Collecting value from OPCUA server in Nifi

Question

I am following the steps described in https://community.hortonworks.com/articles/90355/collect-data-from-opc-ua-protocol.html to connect to an OPC UA server from NiFi.

I built https://github.com/wadesalazar/NIFI-OPCUA from source code using Maven. The result was several nar files and jar files. The jar and nar obtained for me are:

opc-ua-stack-1.03.341.0-SNAPSHOT.jar

nifi-opcua-bundle-processors-0.0.1-SNAPSHOT.jar

nifi-opcua-service-0.0.1-SNAPSHOT.jar

nifi-opcua-service-api-0.0.1-SNAPSHOT.jar

opc-deploy-local-0.0.1-SNAPSHOT.jar

nifi-opcua-service-api-nar-0.0.1-SNAPSHOT.nar

nifi-opcua-service-nar-0.0.1-SNAPSHOT.nar

nifi-opcua-bundle-nar-0.0.1-SNAPSHOT.nar

If i paste all the nar and jar files in the lib folder of nifi , the nifi crashes when starting it. The error is:

org.apache.nifi.processor.Processor: Provider com.kentender.nifi.nifi_opcua_bundle.GetNodeIds could not be instantiated
java.util.ServiceConfigurationError: org.apache.nifi.processor.Processor: Provider com.kentender.nifi.nifi_opcua_bundle.GetNodeIds could not be instantiated
    at java.util.ServiceLoader.fail(ServiceLoader.java:232)
    at java.util.ServiceLoader.access$100(ServiceLoader.java:185)
    at java.util.ServiceLoader$LazyIterator.nextService(ServiceLoader.java:384)
    at java.util.ServiceLoader$LazyIterator.next(ServiceLoader.java:404)
    at java.util.ServiceLoader$1.next(ServiceLoader.java:480)
    at org.apache.nifi.nar.ExtensionManager.loadExtensions(ExtensionManager.java:138)
    at org.apache.nifi.nar.ExtensionManager.discoverExtensions(ExtensionManager.java:104)
    at org.apache.nifi.web.server.JettyServer.start(JettyServer.java:699)
    at org.apache.nifi.NiFi.<init>(NiFi.java:160)
    at org.apache.nifi.NiFi.main(NiFi.java:267)
Caused by: java.lang.NoClassDefFoundError: org/apache/nifi/processor/util/StandardValidators
    at com.kentender.nifi.nifi_opcua_bundle.GetNodeIds.<clinit>(GetNodeIds.java:55)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
    at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
    at java.lang.Class.newInstance(Class.java:442)
    at java.util.ServiceLoader$LazyIterator.nextService(ServiceLoader.java:380)
    ... 7 common frames omitted
Caused by: java.lang.ClassNotFoundException: org.apache.nifi.processor.util.StandardValidators
    at java.net.URLClassLoader.findClass(URLClassLoader.java:381)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:335)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
    ... 14 common frames omitted
2017-07-27 18:24:14,184 INFO [Thread-1] org.apache.nifi.NiFi Initiating shutdown of Jetty web server...
2017-07-27 18:24:14,184 INFO [Thread-1] org.apache.nifi.NiFi Jetty web server shutdown completed (nicely or otherwise).

If I paste only nar files, the Nifi boots up and i am able to see the custom GetNodeIds processor but i am unable to receive the data from OPCUA server. The service throws an error like

java.lang.noclassdeffounderror: org/bouncycastle/crypto/DataLengthException

Which nar and jar is to be copied to lib folder of NiFi so as to make it work and how is the process correct to proceed.

daggett daggett · Accepted Answer · 2017-07-27T20:25:06

quite sure that jar files you received after compile are included into nar files.

so you should copy only nar into lib dir.

but according to the following document upc-ua requires additional jars:

https://github.com/OPCFoundation/UA-Java#runtime-dependencies

just copy additional required libraries into lib folder.

Collecting value from OPCUA server in Nifi

2 Answers