nifi FlowFile has not been closed (Groovy script)warning

Question

new to nifi terminologies and flowfile handling.

Found a convenient way to handle incoming xml and parse it using XmlSlurper, but getting a warning for the below GroovyScript for incoming flowfiles-

the flow:

processor details:

script body:

def flowFile = session.get()
if(!flowFile) return
InputStream i = flowFile.read()
new XmlSlurper().parse(i)
i.close()
REL_SUCCESS << flowFile

Seems like issue with handling the flowfile. Can someone explain what exactly is happening here and how to best handle it? seems like this is causing the cluster to hang at times

Answer 1

use try-catch or withStream to close stream even if error occured:

def flowFile = session.get()
if(!flowFile) return
def xml = flowFile.read().withStream{i->
    new XmlSlurper().parse(i)
}
REL_SUCCESS << flowFile