CustomFunctionGroup doesn't seem to work as a root object in an ldemengine configuration file, what should I do

[Steve Barber]

I've declared a CustomFunctionGroup as a root object in a LiveView Engine Configuration ( com.tibco.ep.ldm.configuration.ldmengine ) but I get a runtime error that a function declared there can't be found, even though StreamBase Studio doesn't give a typecheck error when invoking the same function. Also, the HOCON editor doesn't complain about the CustomFunctionGroup, either, indicating that CustomFunctionGroup is valid there.

 

What's going on here How should I be configuring CustomFunctionGroups in LiveView fragments

[Steve Barber]

This question came from a customer I've been working with, and thought the issue should be more widely known, as others have had the same question. So I'm asking and answering my own question, just to conform with the conventions of TIBCO Community Answers, if not exactly the spirit.

 

Anyway, it turns out that CustomFunctionGroup is not a valid root object in a LiveView Engine Configuration, even though maybe it feels like it should be. The HOCON editor probably should not accept it there.

 

It turns out that even in a LiveView fragment, a CustomFunctionGroup still must be declared in a StreamBase Engine Configuration, even though other root objects of the StreamBase Engine Configuration (such as, for example, StreamBaseEngine) wouldn't be acted upon in a LiveView fragment context.

 

The upside of this arguably a bit puzzling design is that the configuration files for custom functions may be reused as is between EventFlow Fragments and LiveView Fragments.

[Steve Barber]

Closely related, though not quite the same issue -- even if a CustomFunctionGroup exists in a StreamBase Engine configuration in a LiveView Fragment, that configuration isn't acted upon in TIBCO Streaming 10.5.0, which was the first version for CustomFunctionGroups.

 

However, starting in either 10.6.0 or 10.6.1 (I can't remember which and the change isn't documented and I'm not motivated to spend time figuring that out at the moment), LiveView fragments now successfully recognize CustomFunctionGroups in StreamBase Engine configurations.