@aws-lambda-powertools/parameters
Version:
The parameters package for the Powertools for AWS Lambda (TypeScript) library
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TypeScript
import { AppConfigDataClient } from '@aws-sdk/client-appconfigdata';
import { BaseProvider } from '../base/BaseProvider.js';
import type { AppConfigGetOptions, AppConfigGetOutput, AppConfigProviderOptions } from '../types/AppConfigProvider.js';
/**
* ## Intro
* The Parameters utility provides an AppConfigProvider that allows to retrieve configuration profiles from AWS AppConfig.
*
* ## Getting started
*
* This utility supports AWS SDK v3 for JavaScript only (`@aws-sdk/client-appconfigdata`). This allows the utility to be modular, and you to install only
* the SDK packages you need and keep your bundle size small.
*
* ## Basic usage
*
* @example
* ```typescript
* import { AppConfigProvider } from '@aws-lambda-powertools/parameters/appconfig';
*
* const configProvider = new AppConfigProvider({
* application: 'my-app',
* environment: 'prod',
* });
*
* export const handler = async (): Promise<void> => {
* // Retrieve a configuration profile
* const encodedConfig = await configProvider.get('my-config');
* const config = new TextDecoder('utf-8').decode(encodedConfig);
* };
* ```
* If you want to retrieve configs without customizing the provider, you can use the {@link getAppConfig} function instead.
*
* ## Advanced usage
*
* ### Caching
*
* By default, the provider will cache parameters retrieved in-memory for 5 seconds.
* You can adjust how long values should be kept in cache by using the `maxAge` parameter.
*
* @example
* ```typescript
* import { AppConfigProvider } from '@aws-lambda-powertools/parameters/appconfig';
*
* const configProvider = new AppConfigProvider({
* application: 'my-app',
* environment: 'prod',
* });
*
* export const handler = async (): Promise<void> => {
* // Retrieve a configuration profile and cache it for 10 seconds
* const encodedConfig = await configProvider.get('my-config', { maxAge: 10 });
* const config = new TextDecoder('utf-8').decode(encodedConfig);
* };
* ```
*
* If instead you'd like to always ensure you fetch the latest parameter from the store regardless if already available in cache, use the `forceFetch` parameter.
*
* @example
* ```typescript
* import { AppConfigProvider } from '@aws-lambda-powertools/parameters/appconfig';
*
* const configProvider = new AppConfigProvider({
* application: 'my-app',
* environment: 'prod',
* });
*
* export const handler = async (): Promise<void> => {
* // Retrieve a config and always fetch the latest value
* const config = await configProvider.get('my-config', { forceFetch: true });
* const config = new TextDecoder('utf-8').decode(encodedConfig);
* };
* ```
*
* ### Transformations
*
* For configurations stored as freeform JSON, Freature Flag, you can use the transform argument for deserialization. This will return a JavaScript object instead of a string.
*
* @example
* ```typescript
* import { AppConfigProvider } from '@aws-lambda-powertools/parameters/appconfig';
*
* const configProvider = new AppConfigProvider({
* application: 'my-app',
* environment: 'prod',
* });
*
* export const handler = async (): Promise<void> => {
* // Retrieve a JSON config or Feature Flag and parse it as JSON
* const config = await configProvider.get('my-config', { transform: 'json' });
* };
* ```
*
* For configurations that are instead stored as base64-encoded binary data, you can use the transform argument set to `binary` for decoding. This will return a decoded string.
*
* @example
* ```typescript
* import { AppConfigProvider } from '@aws-lambda-powertools/parameters/appconfig';
*
* const configProvider = new AppConfigProvider({
* application: 'my-app',
* environment: 'prod',
* });
*
* export const handler = async (): Promise<void> => {
* // Retrieve a base64-encoded string and decode it
* const config = await configProvider.get('my-config', { transform: 'binary' });
* };
* ```
*
* ### Extra SDK options
*
* When retrieving a configuration profile, you can pass extra options to the AWS SDK v3 for JavaScript client by using the `sdkOptions` parameter.
*
* @example
* ```typescript
* import { AppConfigProvider } from '@aws-lambda-powertools/parameters/appconfig';
*
* const configProvider = new AppConfigProvider({
* application: 'my-app',
* environment: 'prod',
* });
*
* export const handler = async (): Promise<void> => {
* // Retrieve a config and pass extra options to the AWS SDK v3 for JavaScript client
* const config = await configProvider.get('my-config', {
* sdkOptions: {
* RequiredMinimumPollIntervalInSeconds: 60,
* },
* });
* const config = new TextDecoder('utf-8').decode(encodedConfig);
* };
* ```
*
* This object accepts the same options as the [AWS SDK v3 for JavaScript AppConfigData client](https://docs.aws.amazon.com/AWSJavaScriptSDK/v3/latest/clients/client-appconfigdata/interfaces/startconfigurationsessioncommandinput.html).
