Class Chain

A collection of states to chain onto.

Inheritance

object

Chain

Implements

IChainable

Namespace: Amazon.CDK.AWS.StepFunctions

Assembly: Amazon.CDK.Lib.dll

Syntax (csharp)

public class Chain : DeputyBase, IChainable

Syntax (vb)

Public Class Chain Inherits DeputyBase Implements IChainable

Remarks

A Chain has a start and zero or more chainable ends. If there are zero ends, calling next() on the Chain will fail.

ExampleMetadata: infused

Examples

var map = new Map(this, "Map State", new MapProps {
                 MaxConcurrency = 1,
                 ItemsPath = JsonPath.StringAt("$.inputForMap"),
                 ItemSelector = new Dictionary<string, object> {
                     { "item", JsonPath.StringAt("$.Map.Item.Value") }
                 },
                 ResultPath = "$.mapOutput"
             });

             // The Map iterator can contain a IChainable, which can be an individual or multiple steps chained together.
             // Below example is with a Choice and Pass step
             var choice = new Choice(this, "Choice");
             var condition1 = Condition.StringEquals("$.item.status", "SUCCESS");
             var step1 = new Pass(this, "Step1");
             var step2 = new Pass(this, "Step2");
             var finish = new Pass(this, "Finish");

             var definition = choice.When(condition1, step1).Otherwise(step2).Afterwards().Next(finish);

             map.ItemProcessor(definition);

Synopsis

Properties

EndStates	The chainable end state(s) of this chain.
Id	Identify this Chain.
StartState	The start state of this chain.

Methods

Custom(State, INextable[], IChainable)	Make a Chain with specific start and end states, and a last-added Chainable.
Next(IChainable)	Continue normal execution with the given state.
Sequence(IChainable, IChainable)	Make a Chain with the start from one chain and the ends from another.
Start(IChainable)	Begin a new Chain from one chainable.
ToSingleState(string, IParallelProps?)	Return a single state that encompasses all states in the chain.

Properties

EndStates

The chainable end state(s) of this chain.

public virtual INextable[] EndStates { get; }

Property Value

INextable[]

Remarks

A Chain has a start and zero or more chainable ends. If there are zero ends, calling next() on the Chain will fail.

ExampleMetadata: infused

Id

Identify this Chain.

public virtual string Id { get; }

Property Value

string

Remarks

A Chain has a start and zero or more chainable ends. If there are zero ends, calling next() on the Chain will fail.

ExampleMetadata: infused

StartState

The start state of this chain.

public virtual State StartState { get; }

Property Value

State

Remarks

A Chain has a start and zero or more chainable ends. If there are zero ends, calling next() on the Chain will fail.

ExampleMetadata: infused

Methods

Custom(State, INextable[], IChainable)

Make a Chain with specific start and end states, and a last-added Chainable.

public static Chain Custom(State startState, INextable[] endStates, IChainable lastAdded)

Parameters

startState State

endStates INextable[]

lastAdded IChainable

Returns

Chain

Remarks

A Chain has a start and zero or more chainable ends. If there are zero ends, calling next() on the Chain will fail.

ExampleMetadata: infused

Next(IChainable)

Continue normal execution with the given state.

public virtual Chain Next(IChainable next)

Parameters

next IChainable

Returns

Chain

Remarks

A Chain has a start and zero or more chainable ends. If there are zero ends, calling next() on the Chain will fail.

ExampleMetadata: infused

Sequence(IChainable, IChainable)

Make a Chain with the start from one chain and the ends from another.

public static Chain Sequence(IChainable start, IChainable next)

Parameters

start IChainable

next IChainable

Returns

Chain

Remarks

A Chain has a start and zero or more chainable ends. If there are zero ends, calling next() on the Chain will fail.

ExampleMetadata: infused

Start(IChainable)

Begin a new Chain from one chainable.

public static Chain Start(IChainable state)

Parameters

state IChainable

Returns

Chain

Remarks

A Chain has a start and zero or more chainable ends. If there are zero ends, calling next() on the Chain will fail.

ExampleMetadata: infused

ToSingleState(string, IParallelProps?)

Return a single state that encompasses all states in the chain.

public virtual Parallel ToSingleState(string id, IParallelProps? props = null)

Parameters

id string

props IParallelProps

Returns

Parallel

Remarks

This can be used to add error handling to a sequence of states.

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]'.

Implements

IChainable