I am creating a stage that has an input parameter. I want to be able to have usage of the stage either take a specific value or to specify to use the contents of a variable. Is this done in the stage source, and if so how?
It’s up to the stage to parse the value of its config property and decide whether to take that as a raw value or as a reference to another field.
There is a helper method in the SDK that handles $ expressions. See DocumentUtil#evaluateTemplate.
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