*
* ### Customize AWS SDK v3 for JavaScript client
*
* By default, the provider will create a new AppConfigData client using the default configuration.
*
* You can customize the client by passing a custom configuration object to the provider.
*
* @example
* ```typescript
* import { AppConfigProvider } from '@aws-lambda-powertools/parameters/appconfig';
*
* const configProvider = new AppConfigProvider({
* application: 'my-app',
* environment: 'prod',
* clientConfig: { region: 'eu-west-1' },
* });
* ```
*
* This object accepts the same options as the [AWS SDK v3 for JavaScript AppConfig Data client](https://docs.aws.amazon.com/AWSJavaScriptSDK/v3/latest/clients/client-appconfigdata/interfaces/appconfigdataclientconfig.html).
*
* Otherwise, if you want to use a custom client altogether, you can pass it to the provider.
*
* @example
* ```typescript
* import { AppConfigProvider } from '@aws-lambda-powertools/parameters/appconfig';
* import { AppConfigDataClient } from '@aws-sdk/client-appconfigdata';
*
* const client = new AppConfigDataClient({ region: 'eu-west-1' });
* const configProvider = new AppConfigProvider({
* application: 'my-app',
* environment: 'prod',
* awsSdkV3Client: client,
* });
* ```
*
* This object must be an instance of the [AWS SDK v3 for JavaScript AppConfig Data client](https://docs.aws.amazon.com/AWSJavaScriptSDK/v3/latest/clients/client-appconfigdata/classes/appconfigdataclient.html).
*
* For more usage examples, see [our documentation](https://docs.powertools.aws.dev/lambda/typescript/latest/utilities/parameters/).
*/
declare class AppConfigProvider extends BaseProvider {
client: AppConfigDataClient;
protected configurationTokenStore: Map<string, {
value: string;
expiration: number;
}>;
protected valueStore: Map<string, Uint8Array<ArrayBufferLike>>;
private application?;
private environment;
/**
* It initializes the AppConfigProvider class.
* *
* @param {AppConfigProviderOptions} options - The configuration object.
*/
constructor(options: AppConfigProviderOptions);
/**
* Retrieve a configuration profile from AWS AppConfig.
*
* @example
* ```typescript
* import { AppConfigProvider } from '@aws-lambda-powertools/parameters/appconfig';
*
* const configProvider = new AppConfigProvider({
* application: 'my-app',
* environment: 'prod',
* });
*
* export const handler = async (): Promise<void> => {
* // Retrieve a configuration profile
* const encodedConfig = await configProvider.get('my-config');
* const config = new TextDecoder('utf-8').decode(encodedConfig);
* };
* ```
*
* You can customize the retrieval of the configuration profile by passing options to the function:
* * `maxAge` - The maximum age of the value in cache before fetching a new one (in seconds) (default: 5)
* * `forceFetch` - Whether to always fetch a new value from the store regardless if already available in cache
* * `transform` - Whether to transform the value before returning it. Supported values: `json`, `binary`
* * `sdkOptions` - Extra options to pass to the AWS SDK v3 for JavaScript client
*
* For usage examples check {@link AppConfigProvider}.
*
* @param {string} name - The name of the configuration profile or its ID
* @param {AppConfigGetOptions} options - Options to configure the provider
* @see https://docs.powertools.aws.dev/lambda/typescript/latest/utilities/parameters/
*/
get<ExplicitUserProvidedType = undefined, InferredFromOptionsType extends AppConfigGetOptions | undefined = AppConfigGetOptions>(name: string, options?: InferredFromOptionsType & AppConfigGetOptions): Promise<AppConfigGetOutput<ExplicitUserProvidedType, InferredFromOptionsType> | undefined>;
/**
* Retrieving multiple configurations is not supported by AWS AppConfig.
*/
getMultiple(path: string, _options?: unknown): Promise<void>;
/**
* Retrieve a configuration from AWS AppConfig.
*
* First we start the session and after that we retrieve the configuration from AppSync.
* When starting a session, the service returns a token that can be used to poll for changes
* for up to 24hrs, so we cache it for later use together with the expiration date.
*
* The value of the configuration is also cached internally because AppConfig returns an empty
* value if the configuration has not changed since the last poll. This way even if your code
* polls the configuration multiple times, we return the most recent value by returning the cached
* one if an empty response is returned by AppConfig.
*
* @param {string} name - Name of the configuration or its ID
* @param {AppConfigGetOptions} options - SDK options to propagate to `StartConfigurationSession` API call
*/
protected _get(name: string, options?: AppConfigGetOptions): Promise<Uint8Array | undefined>;
/**
* Retrieving multiple configurations is not supported by AWS AppConfig.
*
* @throws Not Implemented Error.
*/
protected _getMultiple(_path: string, _sdkOptions?: unknown): Promise<Record<string, unknown> | undefined>;
}
export { AppConfigProvider };
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