Maven nar plugin looks to not bundle all the dependancies

scarroll — Thu, 12 Jan 2017 08:35:21 GMT

I have a custom NiFi processor that worked great up until me trying use a distributedMapCache. I tried to include it like:

import org.apache.nifi.distributed.cache.client.DistributedMapCacheClient;
...
public class ListBox extends AbstractListProcessor {
...
    public static final PropertyDescriptor DISTRIBUTED_CACHE_SERVICE = new PropertyDescriptor.Builder()
            .name("Distributed Cache Service")
            .description("Specifies the Controller Service that should be used to maintain state about what has been pulled from HDFS so that if a new node "
                    + "begins pulling data, it won't duplicate all of the work that has been done.")
            .required(false)
            .identifiesControllerService(DistributedMapCacheClient.class)
            .build();

But then when I mvn clean install and copy the nar over I get the following error:

java.util.ServiceConfigurationError: org.apache.nifi.processor.Processor: Provider org.hortonworks.processors.boxconnector.ListBox could not be instantiated
        at java.util.ServiceLoader.fail(ServiceLoader.java:232) ~[na:1.8.0_91]
        at java.util.ServiceLoader.access$100(ServiceLoader.java:185) ~[na:1.8.0_91]
        at java.util.ServiceLoader$LazyIterator.nextService(ServiceLoader.java:384) ~[na:1.8.0_91]
        at java.util.ServiceLoader$LazyIterator.next(ServiceLoader.java:404) ~[na:1.8.0_91]
        at java.util.ServiceLoader$1.next(ServiceLoader.java:480) ~[na:1.8.0_91]
        at org.apache.nifi.nar.ExtensionManager.loadExtensions(ExtensionManager.java:116) ~[nifi-nar-utils-1.1.0.jar:1.1.0]
        at org.apache.nifi.nar.ExtensionManager.discoverExtensions(ExtensionManager.java:97) ~[nifi-nar-utils-1.1.0.jar:1.1.0]
        at org.apache.nifi.NiFi.<init>(NiFi.java:139) ~[nifi-runtime-1.1.0.jar:1.1.0]
        at org.apache.nifi.NiFi.main(NiFi.java:262) ~[nifi-runtime-1.1.0.jar:1.1.0]
Caused by: java.lang.NoClassDefFoundError: org/apache/nifi/distributed/cache/client/DistributedMapCacheClient

I also have the dependancy configured in my pom.xml file:

<dependency>
    <groupId>org.apache.nifi</groupId>
    <artifactId>nifi-distributed-cache-client-service-api</artifactId>
</dependency>

If I copy over the distributed map cache nar before bundling it works fine. Is there somewhere else I have to list the dependancy to get it bundled into the nar?

Re: Maven nar plugin looks to not bundle all the dependancies

bbende — Thu, 12 Jan 2017 22:48:33 GMT

There is a specific way that processors and controller services are linked together....

Your processor JAR project should have a provided dependency on the API of the controller service, and your processor NAR project should have a NAR dependency on the API NAR.

Check out these resources for examples:

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

https://github.com/bbende/nifi-dependency-example

Re: Maven nar plugin looks to not bundle all the dependancies

mburgess — Thu, 12 Jan 2017 22:52:15 GMT

Specifically, in your processor POM (which you list above), Bryan is saying that under that dependency you should have a <scope>provided</scope> line, and in your NAR POM you should include:

<dependency>
  <groupId>org.apache.nifi</groupId>
  <artifactId>nifi-standard-services-api-nar</artifactId>
  <type>nar</type>
</dependency>

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Maven nar plugin looks to not bundle all the dependancies

Re: Maven nar plugin looks to not bundle all the dependancies

Re: Maven nar plugin looks to not bundle all the dependancies