: Config, layouts: log4js.LayoutsParam, _findAppender: () => log4js.AppenderFunction, _levels: log4js.Levels): log4js.AppenderFunction;