The ApplyTemplate processor is fairly straightforward: it reads a mustache template from a provided path on disk and maps flowfile attributes to template values.
Dynamic properties (
MINIFI-171) would go a long way towards making these templates more flexible by using the union of input flowfile attributes and (possibly evaluated?) properties as the value map.
Due to its dependency on bustache and boost, it has been made into an optional extension, much like the libarchive processors have.
It may also be desirable to load the template from the input flowfile's contents instead of a configurable path.