How to extend Jenkins job page with new links and icons

After a lot of trial and error I figured out the solution.

All in all you need two different things in your project:

1) A class that inherits from ProminentProjectAction:

import hudson.model.ProminentProjectAction;

public class MyProjectAction implements ProminentProjectAction {

    @Override
    public String getIconFileName() {
        // return the path to the icon file
        return "/images/jenkins.png";
    }

    @Override
    public String getDisplayName() {
        // return the label for your link
        return "MyActionLink";
    }

    @Override
    public String getUrlName() {
        // defines the suburl, which is appended to ...jenkins/job/jobname
        return "myactionpage";
    }
}

2) Even more important is that you add this action somehow to your project.

In my case I wanted to show the link if and only if the related build step of my plugin is configured for the actual project. So I took my Builder class and overwrote the getProjectActionsMethod.

public class MyBuilder extends Builder {

    ...

    @Override
    public Collection<? extends Action> getProjectActions(AbstractProject<?,?> project) {
        List<Action> actions = new ArrayList<>();
        actions.add(new MyProjectAction());

        return actions;
    }
}

Maybe this is not the perfect solution yet (because I'm still trying to figure out how all the artifacts are working together), but it might give people which want to implement the same a good starting point.

The page, which is loaded after clicking the link is defined as index.jelly file under source/main/resources and an underlying package with the name of the package of your Action class appended by its class name (e.g. src/main/resources/org/example/myplugin/MyProjectAction).

Root Action and Actions are different. The first one goes only to initial page (root), the second one can be attach to a Project/Job or to a Build.

To create a Root Action, just need to create a class that it's:

1. Annotated with @Extension (so it can be found and automatically loaded by Jenkins)
2. Implements RootAction Interface
3. Override 3 methods: getIconFileName(), getDisplayName() and getUrlName()

For example:

@Extension
public class GoogleRootAction implements RootAction{

    @Override
    public String getIconFileName() {
        return "clipboard.png";
    }

    @Override
    public String getDisplayName() {
        return "Google URL";
    }

    @Override
    public String getUrlName() {
        return "http://www.google.pt";
    }    
}

To create an Action at a Project it's more complicated, and there's more than a way, depending of what you want.

But first, the class Action itself is the easy part, since it's very similar to a class RootAction. It's not annotated with @Extension and implements Action interface instead of RootAction.

For example:

public class LatestConsoleProjectAction implements Action {

    private AbstractProject<?, ?> project;

    @Override
    public String getIconFileName() {
        return (Jenkins.RESOURCE_PATH + "/images/48x48/terminal.png").replaceFirst("^/", "");
    }

    @Override
    public String getDisplayName() {
        return Messages.Latest_Console_Project_Action();
    }

    @Override
    public String getUrlName() {
        return "lastBuild/console";
    }

    public LatestConsoleProjectAction(final AbstractProject<?, ?> project) {
        this.project = project;
    }

}

The tricky part is to inform jenkins that this class Action exists. As I said, there are different ways.

For instance, one can associate an Action to a Builder or Publisher or other by just overriding getProjectAction() method at those classes.

For example:

@Override
public Action getProjectAction(AbstractProject<?, ?> project) {
    return new LatestConsoleProjectAction(project);
}

But this way, the Action link will only show on Project left menu, if the corresponding Builder or Publisher is used by the job (or selected at Job configurations).

Another way, that always shows your Action link on left menu, it's create a factory class to inform jenkins. There are many factories, but at my example I will use TransientProjectActionFactory class.

For this, one will need to create a class that:

1. It's annotated with @Extensions
2. Extends TransientProjectActionFactory class (or another Factory class)
3. Override createFor method to create your class Action associated with Project object

For example:

@Extension
public class LatestConsoleProjectActionFactory extends TransientProjectActionFactory {

    @Override
    public Collection<? extends Action> createFor(AbstractProject abstractProject) {

        return Collections.singletonList(new LatestConsoleProjectAction(abstractProject));
    }
}

One can still filter project object to just the projects types you want. The one you don't want, just return Collections.emptyList().

Beside this two ways, I think there are others. You can see this link to reference: https://wiki.jenkins-ci.org/display/JENKINS/Action+and+its+family+of+subtypes

Although, they refer to addAction method and others, but I couldn't use it (I have 2.19.2 Jenkins version). Also they refer groovy, but I didn't try it, since I want to stick with Java :)

Btw, my example will create an action link to open console page of last build. Useful to avoid selecting last build and then select his console page.