# @aws-sdk/client-appconfigdata
## 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.
This token should only be used once in your first call to
GetLatestConfiguration. You must use the new token
in the GetLatestConfiguration response
(NextPollConfigurationToken) in each subsequent call to
GetLatestConfiguration.
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.
The InitialConfigurationToken and
NextPollConfigurationToken should only be used once. To support long poll
use cases, the tokens are valid for up to 24 hours. If a
GetLatestConfiguration call uses an expired token, the system returns
BadRequestException.
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 Retrieving 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`:
```js
// ES5 example
const { AppConfigDataClient, GetLatestConfigurationCommand } = require("@aws-sdk/client-appconfigdata");
```
```ts
// 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.
```js
// 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](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/await)
operator to wait for the promise returned by send operation as follows:
```js
// 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](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Using_promises#chaining)
to execute send operation.
```js
client.send(command).then(
(data) => {
// process data.
},
(error) => {
// error handling.
}
);
```
Promises can also be called using `.catch()` and `.finally()` as follows:
```js
client
.send(command)
.then((data) => {
// process data.
})
.catch((error) => {
// error handling.
})
.finally(() => {
// finally.
});
```
#### Callbacks
We do not recommend using callbacks because of [callback hell](http://callbackhell.com/),
but they are supported by the send operation.
```js
// 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](https://aws.amazon.com/blogs/developer/modular-packages-in-aws-sdk-for-javascript/)
```ts
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).
```js
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.
- Visit [Developer Guide](https://docs.aws.amazon.com/sdk-for-javascript/v3/developer-guide/welcome.html)
or [API Reference](https://docs.aws.amazon.com/AWSJavaScriptSDK/v3/latest/index.html).
- Check out the blog posts tagged with [`aws-sdk-js`](https://aws.amazon.com/blogs/developer/tag/aws-sdk-js/)
on AWS Developer Blog.
- Ask a question on [StackOverflow](https://stackoverflow.com/questions/tagged/aws-sdk-js) and tag it with `aws-sdk-js`.
- Join the AWS JavaScript community on [gitter](https://gitter.im/aws/aws-sdk-js-v3).
- If it turns out that you may have found a bug, please [open an issue](https://github.com/aws/aws-sdk-js-v3/issues/new/choose).
To test your universal JavaScript code in Node.js, browser and react-native environments,
visit our [code samples repo](https://github.com/aws-samples/aws-sdk-js-tests).
## 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](https://github.com/aws/aws-sdk-js-v3/tree/main/scripts/generate-clients).
## License
This SDK is distributed under the
[Apache License, Version 2.0](http://www.apache.org/licenses/LICENSE-2.0),
see LICENSE for more information.
## Client Commands (Operations List)
GetLatestConfiguration
[Command API Reference](https://docs.aws.amazon.com/AWSJavaScriptSDK/v3/latest/clients/client-appconfigdata/classes/getlatestconfigurationcommand.html) / [Input](https://docs.aws.amazon.com/AWSJavaScriptSDK/v3/latest/clients/client-appconfigdata/interfaces/getlatestconfigurationcommandinput.html) / [Output](https://docs.aws.amazon.com/AWSJavaScriptSDK/v3/latest/clients/client-appconfigdata/interfaces/getlatestconfigurationcommandoutput.html)
StartConfigurationSession
[Command API Reference](https://docs.aws.amazon.com/AWSJavaScriptSDK/v3/latest/clients/client-appconfigdata/classes/startconfigurationsessioncommand.html) / [Input](https://docs.aws.amazon.com/AWSJavaScriptSDK/v3/latest/clients/client-appconfigdata/interfaces/startconfigurationsessioncommandinput.html) / [Output](https://docs.aws.amazon.com/AWSJavaScriptSDK/v3/latest/clients/client-appconfigdata/interfaces/startconfigurationsessioncommandoutput.html)