gradle-nar-plugin

A gradle plugin to create nar files for Apache nifi. This plugin is forked from https://github.com/sponiro/gradle-nar-plugin . Kudos to the originals contributors.

Installation

plugins {
    id 'io.github.lhotari.gradle-nar-plugin' version '0.5.1'
}

Check the Gradle plugins portal page for more details.

Usage

Run gradle nar to execute the nar task and create a nar archive.

Configuration

Nar Task

The plugin adds a new preconfigured task of type Nar named nar to the project. The Nar class extends Jar and can be modified as such. The task is configured to add all runtime dependencies and the jar archive itself to the nar archive.

Nar Parent

Nar archives can have a parent nar. The parent is optional and there can be at maximum one parent. The parent relationship is added to the manifest. To tell the plugin to add a parent you have to add a nar dependency to the nar configuration. The nar configuration is created by the plugin. Add the parent nar like this:

dependencies {
    nar 'org.apache.nifi:nifi-standard-services-api-nar:0.2.1'
}

If you add more than one dependency, it will complain and crash the build.

Manifest

The manifest of a nar file contains properties to identify the nar file and a parent nar. This plugin configures the manifest generation to contain the values from the project name, group and version. The same goes for the nar parent.

Default manifest values

Manifest Property Key	Value
Nar-Group	project.group
Nar-Id	project.name
Nar-Version	project.version
Nar-Dependency-Group	nar config group
Nar-Dependency-Id	nar config name
Nar-Dependency-Version	nar config version

Override manifest values

The plugin respects manifest overrides from the user. For example:

nar {
    manifest {
        attributes 'Nar-Group': 'overriden-nar-group-value'
    }
}

A full description can be found at https://docs.gradle.org/current/userguide/java_plugin.html#sec:jar.

Service Locator

Apache nifi uses the ServiceLocator to define processors. The Processor API explains in detail how this works. Basically, you have to add a file in META-INF/services directory named org.apache.nifi.processor.Processor. This text file contains a fully-qualified class names of your processors. One per line.