Hi Rohit, You're using the following expression: ${myJson:jsonPath('$.stud_id')} So it assumes that in your incoming flow files you have an attribute called 'myJson' that contains your JSON document from which you will extract the value of the key stud_id. If the JSON is in the content of your flow file (not as an attribute), then you first need to use an EvaluateJsonPath to extract the value of the key stud_id as an attribute of your flow file, and you will be able to use this attribute for your document ID property in the Couchbase processor. Does it maje sense?
Thanks, Pierre 2018-03-13 11:31 GMT+01:00 Rohit <rsvang...@gmail.com>: > Hi, > > I am trying to create couchbase document_id (PutCouchbaseKey processor) as > json key "stud_id" using expression-language but i am getting below error. > > due to uncaught > Exception:org.apache.nifi.attribute.expressac_noguage.exception. > AttributeExpressionLanguageException:Subject > is empty. > > Keys:- > {stud_id,first_name,last_name} > > My Teamplate:- > > ExecuteHQL->SplitAvro->AvroToJson->PutCouch > > > nifi1.PNG > <http://apache-nifi-developer-list.39713.n7.nabble.com/file/t927/nifi1.PNG > > > > > > -- > Sent from: http://apache-nifi-developer-list.39713.n7.nabble.com/ >