Function getAppConfig

Example

import { getAppConfig } from '@aws-lambda-powertools/parameters/appconfig';

export const handler = async (): Promise<void> => {
  // Retrieve a configuration profile
  const encodedConfig = await getAppConfig('my-config', {
    application: 'my-app',
    environment: 'prod',
  });
  const config = new TextDecoder('utf-8').decode(encodedConfig);
};
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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

import { getAppConfig } from '@aws-lambda-powertools/parameters/appconfig';

export const handler = async (): Promise<void> => {
  // Retrieve a configuration profile and cache it for 10 seconds
  const encodedConfig = await getAppConfig('my-config', {
    application: 'my-app',
    environment: 'prod',
  });
  const config = new TextDecoder('utf-8').decode(encodedConfig);
};
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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

import { getAppConfig } from '@aws-lambda-powertools/parameters/appconfig';

export const handler = async (): Promise<void> => {
  // Retrieve a config and always fetch the latest value
  const config = await getAppConfig('my-config', {
    application: 'my-app',
    environment: 'prod',
    forceFetch: true,
  });
  const config = new TextDecoder('utf-8').decode(encodedConfig);
};
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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

import { getAppConfig } from '@aws-lambda-powertools/parameters/appconfig';

export const handler = async (): Promise<void> => {
  // Retrieve a JSON config or Feature Flag and parse it as JSON
  const config = await getAppConfig('my-config', {
    application: 'my-app',
    environment: 'prod',
    transform: 'json'
  });
};
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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

import { getAppConfig } from '@aws-lambda-powertools/parameters/appconfig';

export const handler = async (): Promise<void> => {
  // Retrieve a base64-encoded string and decode it
  const config = await getAppConfig('my-config', {
    application: 'my-app',
    environment: 'prod',
    transform: 'binary'
  });
};
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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

import { getAppConfig } from '@aws-lambda-powertools/parameters/appconfig';

export const handler = async (): Promise<void> => {
  // Retrieve a config and pass extra options to the AWS SDK v3 for JavaScript client
  const config = await getAppConfig('my-config', {
    application: 'my-app',
    environment: 'prod',
    sdkOptions: {
      RequiredMinimumPollIntervalInSeconds: 60,
    },
  });
  const config = new TextDecoder('utf-8').decode(encodedConfig);
};
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This object accepts the same options as the AWS SDK v3 for JavaScript AppConfigData client.

Built-in provider class

For greater flexibility such as configuring the underlying SDK client used by built-in providers, you can use the AppConfigProvider class.

For more usage examples, see our documentation.