Allow customization of NodeProvisioner.PlannedNode using extension point

src/main/java/org/csanchez/jenkins/plugins/kubernetes/KubernetesCloud.java

@@ -51,7 +51,6 @@
 import hudson.Util;
 import hudson.init.InitMilestone;
 import hudson.init.Initializer;
-import hudson.model.Computer;
 import hudson.model.Descriptor;
 import hudson.model.Label;
 import hudson.model.Node;
@@ -405,9 +404,7 @@ public synchronized Collection<NodeProvisioner.PlannedNode> provision(@CheckForN
                     if (!addProvisionedSlave(t, label)) {
                         break;
                     }
-
-                    r.add(new NodeProvisioner.PlannedNode(t.getDisplayName(), Computer.threadPoolForRemoting
-                                .submit(new ProvisioningCallback(this, t, label)), 1));
+                    r.add(PlannedNodeBuilderFactory.createInstance().cloud(this).template(t).label(label).build());
                 }
                 if (r.size() > 0) {
                     // Already found a matching template
@@ -487,6 +484,15 @@ public PodTemplate getTemplate(@CheckForNull Label label) {
         return PodTemplateUtils.getTemplateByLabel(label, getAllTemplates());
     }
 
+    /**
+     * Unwraps the given pod template.
+     * @param podTemplate the pod template to unwrap.
+     * @return the unwrapped pod template
+     */
+    public PodTemplate getUnwrappedTemplate(PodTemplate podTemplate) {
+        return PodTemplateUtils.unwrap(podTemplate, getDefaultsProviderTemplate(), getAllTemplates());
+    }
+
     /**
      * Gets all PodTemplates that have the matching {@link Label}.
      * @param label label to look for in templates

src/main/java/org/csanchez/jenkins/plugins/kubernetes/KubernetesSlave.java

@@ -14,6 +14,7 @@
 
 import org.apache.commons.lang.RandomStringUtils;
 import org.apache.commons.lang.StringUtils;
+import org.apache.commons.lang.Validate;
 import org.jenkinsci.plugins.durabletask.executors.Messages;
 import org.jenkinsci.plugins.durabletask.executors.OnceRetentionStrategy;
 import org.jvnet.localizer.Localizable;
@@ -29,6 +30,8 @@
 import hudson.model.TaskListener;
 import hudson.slaves.AbstractCloudSlave;
 import hudson.slaves.Cloud;
+import hudson.slaves.CloudRetentionStrategy;
+import hudson.slaves.ComputerLauncher;
 import hudson.slaves.OfflineCause;
 import hudson.slaves.RetentionStrategy;
 import io.fabric8.kubernetes.client.KubernetesClient;
@@ -62,7 +65,7 @@ public PodTemplate getTemplate() {
     }
 
     /**
-     * @deprecated Use {@link #KubernetesSlave(PodTemplate, String, String, String, RetentionStrategy)} instead.
+     * @deprecated Use {@link Builder} instead.
      */
     @Deprecated
     public KubernetesSlave(PodTemplate template, String nodeDescription, KubernetesCloud cloud, String labelStr)
@@ -72,7 +75,7 @@ public KubernetesSlave(PodTemplate template, String nodeDescription, KubernetesC
     }
 
     /**
-     * @deprecated Use {@link #KubernetesSlave(PodTemplate, String, String, String, RetentionStrategy)} instead.
+     * @deprecated Use {@link Builder} instead.
      */
     @Deprecated
     public KubernetesSlave(PodTemplate template, String nodeDescription, KubernetesCloud cloud, Label label)
@@ -81,7 +84,7 @@ public KubernetesSlave(PodTemplate template, String nodeDescription, KubernetesC
     }
 
     /**
-     * @deprecated Use {@link #KubernetesSlave(PodTemplate, String, String, String, RetentionStrategy)} instead.
+     * @deprecated Use {@link Builder} instead.
      */
     @Deprecated
     public KubernetesSlave(PodTemplate template, String nodeDescription, KubernetesCloud cloud, String labelStr,
@@ -90,18 +93,27 @@ public KubernetesSlave(PodTemplate template, String nodeDescription, KubernetesC
         this(template, nodeDescription, cloud.name, labelStr, rs);
     }
 
-    @DataBoundConstructor
+    /**
+     * @deprecated Use {@link Builder} instead.
+     */
+    @Deprecated
+    @DataBoundConstructor // make stapler happy. Not actually used.
     public KubernetesSlave(PodTemplate template, String nodeDescription, String cloudName, String labelStr,
                            RetentionStrategy rs)
             throws Descriptor.FormException, IOException {
+        this(getSlaveName(template), template, nodeDescription, cloudName, labelStr, new KubernetesLauncher(), rs);
+    }
 
-        super(getSlaveName(template),
+    protected KubernetesSlave(String name, PodTemplate template, String nodeDescription, String cloudName, String labelStr,
+                           ComputerLauncher computerLauncher, RetentionStrategy rs)
+            throws Descriptor.FormException, IOException {
+        super(name,
                 nodeDescription,
                 template.getRemoteFs(),
                 1,
                 template.getNodeUsageMode() != null ? template.getNodeUsageMode() : Node.Mode.NORMAL,
                 labelStr == null ? null : labelStr,
-                new KubernetesLauncher(),
+                computerLauncher,
                 rs,
                 template.getNodeProperties());
 
