[PLC4X-245] [Modbus] Apache NiFi processor throws java.io.IOException after a while

• Type: Bug
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Affects Version/s: 0.7.0
• Component/s: Driver-Modbus, Integration-NiFi
• Environment: Apache NiFi 1.12.0, Win2012 Server, PLX4X Nar 0.7.0 (https://mvnrepository.com/artifact/org.apache.plc4x/plc4j-nifi-plc4x-nar/0.7.0)
• Assignee: Unassigned
• Reporter: Turker TUNALI
• Created: 28/Aug/20 10:09
• Updated: 09/Nov/22 10:19

Description

My Plc4xSourceProcessor's, PLC connection String is "modbus:tcp://10.0.2.238:502?slave=1" and PLC resource address String is "test1=holding-register:1"
 
I can get the values for 5-10 times with 5 second intervals but then I get below exception. I can read the values with the Modbus Poll application, so most probably the PLC4X side has a problem.
 
I may also get some other exceptions when starting the processor, which are also below.
 
PS: Wireshark trace is attached. I've read 16 times then I get the exception.
 

• • This is the exception which I get after some successful read operations.*
    2020-08-27 13:19:06,091 WARN [nioEventLoopGroup-8-1] io.netty.channel.DefaultChannelPipeline An exceptionCaught() event was fired, and it reached at the tail of the pipeline. It usually means the last handler in the pipeline did not handle the exception.
    java.io.IOException: An existing connection was forcibly closed by the remote host
    at sun.nio.ch.SocketDispatcher.read0(Native Method)
    at sun.nio.ch.SocketDispatcher.read(Unknown Source)
    at sun.nio.ch.IOUtil.readIntoNativeBuffer(Unknown Source)
    at sun.nio.ch.IOUtil.read(Unknown Source)
    at sun.nio.ch.SocketChannelImpl.read(Unknown Source)
    at io.netty.buffer.PooledByteBuf.setBytes(PooledByteBuf.java:253)
    at io.netty.buffer.AbstractByteBuf.writeBytes(AbstractByteBuf.java:1133)
    at io.netty.channel.socket.nio.NioSocketChannel.doReadBytes(NioSocketChannel.java:350)
    at io.netty.channel.nio.AbstractNioByteChannel$NioByteUnsafe.read(AbstractNioByteChannel.java:148)
    at io.netty.channel.nio.NioEventLoop.processSelectedKey(NioEventLoop.java:714)
    at io.netty.channel.nio.NioEventLoop.processSelectedKeysOptimized(NioEventLoop.java:650)
    at io.netty.channel.nio.NioEventLoop.processSelectedKeys(NioEventLoop.java:576)
    at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:493)
    at io.netty.util.concurrent.SingleThreadEventExecutor$4.run(SingleThreadEventExecutor.java:989)
    at io.netty.util.internal.ThreadExecutorMap$2.run(ThreadExecutorMap.java:74)
    at io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30)
    at java.lang.Thread.run(Unknown Source)
     
     
  • This is the exception which I get sometimes when starting up the processor.*
    2020-08-27 13:17:16,813 WARN [Timer-Driven Process Thread-11] o.a.n.controller.tasks.ConnectableTask Administratively Yielding Plc4xSourceProcessor[id=2f12f5b4-0174-1000-724e-a53ba0fc1652] due to uncaught Exception: java.lang.NullPointerException
    java.lang.NullPointerException: null
    at org.apache.plc4x.nifi.Plc4xSourceProcessor.onTrigger(Plc4xSourceProcessor.java:50)
    at org.apache.nifi.processor.AbstractProcessor.onTrigger(AbstractProcessor.java:27)
    at org.apache.nifi.controller.StandardProcessorNode.onTrigger(StandardProcessorNode.java:1174)
    at org.apache.nifi.controller.tasks.ConnectableTask.invoke(ConnectableTask.java:213)
    at org.apache.nifi.controller.scheduling.TimerDrivenSchedulingAgent$1.run(TimerDrivenSchedulingAgent.java:117)
    at org.apache.nifi.engine.FlowEngine$2.run(FlowEngine.java:110)
    at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source)
    at java.util.concurrent.FutureTask.runAndReset(Unknown Source)
    at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$301(Unknown Source)
    at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(Unknown Source)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
    at java.lang.Thread.run(Unknown Source)