Mark Payne created NIFI-7572:
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Summary: Add a ScriptedTransformRecord processor
Key: NIFI-7572
URL: https://issues.apache.org/jira/browse/NIFI-7572
Project: Apache NiFi
Issue Type: New Feature
Components: Extensions
Reporter: Mark Payne
NiFi has started to put a heavier emphasis on Record-oriented processors, as
they provide many benefits including better performance and a better UX over
their purely byte-oriented counterparts. It is common to see users wanting to
transform a Record in some very specific way, but NiFi doesn't make this as
easy as it should. There are methods using ExecuteScript,
InvokedScriptedProcessor, ScriptedRecordWriter, and ScriptedRecordReader for
instance.
But each of these requires that the Script writer understand a lot about NiFi
and how to expose properties, create Property Descriptors, etc. and for fairly
simple transformation we end up with scripts where the logic takes fewer lines
of code than the boilerplate.
We should expose a Processor that allows a user to write a script that takes a
Record and transforms that Record in some way. The processor should be
configured with the following:
* Record Reader (required)
* Record Writer (required)
* Script Language (required)
* Script Body or Script File (one and only one of these required)
The script should implement a single method along the lines of:
{code:java}
void transform(Record record) throws Exception; {code}
The processor should have two relationships: "success" and "failure."
The script should not be allowed to expose any properties ore define any
relationships. The point is to keep the script focused purely on processing the
record itself.
It's not entirely clear to me how easy the Record API works with some of the
scripting languages. The Record object does expose a method named toMap() that
returns a Map<String, Object> containing the underlying key/value pairs.
However, the values in that Map may themselves be Records. It might make sense
to expose a new method toNormalizedMap() or something along those lines that
would return a Map<String, Object> where the values have been recursively
normalized, in much the same way that we do for JoltTransformRecord. This would
perhaps allow for cleaner syntax, but I'm not a scripting expert so I can't say
for sure whether such a method is necessary.
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