Specification and Using multiple Data filters section: Error in Workflow definition ?

[radtriste]

https://github.com/serverlessworkflow/specification/blob/v0.8/specification.md#using-multiple-data-filters (same on main)

Event action is calling greeint function:

                "actions":[
                    {
                        "functionRef": {
                            "refName": "greetingFunction",
                            "arguments": {
                                "greeting": "${ .spanish } ",
                                "customerName": "${ .customerInfo.name } "
                            }
                        },
                        "actionDataFilter": {
                            "fromStateData": "${ .hello }",
                            "results": "${ .greetingMessageResult }",
                            "toStateData": "${ .finalCustomerGreeting }"
                        }
                    }
                ]

We have the action data filter using the "fromStateData": "${ .hello }",
which means the data for the action is

{
    "english": "Hello",
    "spanish": "Hola",
    "german": "Hallo",
    "russian": "Здравствуйте"
}

How is that possible that we use the customerInfo data into the function arguments, whereas, AFAIU, it is not in the current data for the action ?

[ricardozanini]

Yeah, it sounds like a bug. In the writing, it is stated:

(3) Event state performs its actions: Before the first action is executed, its actionDataFilter is invoked. Its "fromStateData" expression filters the current state data to select from its data that should be available to action arguments. In this example it selects the "hello" property from the current state data. At this point the action is executed. We assume that for this example "greetingFunction" returns:

And the action arguments are expecting customerInfo property. So it should be corrected as:

{
   "actions":[
      {
         "functionRef":{
            "refName":"greetingFunction",
            "arguments":{
               "greeting":"${ .hello.spanish } ",
               "customerName":"${ .customerInfo.name } "
            }
         },
         "actionDataFilter":{
            "fromStateData":"${ { hello, customerInfo } }",
            "results":"${ .greetingMessageResult }",
            "toStateData":"${ .finalCustomerGreeting }"
         }
      }
   ]
}

additional brackets added for GH formmating

[radtriste]

I will provide a PR then for the fix

I saw also some other small issues in the doc that I will correct in the same PR, if you are ok with that>

[tsurdilo]

@radtriste @ricardozanini

    "fromStateData":"${ { hello, customer } }", 

I think this should be ${ { hello, customerInfo } } as the event payload would be applied to state data first

But then this would be the same thing as the current state data when action filter is applied, so think just remove fromStateData in the action filter is better in this case

[ricardozanini]

@tsurdilo

think just remove fromStateData in the action filter is better in this case

Not necessarily. I think the filter example is fine, and the fromStateData action filter segregates the language from the hello attribute. It's not the most complex and smart example but it will do. :)