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AppConfigData Client - AWS SDK for JavaScript v3

@aws-sdk/client-appconfigdata

NPM version NPM downloads

Description

AWS SDK for JavaScript AppConfigData Client for Node.js, Browser and React Native.

AppConfig Data provides the data plane APIs your application uses to retrieve configuration data. Here's how it works:

Your application retrieves configuration data by first establishing a configuration session using the AppConfig Data StartConfigurationSession API action. Your session's client then makes periodic calls to GetLatestConfiguration to check for and retrieve the latest data available.

When calling StartConfigurationSession, your code sends the following information:

  • Identifiers (ID or name) of an AppConfig application, environment, and configuration profile that the session tracks.

  • (Optional) The minimum amount of time the session's client must wait between calls to GetLatestConfiguration.

In response, AppConfig provides an InitialConfigurationToken to be given to the session's client and used the first time it calls GetLatestConfiguration for that session.

When calling GetLatestConfiguration, your client code sends the most recent ConfigurationToken value it has and receives in response:

  • NextPollConfigurationToken: the ConfigurationToken value to use on the next call to GetLatestConfiguration.

  • NextPollIntervalInSeconds: the duration the client should wait before making its next call to GetLatestConfiguration. This duration may vary over the course of the session, so it should be used instead of the value sent on the StartConfigurationSession call.

  • The configuration: the latest data intended for the session. This may be empty if the client already has the latest version of the configuration.

For more information and to view example CLI commands that show how to retrieve a configuration using the AppConfig Data StartConfigurationSession and GetLatestConfiguration API actions, see Receiving the configuration in the AppConfig User Guide.

Installing

To install the this package, simply type add or install @aws-sdk/client-appconfigdata using your favorite package manager:

  • npm install @aws-sdk/client-appconfigdata
  • yarn add @aws-sdk/client-appconfigdata
  • pnpm add @aws-sdk/client-appconfigdata

Getting Started

Import

The AWS SDK is modulized by clients and commands. To send a request, you only need to import the AppConfigDataClient and the commands you need, for example GetLatestConfigurationCommand:

// ES5 example
const { AppConfigDataClient, GetLatestConfigurationCommand } = require("@aws-sdk/client-appconfigdata");
// ES6+ example
import { AppConfigDataClient, GetLatestConfigurationCommand } from "@aws-sdk/client-appconfigdata";

Usage

To send a request, you:

  • Initiate client with configuration (e.g. credentials, region).
  • Initiate command with input parameters.
  • Call send operation on client with command object as input.
  • If you are using a custom http handler, you may call destroy() to close open connections.
// a client can be shared by different commands.
const client = new AppConfigDataClient({ region: "REGION" });

const params = {
  /** input parameters */
};
const command = new GetLatestConfigurationCommand(params);

Async/await

We recommend using await operator to wait for the promise returned by send operation as follows:

// async/await.
try {
  const data = await client.send(command);
  // process data.
} catch (error) {
  // error handling.
} finally {
  // finally.
}

Async-await is clean, concise, intuitive, easy to debug and has better error handling as compared to using Promise chains or callbacks.

Promises

You can also use Promise chaining to execute send operation.

client.send(command).then(
  (data) => {
    // process data.
  },
  (error) => {
    // error handling.
  }
);

Promises can also be called using .catch() and .finally() as follows:

client
  .send(command)
  .then((data) => {
    // process data.
  })
  .catch((error) => {
    // error handling.
  })
  .finally(() => {
    // finally.
  });

Callbacks

We do not recommend using callbacks because of callback hell, but they are supported by the send operation.

// callbacks.
client.send(command, (err, data) => {
  // process err and data.
});

v2 compatible style

The client can also send requests using v2 compatible style. However, it results in a bigger bundle size and may be dropped in next major version. More details in the blog post on modular packages in AWS SDK for JavaScript

import * as AWS from "@aws-sdk/client-appconfigdata";
const client = new AWS.AppConfigData({ region: "REGION" });

// async/await.
try {
  const data = await client.getLatestConfiguration(params);
  // process data.
} catch (error) {
  // error handling.
}

// Promises.
client
  .getLatestConfiguration(params)
  .then((data) => {
    // process data.
  })
  .catch((error) => {
    // error handling.
  });

// callbacks.
client.getLatestConfiguration(params, (err, data) => {
  // process err and data.
});

Troubleshooting

When the service returns an exception, the error will include the exception information, as well as response metadata (e.g. request id).

try {
  const data = await client.send(command);
  // process data.
} catch (error) {
  const { requestId, cfId, extendedRequestId } = error.$$metadata;
  console.log({ requestId, cfId, extendedRequestId });
  /**
   * The keys within exceptions are also parsed.
   * You can access them by specifying exception names:
   * if (error.name === 'SomeServiceException') {
   *     const value = error.specialKeyInException;
   * }
   */
}

Getting Help

Please use these community resources for getting help. We use the GitHub issues for tracking bugs and feature requests, but have limited bandwidth to address them.

To test your universal JavaScript code in Node.js, browser and react-native environments, visit our code samples repo.

Contributing

This client code is generated automatically. Any modifications will be overwritten the next time the @aws-sdk/client-appconfigdata package is updated. To contribute to client you can check our generate clients scripts.

License

This SDK is distributed under the Apache License, Version 2.0, see LICENSE for more information.