class CustomState (construct)

Language	Type name
.NET	Amazon.CDK.AWS.StepFunctions.CustomState
Go	github.com/aws/aws-cdk-go/awscdk/v2/awsstepfunctions#CustomState
Java	software.amazon.awscdk.services.stepfunctions.CustomState
Python	aws_cdk.aws_stepfunctions.CustomState
TypeScript (source)	aws-cdk-lib » aws_stepfunctions » CustomState

Implements IConstruct, IDependable, IChainable, INextable

State defined by supplying Amazon States Language (ASL) in the state machine.

Example

import * as dynamodb from 'aws-cdk-lib/aws-dynamodb';

// create a table
const table = new dynamodb.Table(this, 'montable', {
  partitionKey: {
    name: 'id',
    type: dynamodb.AttributeType.STRING,
  },
});

const finalStatus = new sfn.Pass(this, 'final step');

// States language JSON to put an item into DynamoDB
// snippet generated from https://docs.aws.amazon.com/step-functions/latest/dg/tutorial-code-snippet.html#tutorial-code-snippet-1
const stateJson = {
  Type: 'Task',
  Resource: 'arn:aws:states:::dynamodb:putItem',
  Parameters: {
    TableName: table.tableName,
    Item: {
      id: {
        S: 'MyEntry',
      },
    },
  },
  ResultPath: null,
};

// custom state which represents a task to insert data into DynamoDB
const custom = new sfn.CustomState(this, 'my custom task', {
  stateJson,
});

// catch errors with addCatch
const errorHandler = new sfn.Pass(this, 'handle failure');
custom.addCatch(errorHandler);

// retry the task if something goes wrong
custom.addRetry({
  errors: [sfn.Errors.ALL],
  interval: Duration.seconds(10),
  maxAttempts: 5,
});

const chain = sfn.Chain.start(custom)
  .next(finalStatus);

const sm = new sfn.StateMachine(this, 'StateMachine', {
  definitionBody: sfn.DefinitionBody.fromChainable(chain),
  timeout: Duration.seconds(30),
  comment: 'a super cool state machine',
});

// don't forget permissions. You need to assign them
table.grantWriteData(sm);

Initializer

new CustomState(scope: Construct, id: string, props: CustomStateProps)

Parameters

• scope Construct
• id string — Descriptive identifier for this chainable.
• props CustomStateProps

Construct Props

Name	Type	Description
stateJson	{ [string]: any }	Amazon States Language (JSON-based) definition of the state.

---

stateJson

Type: { [string]: any }

Amazon States Language (JSON-based) definition of the state.

See also: https://docs.aws.amazon.com/step-functions/latest/dg/concepts-amazon-states-language.html

Properties

Name	Type	Description
endStates	INextable[]	Continuable states of this Chainable.
id	string	Descriptive identifier for this chainable.
node	Node	The tree node.
startState	State	First state of this Chainable.
stateId	string	Tokenized string that evaluates to the state's ID.

---

endStates

Type: INextable[]

Continuable states of this Chainable.

---

id

Type: string

Descriptive identifier for this chainable.

---

node

Type: Node

The tree node.

---

startState

Type: State

First state of this Chainable.

---

stateId

Type: string

Tokenized string that evaluates to the state's ID.

Methods

Name	Description
addCatch(handler, props?)	Add a recovery handler for this state.
addPrefix(x)	Add a prefix to the stateId of this state.
addRetry(props?)	Add retry configuration for this state.
bindToGraph(graph)	Register this state as part of the given graph.
next(next)	Continue normal execution with the given state.
toStateJson(queryLanguage?)	Returns the Amazon States Language object for this state.
toString()	Returns a string representation of this construct.
with(...mixins)	Applies one or more mixins to this construct.

---

addCatch(handler, props?)

public addCatch(handler: IChainable, props?: CatchProps): CustomState

Parameters

• handler IChainable
• props CatchProps

Returns

• CustomState

Add a recovery handler for this state.

When a particular error occurs, execution will continue at the error handler instead of failing the state machine execution.

---

addPrefix(x)

public addPrefix(x: string): void

Parameters

• x string

Add a prefix to the stateId of this state.

---

addRetry(props?)

public addRetry(props?: RetryProps): CustomState

Parameters

• props RetryProps

Returns

• CustomState

Add retry configuration for this state.

This controls if and how the execution will be retried if a particular error occurs.

---

bindToGraph(graph)

public bindToGraph(graph: StateGraph): void

Parameters

• graph StateGraph

Register this state as part of the given graph.

Don't call this. It will be called automatically when you work with states normally.

---

next(next)

public next(next: IChainable): Chain

Parameters

• next IChainable

Returns

• Chain

Continue normal execution with the given state.

---

toStateJson(queryLanguage?)

public toStateJson(queryLanguage?: QueryLanguage): json

Parameters

• queryLanguage QueryLanguage

Returns

• json

Returns the Amazon States Language object for this state.

---

toString()

public toString(): string

Returns

• string

Returns a string representation of this construct.

---

with(...mixins)

public with(...mixins: IMixin[]): IConstruct

Parameters

• mixins IMixin — The mixins to apply.

Returns

• IConstruct

Applies one or more mixins to this construct.

Mixins are applied in order. The list of constructs is captured at the start of the call, so constructs added by a mixin will not be visited. Use multiple with() calls if subsequent mixins should apply to added constructs.