Apache NiFi - Custom Processor

Apache NiFi is an open source platform and gives developers the options to add their custom processor in the NiFi library. Follow these steps to create a custom processor.

• Download Maven latest version from the link given below.
  https://maven.apache.org/download.cgi
• Add an environment variable named M2_HOME and set value as the installation directory of maven.
• Download Eclipse IDE from the below link.
  https://www.eclipse.org/downloads/download.php
• Open command prompt and execute Maven Archetype command.

> mvn archetype:generate

• Search for the nifi type in the archetype projects.
• Select org.apache.nifi:nifi-processor-bundle-archetype project.
• Then from the list of versions select the latest version i.e. 1.7.1 for this tutorial.
• Enter the groupId, artifactId, version, package, and artifactBaseName etc.
• Then a maven project will be created having to directories.
  • nifi-<artifactBaseName>-processors
  • nifi-<artifactBaseName>-nar
• Run the below command in nifi-<artifactBaseName>-processors directory to add the project in the eclipse.

mvn install eclipse:eclipse

• Open eclipse and select import from the file menu.
• Then select “Existing Projects into workspace” and add the project from nifi-<artifactBaseName>-processors directory in eclipse.
• Add your code in public void onTrigger(ProcessContext context, ProcessSession session) function, which runs when ever a processor is scheduled to run.
• Then package the code to a NAR file by running the below mentioned command.

mvn clean install

• A NAR file will be created at nifi--nar/target directory.
• Copy the NAR file to the lib folder of Apache NiFi and restart the NiFi.
• After successful restart of NiFi, check the processor list for the new custom processor.
• For any errors, check ./logs/nifi.log file.