This is an example found at https://github.com/apache/nifi/blob/master/nifi-nar-bundles/nifi-scripting-bundle/nifi-scripting-processors/src/test/resources/jython/test_update_attribute.py . It shows how to set up InvokeScriptedProcessor for python (jython) to add a simple attribute to a flowfile.
How would I integrate in this structure a call to PyStreamCallback() that allows me to replace the *contents* of the flowfile? Typically PyStreamCallback() to accomplish this is its own class, but here it looks like I would need to make it a method in the UpdateAttributes() class. I've been unable to get that to work. Thank you in advance for any help. #! /usr/bin/python # # Licensed to the Apache Software Foundation (ASF) under one # or more contributor license agreements. See the NOTICE file # distributed with this work for additional information # regarding copyright ownership. The ASF licenses this file # to you under the Apache License, Version 2.0 (the # "License"); you may not use this file except in compliance # with the License. You may obtain a copy of the License at # # http://www.apache.org/licenses/LICENSE-2.0 # # Unless required by applicable law or agreed to in writing, # software distributed under the License is distributed on an # "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY # KIND, either express or implied. See the License for the # specific language governing permissions and limitations # under the License. # import sys import traceback from org.apache.nifi.processor import Processor from org.apache.nifi.processor import Relationship from org.apache.nifi.components import PropertyDescriptor from org.apache.nifi.processor.util import StandardValidators class UpdateAttributes(Processor) : __rel_success = Relationship.Builder().description("Success").name("success" ).build() def __init__(self) : pass def initialize(self, context) : pass def getRelationships(self) : return set([self.__rel_success]) def validate(self, context) : pass def getPropertyDescriptors(self) : descriptor = PropertyDescriptor.Builder().name("for-attributes" ).addValidator(StandardValidators.NON_EMPTY_VALIDATOR).build() return [descriptor] def onPropertyModified(self, descriptor, newValue, oldValue) : pass def onTrigger(self, context, sessionFactory) : session = sessionFactory.createSession() try : # ensure there is work to do flowfile = session.get() if flowfile is None : return # extract some attribute values fromPropertyValue = context.getProperty("for-attributes").getValue() fromAttributeValue = flowfile.getAttribute("for-attributes") # set an attribute flowfile = session.putAttribute(flowfile, "from-property", fromPropertyValue) flowfile = session.putAttribute(flowfile, "from-attribute", fromAttributeValue) # transfer session.transfer(flowfile, self.__rel_success) session.commit() except : print sys.exc_info()[0] print "Exception in TestReader:" print '-' * 60 traceback.print_exc(file=sys.stdout) print '-' * 60 session.rollback(true) raise processor = UpdateAttributes()
