Hi, I am having a requirement where user need to use execute script processor with python language to get the summation of all values from content file and summation result should add as new attribute to flow file, I am able to get the sum, But i am not getting how to pass newly created attribute to session for posting the attribute. Below is my code snippet. import traceback from org.apache.nifi.processors.script import ExecuteScript from org.apache.nifi.processor.io import StreamCallback from java.io import BufferedReader, InputStreamReader, OutputStreamWriter class ConvertFiles(StreamCallback) : def __init__(self) : pass def process(self, inputStream, outputStream) : try : reader = InputStreamReader(inputStream,"UTF-8") bufferedReader = BufferedReader(reader) writer = OutputStreamWriter(outputStream,"UTF-8") line = bufferedReader.readLine() while line != None: total = 0 ChangedRec = line.upper() writer.write(ChangedRec) writer.write('\n') a=line.split(",") for valu in a: b=valu.strip() total += int(b) line = bufferedReader.readLine() print("Summation of Records are %s ",total) writer.flush() writer.close() reader.close() bufferedReader.close() except : print "Exception in Reader:" print '-' * 60 traceback.print_exc(file=sys.stdout) print '-' * 60 raise session.transfer(flowFile, ExecuteScript.REL_FAILURE) finally : if bufferedReader is not None : bufferedReader.close() if reader is not None : reader.close() flowFile = session.get() if flowFile is not None : ConvertFilesData = ConvertFiles() session.write(flowFile, ConvertFilesData) flowFile = session.putAttribute(flowFile, "FileSum",ConvertFilesData.total) session.transfer(flowFile, ExecuteScript.REL_SUCCESS) Now I should get Total as value and attribute name as SumResult, Could you please help me to get the issue resolved. ... View more