@aws-sdk/client-sfn
Advanced tools
AWS SDK for JavaScript Sfn Client for Node.js, Browser and React Native
@aws-sdk/client-sfn is an AWS SDK for JavaScript package that allows developers to interact with AWS Step Functions. AWS Step Functions is a service that lets you coordinate multiple AWS services into serverless workflows, making it easier to build and manage complex applications.
Create State Machine
This feature allows you to create a new state machine in AWS Step Functions. The code sample demonstrates how to define a simple state machine and create it using the AWS SDK.
const { SFNClient, CreateStateMachineCommand } = require('@aws-sdk/client-sfn');
const client = new SFNClient({ region: 'us-west-2' });
const params = {
name: 'MyStateMachine',
definition: JSON.stringify({
Comment: 'A Hello World example of the Amazon States Language using a Pass state',
StartAt: 'HelloWorld',
States: {
HelloWorld: {
Type: 'Pass',
Result: 'Hello, World!',
End: true
}
}
}),
roleArn: 'arn:aws:iam::123456789012:role/service-role/MyRole'
};
const run = async () => {
try {
const data = await client.send(new CreateStateMachineCommand(params));
console.log('State Machine ARN:', data.stateMachineArn);
} catch (err) {
console.error(err);
}
};
run();Start Execution
This feature allows you to start an execution of a state machine. The code sample demonstrates how to start an execution with input parameters.
const { SFNClient, StartExecutionCommand } = require('@aws-sdk/client-sfn');
const client = new SFNClient({ region: 'us-west-2' });
const params = {
stateMachineArn: 'arn:aws:states:us-west-2:123456789012:stateMachine:MyStateMachine',
input: JSON.stringify({
key1: 'value1',
key2: 'value2'
})
};
const run = async () => {
try {
const data = await client.send(new StartExecutionCommand(params));
console.log('Execution ARN:', data.executionArn);
} catch (err) {
console.error(err);
}
};
run();Describe Execution
This feature allows you to describe an execution of a state machine. The code sample demonstrates how to retrieve details of a specific execution.
const { SFNClient, DescribeExecutionCommand } = require('@aws-sdk/client-sfn');
const client = new SFNClient({ region: 'us-west-2' });
const params = {
executionArn: 'arn:aws:states:us-west-2:123456789012:execution:MyStateMachine:MyExecution'
};
const run = async () => {
try {
const data = await client.send(new DescribeExecutionCommand(params));
console.log('Execution Details:', data);
} catch (err) {
console.error(err);
}
};
run();The 'aws-sdk' package is the official AWS SDK for JavaScript, which includes support for all AWS services, including Step Functions. It is a more comprehensive package compared to @aws-sdk/client-sfn, which is specialized for Step Functions.
The 'serverless-step-functions' package is a Serverless Framework plugin that simplifies the deployment and management of AWS Step Functions. It provides a higher-level abstraction compared to @aws-sdk/client-sfn, making it easier to define and deploy state machines using the Serverless Framework.
AWS SDK for JavaScript SFN Client for Node.js, Browser and React Native.
AWS Step Functions
AWS 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 AWS, your own servers, or any system that has access to AWS. You can access and use Step Functions using the console, the AWS SDKs, or an HTTP API. For more information about Step Functions, see the AWS Step Functions Developer Guide .
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-sfnThe 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 CreateActivityCommand:
// ES5 example
const { SFNClient, CreateActivityCommand } = require("@aws-sdk/client-sfn");
// ES6+ example
import { SFNClient, CreateActivityCommand } from "@aws-sdk/client-sfn";
To send a request, you:
send operation on client with command object as input.destroy() to close open connections.// a client can be shared by difference commands.
const client = new SFNClient({ region: "REGION" });
const params = {
/** input parameters */
};
const command = new CreateActivityCommand(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) => {
// proccess 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.createActivity(params);
// process data.
} catch (error) {
// error handling.
}
// Promises.
client
.createActivity(params)
.then((data) => {
// process data.
})
.catch((error) => {
// error handling.
});
// callbacks.
client.createActivity(params, (err, data) => {
// proccess 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.
aws-sdk-js
on AWS Developer Blog.aws-sdk-js.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.
FAQs
AWS SDK for JavaScript Sfn Client for Node.js, Browser and React Native
The npm package @aws-sdk/client-sfn receives a total of 1,795,537 weekly downloads. As such, @aws-sdk/client-sfn popularity was classified as popular.
We found that @aws-sdk/client-sfn demonstrated a healthy version release cadence and project activity because the last version was released less than a year ago. It has 5 open source maintainers collaborating on the project.
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