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https://issues.apache.org/jira/browse/METRON-777?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16117960#comment-16117960
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ASF GitHub Bot commented on METRON-777:
---------------------------------------
Github user mattf-horton commented on a diff in the pull request:
https://github.com/apache/metron/pull/530#discussion_r131764397
--- Diff: bundles-lib/README.md ---
@@ -0,0 +1,79 @@
+# Apache Metron Bundles
+
+Apache Metron Bundles and this documentation are a derivitave of the
[Apache Nifi](http://www.nifi.apache.org)
[NARs](http://nifi.apache.org/developer-guide.html).
+
+When software from many different organizations is all hosted within
+the same environment, Java ClassLoaders quickly
+become a concern. If multiple components have a dependency on the same
+library but each depends on a different
+version, many problems arise, typically resulting in unexpected
+behavior or `NoClassDefFoundError` errors occurring.
+In order to prevent these issues from becoming problematic, Apache NiFi
+introduces the notion of a NiFi Archive, or NAR. The Apache Metron
project has adapted and extended the NAR system as
+Apache Metron Bundles.
+
+A BUNDLE allows several components and their dependencies to be packaged
+together into a single package.
+The BUNDLE package is then provided ClassLoader isolation from other
BUNDLES
+packages. Developers should always deploy their Apache Metron Extensions
as BUNDLE packages.
+
+To achieve this, a developer creates a new Maven Artifact, which we
+refer to as the BUNDLE artifact. The packaging is
+set to `bundle`. The `dependencies` section of the POM is then created so
+that the BUNDLE has a dependency on all Extension Components that are to
be included within the BUNDLE.
+
+In order to use a packaging of `bundle`, we must use the
`bundles-maven-plugin` module.
+This is included by adding the following snippet to the bundle's pom.xml:
+
+
+```xml
+<build>
+ <plugins>
+ <plugin>
+ <groupId>org.apache.metron</groupId>
+ <artifactId>bundles-maven-plugin</artifactId>
+ <version>0.4.0</version>
--- End diff --
0.4.1 is the minimum version that actually has bundles-maven-plugin.
> Create a plugin system for Metron based on 'NAR'
> ------------------------------------------------
>
> Key: METRON-777
> URL: https://issues.apache.org/jira/browse/METRON-777
> Project: Metron
> Issue Type: New Feature
> Reporter: Otto Fowler
> Assignee: Otto Fowler
>
> The success of the Metron project will be greatly dependent on community
> participation, and with that the ability to adapt and extend Metron without
> having to maintain a fork of the project.
> As organizations and individuals look to extend the Metron system with custom
> parsers, enrichments, and stellar functions that may be proprietary in
> nature, the ability to develop and deploy these extensions outside the Metron
> code base is critically important.
> To that end, and after community discussion and proposal we create or
> formalize the 'plugin' development story in Metron.
> The proposal is to adapt the Apache Nifi NAR system for use in Metron. This
> will provide the system with:
> * archetype(s) for developer projects and independent development
> * defined packaging and metadata for 'plugin' products
> * loading and instantiation with classloader isolation capabilities
> * removing the necessity for shading plugin jars
> These capabilities will also enable other features, such as plugin lifecycle,
> plugin configuration+redeployment, and other things.
> The plugin archetypes and their installation will be a followon
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