add changes to release resources when the channel becomes inactive

[frankpuppa]

While I was looking into this issue I found out that there are two leaks. The first is related to the RequestTransactionManager and the other is from the NettyHashTimerTimeoutManager. As I was mentioning in the issue I opened last week, this leaks happens when the PLC goes offline and back online and the client tries to reconnecting to it in a cycle.

I was only able to test this on the modbus simulator which seems to work ok with the changes I made on this branch.
Please provide me a feedback or any consideration. I am attaching also a small video which shows that the resources are freed as expected.

Issue link

Screencast.2025-09-03.09.58.05.mp4

[chrisdutz]

Hi Frank,
do I understand things correctly? The main difference is that you're overriding channelInactive in Plc4xNettyWrapper and forwarding that to the individual implementations?
Definitely looks sensible.

Chris

[chrisdutz]

Could you please increase the log level for your additional log output to something "debug" or "trace"? "info" makes the drivers quite noisy.

[chrisdutz]

Please set this to "debug" or "trace"

[chrisdutz]

Please set this to "debug" or "trace"

[frankpuppa]

Hi Frank, do I understand things correctly? The main difference is that you're overriding channelInactive in Plc4xNettyWrapper and forwarding that to the individual implementations? Definitely looks sensible.

Chris

Hello Chris,
Yes exactly, basically when the plc goes offline a channelInactive event is propagated. Within the nettywrapper I basically propagate the event in the implementations which can eventually shutdown the RequestTransactionManager and release the resources. I was able to test the functionality only for the ModbusTcpProtocol. I will fix the verbosity asap.