Want to read NIFI template data in run time.

[#1]

Hello,

I am going to make a custom processor which needs NIFI template xml file's data(existing saved template) in run time, is this possible in nifi to read existing nifi template file's data in run time.

Thanks

[#2 · Accepted solution]

That's interesting.

You can read it just like a regular XML with a SAX or DOM parser like Jackson.

What do you need from the XML?

You could read configuration file elsewhere or pass it into your processor.

https://nifi.apache.org/developer-guide.html

[#3]

Thanks Timothy

I have find out the way to read template's xml file in onTrigger method of my custom processor, but I am getting some issues.

I am using getTemplates() method of StandardNiFiServiceFacade class that implements NiFiServiceFacade interface, and I make object of that interface like this --

private NiFiServiceFacade serviceFacade = new StandardNiFiServiceFacade();

in my custom processor's code. But when I am going to up my nifi server, I got error on this line.

Below are the error I am getting:

java.util.ServiceConfigurationError: org.apache.nifi.processor.Processor: Provider org.apache.nifi.processors.hadoop.SparkConnector could not be instantiated at java.util.ServiceLoader.fail(ServiceLoader.java:232) ~[na:1.8.0_111] at java.util.ServiceLoader.access$100(ServiceLoader.java:185) ~[na:1.8.0_111] at java.util.ServiceLoader$LazyIterator.nextService(ServiceLoader.java:384) ~[na:1.8.0_111] at java.util.ServiceLoader$LazyIterator.next(ServiceLoader.java:404) ~[na:1.8.0_111] at java.util.ServiceLoader$1.next(ServiceLoader.java:480) ~[na:1.8.0_111] at org.apache.nifi.nar.ExtensionManager.loadExtensions(ExtensionManager.java:116) ~[nifi-nar-utils-1.1.2.jar:1.1.2] at org.apache.nifi.nar.ExtensionManager.discoverExtensions(ExtensionManager.java:97) ~[nifi-nar-utils-1.1.2.jar:1.1.2] at org.apache.nifi.NiFi.<init>(NiFi.java:139) ~[nifi-runtime-1.1.2.jar:1.1.2] at org.apache.nifi.NiFi.main(NiFi.java:262) ~[nifi-runtime-1.1.2.jar:1.1.2]

Caused by: java.lang.NoClassDefFoundError: org/apache/nifi/web/revision/RevisionClaim at org.apache.nifi.processors.hadoop.SparkConnector.<init>(SparkConnector.java:53) ~[nifi-hdfs-processors-1.1.2.jar:1.1.2] at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) ~[na:1.8.0_111] at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62) ~[na:1.8.0_111] at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) ~[na:1.8.0_111] at java.lang.reflect.Constructor.newInstance(Constructor.java:423) ~[na:1.8.0_111] at java.lang.Class.newInstance(Class.java:442) ~[na:1.8.0_111] at java.util.ServiceLoader$LazyIterator.nextService(ServiceLoader.java:380) ~[na:1.8.0_111] ... 6 common frames omitted

Caused by: java.lang.ClassNotFoundException: org.apache.nifi.web.revision.RevisionClaim at java.net.URLClassLoader.findClass(URLClassLoader.java:381) ~[na:1.8.0_111] at java.lang.ClassLoader.loadClass(ClassLoader.java:424) ~[na:1.8.0_111] at java.lang.ClassLoader.loadClass(ClassLoader.java:357) ~[na:1.8.0_111] ... 13 common frames omitted

I wont able to understand what exactly is the problem, as I have already added all required jar files in nar. Still I am getting this error. Please suggest me what I am doing wrong here or tell me some alternate way if you know that how I get all template object in TemplateEntity class in my onTrigger method of customProcessor.

Thanks in advance