This plugin allows Jenkins plugins to behave differently based on the "environment" it is running in.

@OptionalExtension and @OptionalPackage annotations can be used to define a set of required:

• Plugins.
• Classes.
• Variants.

With this plugin, you define environment sensitive extension by marking your extension as @OptionalExtension that specifies the condition of activation.

@OptionalExtension(requirePlugins="git")
public class Foo implements ... {
   ...
}

Optional extensions can be activated by one of the following conditions:

• Presence of plugins, identified by their short names (like "git")
• Presence of a class
• Presence of a "variant" in the environment.

Active variants can be selected in several ways. Multiple variants can be independently activated. All of the variants activated in these different ways are combined together to form the effective variant set.

• Via environment variable JENKINS_VARIANT. This is a whitespace separated list of variant names. This is intended for users to configure through init scripts like /etc/default/...

• Files in the $JENKINS_HOME/variants directory. For example, if there's a file named $JENKINS_HOME/variants/cjoc, then the cjoc variant gets activated. This is also intended for users.

• META-INF/MANIFEST.MF of jenkins.war can have the Jenkins-Variant attribute in its main section. This whitespace separated list of variant names is intended to be used by people who create custom distributions of Jenkins.

This addition will allow more controlled extension enablement beyond @Extension(optional=true). For example, it is often common for a plugin to define some additional integration extension that only kicks in when another plugin is present.

Beyond that, at CloudBees, we reuse Jenkins as the platform for other Jenkins-like services. Those are built on the same Jenkins core, but they do not build and instead do other things, such as "CloudBees Jenkins Operations Center."

This mechanism also lets us define multi-modal plugin that can run in such variants and behave differently. In this way, we can use the same plugin across different variants of Jenkins, so that users can think of this as installing one plugin in the whole network of Jenkins variants.

For recent versions, see GitHub Releases

For versions 1.2 and older, see see CHANGELOG.md