Custom nifi Processor build Error: [ERROR] Could not generate extensions' documentation : Any Solution/workaround?

[#1]

Hi,

I am trying to build custom nifi processor with controller service, I have configured projects setting to build nar files, while building getting following error, this looks to be from nifi libraries, plz let me know is there any solution or workaround exiting for this.

[ERROR] Could not generate extensions' documentation
org.apache.maven.plugin.MojoExecutionException: Failed to create Extension Documentation
at org.apache.nifi.NarMojo.generateDocumentation (NarMojo.java:596)
at org.apache.nifi.NarMojo.execute (NarMojo.java:499)
at org.apache.maven.plugin.DefaultBuildPluginManager.executeMojo (DefaultBuildPluginManager.java:137)
at org.apache.maven.lifecycle.internal.MojoExecutor.execute (MojoExecutor.java:210)
at org.apache.maven.lifecycle.internal.MojoExecutor.execute (MojoExecutor.java:156)
at org.apache.maven.lifecycle.internal.MojoExecutor.execute (MojoExecutor.java:148)
at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject (LifecycleModuleBuilder.java:117)
at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject (LifecycleModuleBuilder.java:81)
at org.apache.maven.lifecycle.internal.builder.singlethreaded.SingleThreadedBuilder.build (SingleThreadedBuilder.java:56)
at org.apache.maven.lifecycle.internal.LifecycleStarter.execute (LifecycleStarter.java:128)
at org.apache.maven.DefaultMaven.doExecute (DefaultMaven.java:305)
at org.apache.maven.DefaultMaven.doExecute (DefaultMaven.java:192)
at org.apache.maven.DefaultMaven.execute (DefaultMaven.java:105)
at org.apache.maven.cli.MavenCli.execute (MavenCli.java:957)
at org.apache.maven.cli.MavenCli.doMain (MavenCli.java:289)
at org.apache.maven.cli.MavenCli.main (MavenCli.java:193)
at jdk.internal.reflect.NativeMethodAccessorImpl.invoke0 (Native Method)
at jdk.internal.reflect.NativeMethodAccessorImpl.invoke (NativeMethodAccessorImpl.java:62)
at jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke (DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke (Method.java:567)
at org.codehaus.plexus.classworlds.launcher.Launcher.launchEnhanced (Launcher.java:282)
at org.codehaus.plexus.classworlds.launcher.Launcher.launch (Launcher.java:225)
at org.codehaus.plexus.classworlds.launcher.Launcher.mainWithExitCode (Launcher.java:406)
at org.codehaus.plexus.classworlds.launcher.Launcher.main (Launcher.java:347)
Caused by: java.lang.NullPointerException
at org.apache.nifi.NarMojo.getRequiredServiceDefinitions (NarMojo.java:708)
at org.apache.nifi.NarMojo.writeDocumentation (NarMojo.java:634)
at org.apache.nifi.NarMojo.writeDocumentation (NarMojo.java:605)
at org.apache.nifi.NarMojo.generateDocumentation (NarMojo.java:577)
at org.apache.nifi.NarMojo.execute (NarMojo.java:499)
at org.apache.maven.plugin.DefaultBuildPluginManager.executeMojo (DefaultBuildPluginManager.java:137)
at org.apache.maven.lifecycle.internal.MojoExecutor.execute (MojoExecutor.java:210)
at org.apache.maven.lifecycle.internal.MojoExecutor.execute (MojoExecutor.java:156)
at org.apache.maven.lifecycle.internal.MojoExecutor.execute (MojoExecutor.java:148)
at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject (LifecycleModuleBuilder.java:117)
at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject (LifecycleModuleBuilder.java:81)
at org.apache.maven.lifecycle.internal.builder.singlethreaded.SingleThreadedBuilder.build (SingleThreadedBuilder.java:56)
at org.apache.maven.lifecycle.internal.LifecycleStarter.execute (LifecycleStarter.java:128)
at org.apache.maven.DefaultMaven.doExecute (DefaultMaven.java:305)
at org.apache.maven.DefaultMaven.doExecute (DefaultMaven.java:192)
at org.apache.maven.DefaultMaven.execute (DefaultMaven.java:105)
at org.apache.maven.cli.MavenCli.execute (MavenCli.java:957)
at org.apache.maven.cli.MavenCli.doMain (MavenCli.java:289)
at org.apache.maven.cli.MavenCli.main (MavenCli.java:193)
at jdk.internal.reflect.NativeMethodAccessorImpl.invoke0 (Native Method)
at jdk.internal.reflect.NativeMethodAccessorImpl.invoke (NativeMethodAccessorImpl.java:62)
at jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke (DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke (Method.java:567)
at org.codehaus.plexus.classworlds.launcher.Launcher.launchEnhanced (Launcher.java:282)
at org.codehaus.plexus.classworlds.launcher.Launcher.launch (Launcher.java:225)
at org.codehaus.plexus.classworlds.launcher.Launcher.mainWithExitCode (Launcher.java:406)
at org.codehaus.plexus.classworlds.launcher.Launcher.main (Launcher.java:347)
[INFO] ------------------------------------------------------------------------
[INFO] Reactor Summary for custom-processor 1.0-SNAPSHOT:
[INFO]
[INFO] custom-processor ................................... SUCCESS [ 6.729 s]
[INFO] nifi-sample-api .................................... SUCCESS [ 4.566 s]
[INFO] nifi-sample ........................................ SUCCESS [ 12.118 s]
[INFO] nifi-custom-processors ............................. SUCCESS [ 10.350 s]
[INFO] nifi-custom-nar .................................... FAILURE [ 4.535 s]
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 44.067 s
[INFO] Finished at: 2020-04-06T22:23:28+05:30
[INFO] ------------------------------------------------------------------------
[ERROR] Failed to execute goal org.apache.nifi:nifi-nar-maven-plugin:1.3.1:nar (default-nar) on project nifi-custom-nar: Failed to create Extension Documentation: NullPointerException -> [Help 1]

[#2]

I am using latest nifi version ..

[INFO] Generating documentation for NiFi extensions in the NAR...
[INFO] Found a dependency on version 1.11.4 of NiFi API

[#3]

I ran into the same issue but with NiFi 1.10.0

I can build the project locally but not on Jenkins.

Did you resolve the issue? 

[#4]

Hi, @murali2425 @vchhipa It seems some dependency issue while building your custom NiFi Processor,  org.apache.nifi:nifi-standard-services-api-nar dependency needs to be added in pom.xml of nifi-*-nar module. Ref here 

<dependency>
    <groupId>org.apache.nifi</groupId>
    <artifactId>nifi-standard-services-api-nar</artifactId>
    <version>1.11.3</version>
    <type>nar</type>
</dependency>

 
Please modify your pom.xml and rebuild and see whether that fixes the issue. Please accept the answer you found most useful.