Pass workflow state - AWS Step Functions
Pass State Example (JSONPath)

Pass workflow state

Managing state and transforming data

Step Functions recently added variables and JSONata to manage state and transform data.

Learn about Passing data with variables and Transforming data with JSONata.

A Pass state ("Type": "Pass") passes its input to its output, without performing work. Pass states are useful when constructing and debugging state machines.

You can also use a Pass state to transform JSON state input using filters, and then pass the transformed data to the next state in your workflows. For information about input transformation, see Manipulate parameters in Step Functions workflows.

In addition to the common state fields, Pass states allow the following fields.

Assign (Optional, JSONata only)

A collection of key-value pairs to assign data to variables. For more information, see Passing data between states with variables.

Output (Optional, JSONata only)

Used to specify and transform output from the state. When specified, the value overrides the state output default.

The output field accepts any JSON value (object, array, string, number, boolean, null). Any string value, including those inside objects or arrays, will be evaluated as JSONata if surrounded by {% %} characters.

Output also accepts a JSONata expression directly, for example: "Output": "{% jsonata expression %}"

For more information, see Transforming data with JSONata in Step Functions.

Result (Optional, JSONPath only)

Refers to the output of a virtual task that is passed on to the next state. If you include the ResultPath field in your state machine definition, Result is placed as specified by ResultPath and passed on to the next state.

ResultPath (Optional, JSONPath only)

Specifies where to place the output (relative to the input) of the virtual task specified in Result. The input is further filtered as specified by the OutputPath field (if present) before being used as the state's output. For more information, see Processing input and output in Step Functions.

Parameters (Optional, JSONPath only)

Creates a collection of key-value pairs that will be passed as input. You can specify Parameters as a static value or select from the input using a path. For more information, see Manipulate parameters in Step Functions workflows.

Pass State Example (JSONPath)

Here is an example of a Pass state that injects some fixed data into the state machine, probably for testing purposes.

"No-op": {
  "Type": "Pass",
  "Result": {
    "x-datum": 0.381018,
    "y-datum": 622.2269926397355
  },
  "ResultPath": "$.coords",
  "End": true
}

Suppose the input to this state is the following.

{
  "georefOf": "Home"
}

Then the output would be this.

{
  "georefOf": "Home",
  "coords": {
    "x-datum": 0.381018,
    "y-datum": 622.2269926397355
  }
}