CODEWITHSUNDEEP
javaapache-nifi
bsd
bsd

Reputation: 1247

nifi 1.0.0 - extend the behaviour of a standard processor

I have a custom processor that extends the MergeContent proc and when NiFi starts I have this error in logs:

2016-09-09 18:17:00,607 ERROR [main] org.apache.nifi.NiFi Failure to launch NiFi due to java.util.ServiceConfigurationError: org.apache.nifi.processor.Processor: Provider org.apache.nifi.processors.standard.DetectDuplicate could not be instantiated
java.util.ServiceConfigurationError: org.apache.nifi.processor.Processor: Provider org.apache.nifi.processors.standard.DetectDuplicate could not be instantiated
        at java.util.ServiceLoader.fail(ServiceLoader.java:232) ~[na:1.8.0_101]
        at java.util.ServiceLoader.access$100(ServiceLoader.java:185) ~[na:1.8.0_101]
        at java.util.ServiceLoader$LazyIterator.nextService(ServiceLoader.java:384) ~[na:1.8.0_101]
        at java.util.ServiceLoader$LazyIterator.next(ServiceLoader.java:404) ~[na:1.8.0_101]
        at java.util.ServiceLoader$1.next(ServiceLoader.java:480) ~[na:1.8.0_101]
        at org.apache.nifi.nar.ExtensionManager.loadExtensions(ExtensionManager.java:107) ~[nifi-nar-utils-1.0.0.jar:1.0.0]
        at org.apache.nifi.nar.ExtensionManager.discoverExtensions(ExtensionManager.java:88) ~[nifi-nar-utils-1.0.0.jar:1.0.0]
        at org.apache.nifi.NiFi.<init>(NiFi.java:135) ~[nifi-runtime-1.0.0.jar:1.0.0]
        at org.apache.nifi.NiFi.main(NiFi.java:243) ~[nifi-runtime-1.0.0.jar:1.0.0]
Caused by: java.lang.NoClassDefFoundError: org/apache/nifi/distributed/cache/client/Serializer
        at java.lang.Class.getDeclaredConstructors0(Native Method) ~[na:1.8.0_101]
        at java.lang.Class.privateGetDeclaredConstructors(Class.java:2671) ~[na:1.8.0_101]
        at java.lang.Class.getConstructor0(Class.java:3075) ~[na:1.8.0_101]
        at java.lang.Class.newInstance(Class.java:412) ~[na:1.8.0_101]
        at java.util.ServiceLoader$LazyIterator.nextService(ServiceLoader.java:380) ~[na:1.8.0_101]
        ... 6 common frames omitted
Caused by: java.lang.ClassNotFoundException: org.apache.nifi.distributed.cache.client.Serializer
        at java.net.URLClassLoader.findClass(URLClassLoader.java:381) ~[na:1.8.0_101]
        at java.lang.ClassLoader.loadClass(ClassLoader.java:424) ~[na:1.8.0_101]
        at java.lang.ClassLoader.loadClass(ClassLoader.java:357) ~[na:1.8.0_101]

On Nifi 0.6.1/ 0.7.0 it worked, but when I've tried to use PutSQL proc, I could not see in the property list the DBCPConnectionPool service populated.

Is there a proper way to extend the behaviour of a standard processor ?

Upvotes: 2

Views: 2038

Answers (2)

Israel Varea
Israel Varea

Reputation: 2630

In .pom from project nifi-mycustom-nar add following dependency:

<dependency>
   <groupId>org.apache.nifi</groupId>
   <artifactId>nifi-standard-nar</artifactId>
   <version>1.4.0</version>
   <type>nar</type>
</dependency>

Note that only one nar dependency is allowed, so if you had nifi-standard-services-api-nar depdencency, remove it.

In .pom from project nifi-mycustom-processors add following dependency:

<dependency>
        <groupId>org.apache.nifi</groupId>
        <artifactId>nifi-standard-processors</artifactId>
        <version>1.4.0</version>
        <scope>provided</scope>
</dependency>

Finally, recompile and copy your new nar file into $NIFI/lib directory.

Upvotes: 2

Bryan Bende
Bryan Bende

Reputation: 18670

If you are extending or using components from another NAR in your NAR, there needs to be a NAR dependency between them.

This page demonstrates how to setup the proper linking between a processor and a controller service in separate NARs:

https://cwiki.apache.org/confluence/display/NIFI/Maven+Projects+for+Extensions#MavenProjectsforExtensions-LinkingProcessorsandControllerServices

This GitHub project also has a fully working example for the same concept: https://github.com/bbende/nifi-dependency-example

From a dependency perspective, extending a processor and using a controller service should be the same setup, both need to be able to access something from another NAR.

Upvotes: 3

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