Using Amazon States Language to define Step Functions workflows
The Amazon States Language is a JSON-based, structured language used to define your state machine, a
collection of states, that can do work (Task
states), determine which states to transition to next (Choice
states), stop an
execution with an error (Fail
states), and so on.
For more information, see the Amazon
States Language Specification
To create a state machine on the Step Functions console
Note
If you define your state machines outside the Step Functions' console, such as in an editor of your choice, you must save your state machine definitions with the extension .asl.json.
Example Amazon States Language Specification (JSONata)
{
"Comment": "An example of the Amazon States Language using a choice state.",
"QueryLanguage": "JSONata",
"StartAt": "FirstState",
"States": {
"FirstState": {
"Type": "Task",
"Assign":{"foo" : "{% $states.input.foo_input %}" }
"Resource": "arn:aws-cn:lambda:us-east-1:123456789012:function:FUNCTION_NAME
",
"Next": "ChoiceState"
},
"ChoiceState": {
"Type": "Choice",
"Default": "DefaultState",
"Choices": [
{
"Next": "FirstMatchState",
"Condition": "{% $foo = 1 %}"
},
{
"Next": "SecondMatchState",
"Condition": "{% $foo = 2 %}"
}
]
},
"FirstMatchState": {
"Type" : "Task",
"Resource": "arn:aws-cn:lambda:us-east-1:123456789012:function:OnFirstMatch
",
"Next": "NextState"
},
"SecondMatchState": {
"Type" : "Task",
"Resource": "arn:aws-cn:lambda:us-east-1:123456789012:function:OnSecondMatch
",
"Next": "NextState"
},
"DefaultState": {
"Type": "Fail",
"Error": "DefaultStateError",
"Cause": "No Matches!"
},
"NextState": {
"Type": "Task",
"Resource": "arn:aws-cn:lambda:us-east-1:123456789012:function:FUNCTION_NAME
",
"End": true
}
}
}