NIFI:Json Content Parsing in FlowFile - json

Question

I have text attribute in GenerateFlowfile processor like this:
[{
"status": {
"runStatus": "STOPPED"
},
"component": {
"state": "STOPPED",
"id": "ea5db028-015d-1000-5ad5-80fd006dda92"
},
"revision": {
"version": 46,
"clientId": "ef592126-015d-1000-bf4f-93c7cf7eedc0"
}
} ]
and related groovy script in my ExecuteScript processor :
import org.apache.commons.io.IOUtils
import java.nio.charset.*
def flowFile = session.get();
if (flowFile == null) {
return;
}
def slurper = new groovy.json.JsonSlurper()
def attrs = [:] as Map<String,String>
session.read(flowFile,
{ inputStream ->
def text = IOUtils.toString(inputStream, StandardCharsets.UTF_8)
text=flowFile.getAttribute('text')
def obj = slurper.parseText(text)
obj.each {k,v ->
attrs[k] = v.toString()
}
} as InputStreamCallback)
flowFile = session.putAllAttributes(flowFile, attrs)
session.transfer(flowFile, REL_SUCCESS)
but my processor still shows me exception like this, what should i change?

Answer 1

the problem that the root element of your json is an array
and you try to iterate it like map .each{k,v-> ... }
probably you want to take the first map to iterate it like in code below
def obj=[ [a:1] ]
//this line will throw exception:
//obj.each{k,v-> println "$k->$v" }
//but this one not
obj[0].each{k,v-> println "$k->$v" }
fyi: there is a EvaluateJsonPath processor that could extract attributes from json flowfile content and put result into attribute