[JENKINS-18381] Provide a mechanism to differentiate between node

properties that are applicable to the master node only and node properties
that can be applied to all nodes

changelog.html

@@ -90,6 +90,10 @@ Upcoming changes</a>
   <li class=rfe>
     CLI list-jobs command should list all nested jobs.
     (<a href="https://github.com/jenkinsci/jenkins/pull/793">pull request 793</a>)
+  <li class=rfe>
+    Provide a mechanism to differentiate between node properties that are applicable
+    to the master node only and node properties that can be applied to all nodes
+    (<a href="https://issues.jenkins-ci.org/browse/JENKINS-18381">issue 18381</a>)
 </ul>
 </div><!--=TRUNK-END=-->
 

core/src/main/java/hudson/Functions.java

@@ -796,6 +796,22 @@ public class Functions {
         return result;
     }
 
+    /**
+     * Returns those node properties which can be configured as global node properties.
+     *
+     * @since 1.520
+     */
+    public static List<NodePropertyDescriptor> getGlobalNodePropertyDescriptors() {
+        List<NodePropertyDescriptor> result = new ArrayList<NodePropertyDescriptor>();
+        Collection<NodePropertyDescriptor> list = (Collection) Jenkins.getInstance().getDescriptorList(NodeProperty.class);
+        for (NodePropertyDescriptor npd : list) {
+            if (npd.isApplicableAsGlobal()) {
+                result.add(npd);
+            }
+        }
+        return result;
+    }
+
     /**
      * Gets all the descriptors sorted by their inheritance tree of {@link Describable}
      * so that descriptors of similar types come nearby.

core/src/main/java/hudson/slaves/NodePropertyDescriptor.java

@@ -26,6 +26,7 @@ package hudson.slaves;
 import hudson.Extension;
 import hudson.model.Node;
 import hudson.tools.PropertyDescriptor;
+import jenkins.model.Jenkins;
 
 /**
  * Descriptor for {@link NodeProperty}.
@@ -43,4 +44,17 @@ public abstract class NodePropertyDescriptor extends PropertyDescriptor<NodeProp
 
     protected NodePropertyDescriptor() {
     }
+
+    /**
+     * Is this node property one where it makes sense to permit it as a global node property.
+     *
+     * @return {@code true} if and only if the node property can be listed as a global node property.
+     * @since 1.520
+     */
+    public boolean isApplicableAsGlobal() {
+        // preserve legacy behaviour, even if brain-dead stupid, where applying to Jenkins was the discriminator
+        // note that it would be a mistake to assume Jenkins.getInstance().getClass() == Jenkins.class
+        // the groovy code tested against app.class, so we replicate that exact logic.
+        return isApplicable(Jenkins.getInstance().getClass());
+    }
 }

core/src/main/resources/jenkins/model/GlobalNodePropertiesConfiguration/config.groovy

@@ -5,4 +5,4 @@ import hudson.Functions
 def f=namespace(lib.FormTagLib)
 
 f.descriptorList(title:_("Global properties"),  name:"globalNodeProperties",
-        instances: app.globalNodeProperties, descriptors: Functions.getNodePropertyDescriptors(app.getClass()));
+        instances: app.globalNodeProperties, descriptors: Functions.getGlobalNodePropertyDescriptors());