AWS SDK for JavaScript SFN Client for Node.js, Browser and React Native.
Step Functions
Step Functions is a service that lets you coordinate the components of distributed applications and microservices using visual workflows.
You can use Step Functions to build applications from individual components, each of which performs a discrete function, or task, allowing you to scale and change applications quickly. Step Functions provides a console that helps visualize the components of your application as a series of steps. Step Functions automatically triggers and tracks each step, and retries steps when there are errors, so your application executes predictably and in the right order every time. Step Functions logs the state of each step, so you can quickly diagnose and debug any issues.
Step Functions manages operations and underlying infrastructure to ensure your application is available at any scale. You can run tasks on Amazon Web Services, your own servers, or any system that has access to Amazon Web Services. You can access and use Step Functions using the console, the Amazon Web Services SDKs, or an HTTP API. For more information about Step Functions, see the Step Functions Developer Guide .
If you use the Step Functions API actions using Amazon Web Services SDK integrations, make sure the API actions are in camel case and parameter names are in Pascal case. For example, you could use Step Functions API action startSyncExecution and specify its parameter as StateMachineArn.
To install the this package, simply type add or install @aws-sdk/client-sfn using your favorite package manager:
npm install @aws-sdk/client-sfnyarn add @aws-sdk/client-sfnpnpm add @aws-sdk/client-sfn
The AWS SDK is modulized by clients and commands.
To send a request, you only need to import the SFNClient and
the commands you need, for example ListActivitiesCommand:
// ES5 example
const { SFNClient, ListActivitiesCommand } = require("@aws-sdk/client-sfn");// ES6+ example
import { SFNClient, ListActivitiesCommand } from "@aws-sdk/client-sfn";To send a request, you:
- Initiate client with configuration (e.g. credentials, region).
- Initiate command with input parameters.
- Call
sendoperation 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 SFNClient({ region: "REGION" });
const params = {
/** input parameters */
};
const command = new ListActivitiesCommand(params);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.
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.
});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.
});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-sfn";
const client = new AWS.SFN({ region: "REGION" });
// async/await.
try {
const data = await client.listActivities(params);
// process data.
} catch (error) {
// error handling.
}
// Promises.
client
.listActivities(params)
.then((data) => {
// process data.
})
.catch((error) => {
// error handling.
});
// callbacks.
client.listActivities(params, (err, data) => {
// process err and data.
});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;
* }
*/
}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 or API Reference.
- Check out the blog posts tagged with
aws-sdk-json AWS Developer Blog. - Ask a question on StackOverflow and tag it with
aws-sdk-js. - Join the AWS JavaScript community on gitter.
- If it turns out that you may have found a bug, please open an issue.
To test your universal JavaScript code in Node.js, browser and react-native environments, visit our code samples repo.
This client code is generated automatically. Any modifications will be overwritten the next time the @aws-sdk/client-sfn package is updated.
To contribute to client you can check our generate clients scripts.
This SDK is distributed under the Apache License, Version 2.0, see LICENSE for more information.