NiFi SpringContextProcessor interrupts the flow - spring

Question

I added a SpringContextProcessor to my NiFi flow, it executes as expected and updates the FlowFile content and attributes. But in the data provenance section of NiFi instead of seeing SEND/RECEIVE, I am seeing
03/27/2017 11:47:57.164 MDT RECEIVE 42fa1c3f-edde-4cb7-8e73-ce752f7e3d66
03/27/2017 11:47:57.163 MDT DROP 667094a7-8eef-4657-981a-dc9fdc6c4056
03/27/2017 11:47:57.163 MDT SEND 667094a7-8eef-4657-981a-dc9fdc6c4056
Looks like the original message is being dropped and replaced by a new message. I haven't seen this behavior in other components, i.e. they all seem to preserve the original Flow File UUID. Simplified version of the Spring processor code:
#ServiceActivator(inputChannel = "fromNiFi", outputChannel = "toNiFi")
public Message<byte[]> process1(Message<byte[]> inMessage) {
String inMessagePayload = new String(inMessage.getPayload());
String userId = getUserIdFromDb(inMessagePayload);
String outMessagePayload = inMessagePayload + userId;
return MessageBuilder.withPayload(outMessagePayload.getBytes())
.copyHeaders(inMessage.getHeaders())
.setHeader("userId", userId)
.build();
}
Is there a way to preserve the original Flow File UUID in the outgoing message?

Answer 1

This is probably an oversight on our end, so yes please do raise a JIRA.
However as a workaround you can try to extract FlowFile attributes from the incoming Message headers and then propagate them back to the outgoing message.
public Message<byte[]> process1(Message<byte[]> inMessage) {
String myHeader = inMessage.getHeader("someHeader");
. . .
return MessageBuilder.withPayload(outMessagePayload.getBytes())
.copyHeaders(inMessage.getHeaders())
.setHeader("userId", userId)
.setHeader("someHeader", myHeader)
.build();
}