Pass workflow state
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 byResultPath
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 theOutputPath
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
}
}