AWS CDK Reference

Appearance

v2.274.0

StateMachineFragment ​

Base class for reusable state machine fragments.

Source
aws-stepfunctions/lib/state-machine-fragment.ts

Example ​

ts
import { Stack } from 'aws-cdk-lib';
import { Construct } from 'constructs';
import * as sfn from 'aws-cdk-lib/aws-stepfunctions';

interface MyJobProps {
  jobFlavor: string;
}

class MyJob extends sfn.StateMachineFragment {
  public readonly startState: sfn.State;
  public readonly endStates: sfn.INextable[];

  constructor(parent: Construct, id: string, props: MyJobProps) {
    super(parent, id);

    const choice = new sfn.Choice(this, 'Choice')
      .when(sfn.Condition.stringEquals('$.branch', 'left'), new sfn.Pass(this, 'Left Branch'))
      .when(sfn.Condition.stringEquals('$.branch', 'right'), new sfn.Pass(this, 'Right Branch'));

    // ...

    this.startState = choice;
    this.endStates = choice.afterwards().endStates;
  }
}

class MyStack extends Stack {
  constructor(scope: Construct, id: string) {
    super(scope, id);
    // Do 3 different variants of MyJob in parallel
    const parallel = new sfn.Parallel(this, 'All jobs')
      .branch(new MyJob(this, 'Quick', { jobFlavor: 'quick' }).prefixStates())
      .branch(new MyJob(this, 'Medium', { jobFlavor: 'medium' }).prefixStates())
      .branch(new MyJob(this, 'Slow', { jobFlavor: 'slow' }).prefixStates());

    new sfn.StateMachine(this, 'MyStateMachine', {
      definitionBody: sfn.DefinitionBody.fromChainable(parallel),
    });
  }
}

Initializer ​

ts
new StateMachineFragment(scope: Construct, id: string)
python
StateMachineFragment(scope: Construct, id: str)
java
new StateMachineFragment(Construct scope, String id)
csharp
new StateMachineFragment(Construct scope, string id)
go
NewStateMachineFragment(Scope Construct, Id *string)

Properties ​

endStatesINextable[]end_statestyping.List[INextable]endStatesList<INextable>EndStatesINextable[]EndStates*[]INextablerequired#
The states to chain onto if this fragment is used.
idstringidstridStringIdstringId*stringrequired#
Descriptive identifier for this chainable.
nodeNodenodeNodenodeNodeNodeNodeNodeNoderequired#
The tree node.
startStateStatestart_stateStatestartStateStateStartStateStateStartStateStaterequired#
The start state of this state machine fragment.

Methods ​

isConstruct(x: any): boolean@staticmethod def is_construct(x: Any) -> boolpublic static Boolean isConstruct(Object x)public static bool IsConstruct(object x)func IsConstruct(X interface{}) *boolstatic#
Checks if `x` is a construct.
notes · 1 parameter · returns

Use this method instead of instanceof to properly detect Construct instances, even when the construct library is symlinked.

Explanation: in JavaScript, multiple copies of the constructs library on disk are seen as independent, completely different libraries. As a consequence, the class Construct in each copy of the constructs library is seen as a different class, and an instance of one class will not test as instanceof the other class. npm install will not create installations like this, but users may manually symlink construct libraries together or use a monorepo tool: in those cases, multiple copies of the constructs library can be accidentally installed, and instanceof will behave unpredictably. It is safest to avoid using instanceof, and using this type-testing method instead.

Parameters

  • xxxxX — Any object.

Returns: true if x is an object created from a class which extends Construct.

prefixStates(prefix?: string): StateMachineFragment // chainabledef prefix_states(self, prefix: typing.Optional[str] = None) -> StateMachineFragmentpublic StateMachineFragment prefixStates(String prefix)public StateMachineFragment PrefixStates(string? prefix = null)func PrefixStates(Prefix *string) StateMachineFragment#
Prefix the IDs of all states in this state machine fragment.

Use this to avoid multiple copies of the state machine all having the same state IDs.

1 parameter

Parameters

  • prefixprefixprefixprefixPrefix — The prefix to add.
toSingleState(options?: SingleStateOptions): Paralleldef to_single_state(self, options: typing.Optional[SingleStateOptions] = None) -> Parallelpublic Parallel toSingleState(SingleStateOptions options)public Parallel ToSingleState(SingleStateOptions? options = null)func ToSingleState(Options SingleStateOptions) Parallel#
Wrap all states in this state machine fragment up into a single state.
notes

This can be used to add retry or error handling onto this state machine fragment.

Be aware that this changes the result of the inner state machine to be an array with the result of the state machine in it. Adjust your paths accordingly. For example, change 'outputPath' to '$[0]'.

toString(): stringdef to_string(self, ) -> strpublic String toString()public string ToString()func ToString() *string#
Returns a string representation of this construct.
with(...mixins: IMixin[]): IConstructdef with(self, mixins: IMixin) -> IConstructpublic IConstruct with(IMixin mixins)public IConstruct With(IMixin mixins)func With(Mixins IMixin) 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.

1 parameter · returns

Parameters

  • mixinsmixinsmixinsmixinsMixins — The mixins to apply.

Returns: This construct for chaining