Hi
I have been taking a look into the possibility of adding a PLC4x Listener to
the NiFi integration.
Under my research, and following how most of the ListenXXX processors in the
standard-bundle of NiFi are, a good solution would be:
* A processor that starts a thread when it is scheduled.
* That thread connects to the plc and appends the messages received into a
queue.
* The processor reads the messages from this queue only running when not
empty.
In particular ListenTCP and ListenUDP would be the closest ones to the
implementation I describe.
In order to account for inevitable disconnections I suggest including an
additional queue prior to the queue that connects to the processor. Its
function would be to check if the time to the last event is greater than x
amount and reconnect in that case.
As a proof of concept I already have a working version on
https://github.com/zylklab/plc4x/tree/feature/nifi-integration-record-listener.
I would appreciate your opinion on this feature.
If you like it I can create a PR.
Thanks you for your time!
Unai Lería
