@girish6    By xml file, I am assuming you are referring to the flow.xml.gz file? NiFi will only read the flow.xml.gz file during NiFi startup.  While NiFi is running the flow.xml resides completely in JVM heap memory and updates made via the UI or rest-api calls are pushed to flow.xml.gz only. It can be very dangerous manually editing the flow.xml.gz file and is not recommended.  Your queued FlowFiles are tightly coupled  to specific connection uuids.  While the NiFI UI/rest-api would block you from removing a connection which has queued FlowFiles, the flow.xml.gz would not offer such protections.  This could result in data loss if someone where to manually edit the flow.xml.gz file and restart NiFi.   Also keep in mind that in a multi-node NiFi cluster each node runs with its own copy of the flow.xml.gz loaded in to memory and the UI and rest-api calls are replicated to all nodes to make sure these files stay synced across your cluster.   Hope this helps, Matt ... View more

@fowler7878    No problem.  At this point you have extracted the the count successfully and used updateAttribute processor to subtract 31 from it.  You do not need to write it back to the content to use it in putEmail processor.   The majority of the putEmail processor configuration properties support NiFi Expression Language also. You can retrieve the value of your FlowFiiles attribute with this simple NiFi EL statement: ${COUNTFILES} So you can use above anywhere in the string you configure in the the "Subject" and/or "Message" configuration properties. Thanks, Matt If you found my answer help you to a solution, please don't forget to mark it as the accepted solution. ... View more

@xpelive    Just want to make sure a couple configurations. 1. The port you are using in the URL (8180) is the "nifi.web.http.port=" and not the "nifi.remote.input.socket.port=" port configured in your nifi.properties file. 2. When you start your NiFi instance, you will see a line output in the nifi-app.log when startup is complete that says the NiFi Ui is available at the following URLs:  Is "localhost:8180" listed in one of those URLs?  If not, you need to use one of the URLs listed in your Remote Process Group.  It might be that localhost is bound to a different NIC on your server than what NiFi is listening on. 3. If you have or will ever have more than 1 NiFi node in a NiFi cluster, using "localhost" is not going to work.  Your NiFi nodes should be configured to use the actual hostnames fo the server on which the service is running.  That hostname should be configured in both these properties: --- nifi.remote.input.host= --- nifi.web.http.host=   4. Since your NiFi is not secured, make sure that your nifi.properties file is not configured to be secure: nifi.remote.input.secure=false.     Null exceptions are particularly difficult to diagnose because a null basically means there was no error handling coded to handle to particular exception.  Thus we need o look at all angles of the configuration to see where the issue may reside. ... View more

@craignelson7007    Since you are starting with JSON content which you are extracting bits of into FlowFileAttributes just to write them back to json, have you considered skipping this completely and just using the NiFi JoltTransformJson processor to modify the existing json content instead? Here is a article with more details on using the JoltTransformJson processor: https://community.cloudera.com/t5/Community-Articles/Jolt-quick-reference-for-Nifi-Jolt-Processors/ta-p/244350   Otherwise: NiFi stores all FlowFile attributes as strings. The json you have written out in a FlowFile Attribute is going to be stored as a string in the attribute key  vckey_list = ["test value"]   The AttributesToJson processor builds a flat json from those attribute strings, so it is going to wrap the entire json in quotes and escape the embedded quotes within that string with a backslash.   You could use a couple replaceText processors after your AttributesToJson processor to remove the unwanted quotes and backslashes from the newly created content.   Here is another reference around this processor limitation: http://apache-nifi.1125220.n5.nabble.com/Nesting-and-AttributesToJSON-td3575.html   Hope this helps, Matt ... View more