How to interpret actionDataFilter when used in an action in a foreach state

[murat-shiftright]

Hello,

As the title suggests, I am not clear on what the expected behavior is when actionDataFilter parameter is used in an action in a foreach state. I could not find specific examples in either documentation or the discussions related to this so I would appreciate any help you could provide to clarify things for me.

First, let me paste a few definitions from the spec relevant to my questions here for convenience:

• The inputCollection parameter in a foreach state : Workflow expression selecting an array element of the states data
• The outputCollection parameter in a foreach state: Workflow expression specifying an array element of the states data to add the results of each iteration
• The fromStateData parameter in an actionDataFilter: Workflow expression that filters state data that can be used by the action
• The toStateData parameter in an actionDataFilter: Workflow expression that selects a state data element to which the action results should be added/merged into. If not specified denotes the top-level state data element

I have two questions on data handling, one on the input and one on the output side.

• On the input side, should the fromStateData be applied to the iteration parameter as if it were the state data or should iteration parameter be considered as a JQ expression variable that can be referenced and fromStateData should be applied to the state data as would be the case say in an operation type state?

• On the output side, what should happen if an action in a foreach state as an actionDataFilter property defined (assuming that actionDataFilter will not have useResults set to false)? Should the actionDataFilter.toStateData be ignored or should one view the iteration parameter as if it were the state data that an action would merge its output to?

Thanks,

Murat

[giorgosera]

I am also interested in this! We're trying to implement foreach and the things you mentioned (especially the output) related are not clear from the documentation.

I found this part of the code in Synapse (runtime implementation) which might hint to how this should be done.

[ricardozanini]

Hi! You can refer to the new DSL and how we handle "for each" at the moment: https://github.com/serverlessworkflow/specification/blob/main/dsl-reference.md#for.

The data handling is simpler now. I'm closing this discussion since it refers to an old spec version. If you still have questions or comments, please feel free to reopen it!