@aws-lambda-powertools/parameters/lib/esm/base/BaseProvider.d.ts

The parameters package for the Powertools for AWS Lambda (TypeScript) library

import { EnvironmentVariablesService } from '../config/EnvironmentVariablesService.js';
import type { BaseProviderConstructorOptions, BaseProviderInterface, GetMultipleOptionsInterface, GetOptionsInterface } from '../types/BaseProvider.js';
import { ExpirableValue } from './ExpirableValue.js';
/**
 * Base class for all providers.
 *
 * As an abstract class, it should not be used directly, but rather extended by other providers.
 *
 * It implements the common logic for all providers, such as caching, transformation, etc.
 * Each provider that extends this class must implement the `_get` and `_getMultiple` abstract methods.
 *
 * These methods are responsible for retrieving the values from the underlying parameter store. They are
 * called by the `get` and `getMultiple` methods, which are responsible for caching and transformation.
 *
 * If there are multiple calls to the same parameter but in a different transform, they will be stored multiple times.
 * This allows us to optimize by transforming the data only once per retrieval, thus there is no need to transform cached values multiple times.
 *
 * However, this means that we need to make multiple calls to the underlying parameter store if we need to return it in different transforms.
 *
 * Since the number of supported transform is small and the probability that a given parameter will always be used in a specific transform,
 * this should be an acceptable tradeoff.
 */
declare abstract class BaseProvider implements BaseProviderInterface {
    envVarsService: EnvironmentVariablesService;
    protected client: unknown;
    protected store: Map<string, ExpirableValue>;
    constructor({ awsSdkV3Client, clientConfig, awsSdkV3ClientPrototype, }: BaseProviderConstructorOptions);
    /**
     * Add a value to the cache.
     *
     * @param {string} key - Key of the cached value
     * @param {string | Uint8Array | Record<string, unknown>} value - Value to be cached
     * @param {number} maxAge - Maximum age in seconds for the value to be cached
     */
    addToCache(key: string, value: unknown, maxAge: number): void;
    /**
     * Clear the cache.
     */
    clearCache(): void;
    /**
     * Retrieve a parameter value or return the cached value.
     *
     * @param {string} name - Parameter name
     * @param {GetOptionsInterface} options - Options to configure maximum age, trasformation, AWS SDK options, or force fetch
     */
    get(name: string, options?: GetOptionsInterface): Promise<unknown | undefined>;
    /**
     * Retrieve multiple parameter values or return the cached values.
     *
     * @param {string} path - Parameters path
     * @param {GetMultipleOptionsInterface} options - Options to configure maximum age, trasformation, AWS SDK options, or force fetch
     * @returns
     */
    getMultiple(path: string, options?: GetMultipleOptionsInterface): Promise<unknown>;
    /**
     * Check whether a key has expired in the cache or not.
     *
     * It returns true if the key is expired or not present in the cache.
     *
     * @param {string} key - Stringified representation of the key to retrieve
     */
    hasKeyExpiredInCache(key: string): boolean;
    /**
     * Retrieve parameter value from the underlying parameter store.
     *
     * @param {string} name - Parameter name
     * @param {unknown} options - Options to pass to the underlying implemented method
     */
    protected abstract _get(name: string, options?: unknown): Promise<unknown>;
    /**
     * Retrieve multiple parameter values from the underlying parameter store.
     *
     * @param {string} path - Parameter name
     * @param {unknown} options - Options to pass to the underlying implementated method
     */
    protected abstract _getMultiple(path: string, options?: unknown): Promise<Record<string, unknown> | undefined>;
}
export { BaseProvider };
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