/**
 * Wrapper for accessing settings in DRL apps and modules.
 */
export declare class DrlSettings {
    private static WhiteList;
    /**
     * Detects if importing .env files is allowed. This requires that the
     * environment variable DRL_HOST_ENV be set to CI or LOCAL.
     */
    static useEnvFile(): boolean;
    /**
     * Initializes and validates anticipated keys.
     * @param keys - A list of keys that are going to be used
     * @param filePath - An optional
     */
    static initSettings(keys: Array<string>, filePath?: string): void;
    /**
     * Lists all available keys
     */
    static getSettingKeys(): string[];
    /**
     * Grabs setting value for a given key.
     * @param key - key to look up
     * @throws - If key has not be properly registered or doesn't exist in process.env
     */
    static getSetting(key: string): string;
    private static warn;
    private static log;
    private static checkKeys;
}