Jenkins HelloWorld plugin does not persist config after restart

Question

I have been trying to create my first jenkins plugin. Everything is great except that the global config does not persist after the jenkins service is restarted.

THe config saves fine as long as the service is not restarted.

The global config jelly file...

<j:jelly xmlns:j="jelly:core" xmlns:st="jelly:stapler" xmlns:d="jelly:define" xmlns:l="/lib/layout" xmlns:t="/lib/hudson" xmlns:f="/lib/form">

Jenkins uses a set of tag libraries to provide uniformity in forms.
To determine where this tag is defined, first check the namespace URI,
and then look under $JENKINS/views/. For example, <f:section> is defined
in $JENKINS/views/lib/form/section.jelly.

It's also often useful to just check other similar scripts to see what
tags they use. Views are always organized according to its owner class,
so it should be straightforward to find them.
-->
<f:section title="Hello World Builder">
  <f:entry title="French" field="useFrench"
    description="Check if we should say hello in French">
    <f:checkbox />
  </f:entry>
</f:section>
</j:jelly>

After save jenkins is constructing a config file named

examplePlugin.examplePlugin.HelloWorldBuilder.xml

With Content false

The descriptor itself is the following.

// Overridden for better type safety.
// If your plugin doesn't really define any property on Descriptor,
// you don't have to do this.
@Override
public DescriptorImpl getDescriptor() {
    return (DescriptorImpl)super.getDescriptor();
}

/**
 * Descriptor for {@link HelloWorldBuilder}. Used as a singleton.
 * The class is marked as public so that it can be accessed from views.
 *
 * <p>
 * See <tt>src/main/resources/hudson/plugins/hello_world/HelloWorldBuilder/*.jelly</tt>
 * for the actual HTML fragment for the configuration screen.
 */
@Extension // This indicates to Jenkins that this is an implementation of an extension point.
public static final class DescriptorImpl extends BuildStepDescriptor<Builder> {
    /**
     * To persist global configuration information,
     * simply store it in a field and call save().
     *
     * <p>
     * If you don't want fields to be persisted, use <tt>transient</tt>.
     */
    private boolean useFrench;

    /**
     * Performs on-the-fly validation of the form field 'name'.
     *
     * @param value
     *      This parameter receives the value that the user has typed.
     * @return
     *      Indicates the outcome of the validation. This is sent to the browser.
     */
    public FormValidation doCheckName(@QueryParameter String value)
            throws IOException, ServletException {
        if (value.length() == 0)
            return FormValidation.error("Please set a name");
        if (value.length() < 4)
            return FormValidation.warning("Isn't the name too short?");
        return FormValidation.ok();
    }

    public boolean isApplicable(Class<? extends AbstractProject> aClass) {
        // Indicates that this builder can be used with all kinds of project types 
        return true;
    }

    /**
     * This human readable name is used in the configuration screen.
     */
    public String getDisplayName() {
        return "Say hello world";
    }

    @Override
    public boolean configure(StaplerRequest req, JSONObject formData) throws FormException {
        // To persist global configuration information,
        // set that to properties and call save().
        useFrench = formData.getBoolean("useFrench");
        // ^Can also use req.bindJSON(this, formData);
        //  (easier when there are many fields; need set* methods for this, like setUseFrench)
        save();
        return super.configure(req,formData);
    }

    /**
     * This method returns true if the global configuration says we should speak French.
     *
     * The method name is bit awkward because global.jelly calls this method to determine
     * the initial state of the checkbox by the naming convention.
     */
    public boolean getUseFrench() {
        return useFrench;
    }
}

Any help with why this is not reloading on reboot would be very helpful, since this seems to be a problem with the example project created by the maven archetype.

Answer 1

So this is problem with the hello world application. You need to define in your constructor that you want to load the configuration.

public DescriptorImpl(){
        load();
    }

That fixes the issue I was seeing with the configuration not being persisted.