Apache Camel SNMP 组件

Question

currently I am working on a project where I receive OPC UA data and send them via SNMP to a PRTG monitoring system. I already created the routes between OPC UA datapoints and a SNMP client (with an unique OID). The problem here is the connection to the PRTG monitoring system. When I start the connection I get a NullPointer Exception on the the SnmpTrapProducer. It seems like I cannot create a trap of type PDU in SNMPTrapProducer.java

I figured out that the PDU trap that is created in SnmpTrapProducer.process(Exchange exchange) returns the NullPointerException(you can see the parts of the class in the picture). I tried different approaches like changing message body types or different ports as well as on ip addresses. But I still get the NullPointerException.

What do I have to configure, so the trap doesn't return a NullPointer Exception?

Image of parts of the code

SnmpTrapProducer.java

...
PDU trap = exchange.getIn().getBody(PDU.class);

trap.setErrorIndex(0);
trap.setErrorStatus(0);
trap.setMaxRepetitions(0);
...

The following code is the configuration of the Camel Route

from("milo-client:opc.tcp://"
                + OpcConfiguration.getIpAdress() + ":"
                + OpcConfiguration.getPort()
                + "?node=RAW(" + snmpOidDataStructure.getOpcDataStructure().getNodeId() + ")&allowedSecurityPolicies=None")
                .to("stream:out")
                .to("snmp://10.3.248.12:5700?protocol=udp&type=TRAP&snmpVersion=1&oids=" + snmpOidDataStructure.getOid());

The message body from the OPC component looks like that:

{value=Variant{value=[LocalizedText{text=CP, locale=de}, LocalizedText{text=Video, locale=de}, LocalizedText{text=Notfallsäule, locale=de}, LocalizedText{text=CP Notruf 2 [Gleis 2], locale=de}, LocalizedText{text=, locale=de}]}, status=StatusCode{name=Good, value=0x00000000, quality=good}, sourceTime=DateTime{utcTime=131999719975360000, javaDate=Wed Apr 17 12:53:17 CEST 2019}, serverTime=DateTime{utcTime=132164793099138549, javaDate=Fri Oct 25 14:15:09 CEST 2019}}

Error Message:

java.lang.NullPointerException: null
        at org.apache.camel.component.snmp.SnmpTrapProducer.process(SnmpTrapProducer.java:112) ~[Schnittstellenadapter-1.0-SNAPSHOT-shaded.jar:1.0-SNAPSHOT]
        at org.apache.camel.util.AsyncProcessorConverterHelper$ProcessorToAsyncProcessorBridge.process(AsyncProcessorConverterHelper.java:61) ~[Schnittstellenadapter-1.0-SNAPSHOT-shaded.jar:1.0-SNAPSHOT]
        at org.apache.camel.processor.SendProcessor.process(SendProcessor.java:148) ~[Schnittstellenadapter-1.0-SNAPSHOT-shaded.jar:1.0-SNAPSHOT]
        at org.apache.camel.processor.RedeliveryErrorHandler.process(RedeliveryErrorHandler.java:548) ~[Schnittstellenadapter-1.0-SNAPSHOT-shaded.jar:1.0-SNAPSHOT]
        at org.apache.camel.processor.CamelInternalProcessor.process(CamelInternalProcessor.java:201) [Schnittstellenadapter-1.0-SNAPSHOT-shaded.jar:1.0-SNAPSHOT]
        at org.apache.camel.processor.Pipeline.process(Pipeline.java:138) [Schnittstellenadapter-1.0-SNAPSHOT-shaded.jar:1.0-SNAPSHOT]
        at org.apache.camel.processor.Pipeline.process(Pipeline.java:101) [Schnittstellenadapter-1.0-SNAPSHOT-shaded.jar:1.0-SNAPSHOT]
        at org.apache.camel.processor.CamelInternalProcessor.process(CamelInternalProcessor.java:201) [Schnittstellenadapter-1.0-SNAPSHOT-shaded.jar:1.0-SNAPSHOT]
        at org.apache.camel.processor.DelegateAsyncProcessor.process(DelegateAsyncProcessor.java:97) [Schnittstellenadapter-1.0-SNAPSHOT-shaded.jar:1.0-SNAPSHOT]
        at org.apache.camel.component.milo.client.MiloClientConsumer.handleValueUpdate(MiloClientConsumer.java:78) [Schnittstellenadapter-1.0-SNAPSHOT-shaded.jar:1.0-SNAPSHOT]
        at org.eclipse.milo.opcua.sdk.client.subscriptions.OpcUaMonitoredItem.lambda$setValueConsumer$0(OpcUaMonitoredItem.java:133) ~[Schnittstellenadapter-1.0-SNAPSHOT-shaded.jar:1.0-SNAPSHOT]
        at org.eclipse.milo.opcua.sdk.client.subscriptions.OpcUaMonitoredItem.onValueArrived(OpcUaMonitoredItem.java:191) ~[Schnittstellenadapter-1.0-SNAPSHOT-shaded.jar:1.0-SNAPSHOT]
        at org.eclipse.milo.opcua.sdk.client.subscriptions.OpcUaSubscriptionManager.lambda$null$39(OpcUaSubscriptionManager.java:700) ~[Schnittstellenadapter-1.0-SNAPSHOT-shaded.jar:1.0-SNAPSHOT]
        at org.eclipse.milo.opcua.stack.core.util.ExecutionQueue$PollAndExecute.run(ExecutionQueue.java:107) ~[Schnittstellenadapter-1.0-SNAPSHOT-shaded.jar:1.0-SNAPSHOT]
        at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source) ~[na:1.8.0_221]
        at java.util.concurrent.FutureTask.run(Unknown Source) ~[na:1.8.0_221]
        at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source) ~[na:1.8.0_221]
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source) ~[na:1.8.0_221]
        at java.lang.Thread.run(Unknown Source) ~[na:1.8.0_221]

Any help is greatly appreciated

Answer 1

The class SnmpTrapProducer throws a NPE because the message body seems to be empty .

As your picture shows, the problem is that the variable trap stays null . It should become an object on this line.

PDU trap = exchange.getIn().getBody(PDU.class);

The line gets the message body content and it wants it to be an instance of org.snmp4j.PDU .

Unfortunately you don't show the code that populates the message body, but I assume the message body is simply empty .

Try to log out the message body in your route before you pass it on to the SNMP component

 .log("Message body: ${body}") 

The other option would be that the message body is of another type than org.snmp4j.PDU , but I think then it would throw a TypeConversionException .