@@ -257,6 +269,118 @@ public int hashCode() {
         return result;
     }
 
+    /**
+     * Returns a new {@link Builder} instance.
+     * @return a new {@link Builder} instance.
+     */
+    public static Builder builder() {
+        return new Builder();
+    }
+
+    /**
+     * Builds a {@link KubernetesSlave} instance.
+     */
+    public static class Builder {
+        private String name;
+        private String nodeDescription;
+        private PodTemplate podTemplate;
+        private KubernetesCloud cloud;
+        private String label;
+        private ComputerLauncher computerLauncher;
+        private RetentionStrategy retentionStrategy;
+
+        /**
+         * @param name The name of the future {@link KubernetesSlave}
+         * @return the current instance for method chaining
+         */
+        public Builder name(String name) {
+            this.name = name;
+            return this;
+        }
+
+        /**
+         * @param nodeDescription The node description of the future {@link KubernetesSlave}
+         * @return the current instance for method chaining
+         */
+        public Builder nodeDescription(String nodeDescription) {
+            this.nodeDescription = nodeDescription;
+            return this;
+        }
+
+        /**
+         * @param podTemplate The pod template the future {@link KubernetesSlave} has been created from
+         * @return the current instance for method chaining
+         */
+        public Builder podTemplate(PodTemplate podTemplate) {
+            this.podTemplate = podTemplate;
+            return this;
+        }
+
+        /**
+         * @param cloud The cloud that is provisioning the {@link KubernetesSlave} instance.
+         * @return the current instance for method chaining
+         */
+        public Builder cloud(KubernetesCloud cloud) {
+            this.cloud = cloud;
+            return this;
+        }
+
+        /**
+         * @param label The label the {@link KubernetesSlave} has.
+         * @return the current instance for method chaining
+         */
+        public Builder label(String label) {
+            this.label = label;
+            return this;
+        }
+
+        /**
+         * @param computerLauncher The computer launcher to use to launch the {@link KubernetesSlave} instance.
+         * @return the current instance for method chaining
+         */
+        public Builder computerLauncher(ComputerLauncher computerLauncher) {
+            this.computerLauncher = computerLauncher;
+            return this;
+        }
+
+        /**
+         * @param retentionStrategy The retention strategy to use for the {@link KubernetesSlave} instance.
+         * @return the current instance for method chaining
+         */
+        public Builder retentionStrategy(RetentionStrategy retentionStrategy) {
+            this.retentionStrategy = retentionStrategy;
+            return this;
+        }
+
+        private RetentionStrategy determineRetentionStrategy() {
+            if (podTemplate.getIdleMinutes() == 0) {
+                return new OnceRetentionStrategy(cloud.getRetentionTimeout());
+            } else {
+                return new CloudRetentionStrategy(podTemplate.getIdleMinutes());
+            }
+        }
+
+        /**
+         * Builds the resulting {@link KubernetesSlave} instance.
+         * @return an initialized {@link KubernetesSlave} instance.
+         * @throws IOException
+         * @throws Descriptor.FormException
+         */
+        public KubernetesSlave build() throws IOException, Descriptor.FormException {
+            Validate.notNull(podTemplate);
+            Validate.notNull(cloud);
+            return new KubernetesSlave(
+                    name == null ? getSlaveName(podTemplate) : name,
+                    podTemplate,
+                    nodeDescription == null ? podTemplate.getName() : nodeDescription,
+                    cloud.name,
+                    label == null ? podTemplate.getLabel() : label,
+                    computerLauncher == null ? new KubernetesLauncher() : computerLauncher,
+                    retentionStrategy == null ? determineRetentionStrategy() : retentionStrategy);
+        }
+    }
+
+
     @Extension
     public static final class DescriptorImpl extends SlaveDescriptor {
 

src/main/java/org/csanchez/jenkins/plugins/kubernetes/PlannedNodeBuilder.java

@@ -0,0 +1,81 @@
+package org.csanchez.jenkins.plugins.kubernetes;
+
+import hudson.model.Label;
+import hudson.slaves.NodeProvisioner;
+
+/**
+ * A builder of {@link hudson.slaves.NodeProvisioner.PlannedNode} implementations for Kubernetes.
+ * Can be subclassed to provide alternative implementations of {@link hudson.slaves.NodeProvisioner.PlannedNode}.
+ */
+public abstract class PlannedNodeBuilder {
+    private KubernetesCloud cloud;
+    private PodTemplate template;
+    private Label label;
+    private int numExecutors = 1;
+
+    /**
+     * Returns the {@link KubernetesCloud}.
+     * @return the {@link KubernetesCloud}.
+     */
+    public KubernetesCloud getCloud() {
+        return cloud;
+    }
+
+    /**
+     * Returns the {@link PodTemplate}.
+     * @return
+     */
+    public PodTemplate getTemplate() {
+        return template;
+    }
+
+    public Label getLabel() {
+        return label;
+    }
+
+    public int getNumExecutors() {
+        return numExecutors;
+    }
+
+    /**
+     * @param cloud the {@link KubernetesCloud} instance to use.
+     * @return the current builder.
+     */
+    public PlannedNodeBuilder cloud(KubernetesCloud cloud) {
+        this.cloud = cloud;
+        return this;
+    }
+
+    /**
+     * @param template the {@link PodTemplate} instance to use.
+     * @return the current builder.
+     */
+    public PlannedNodeBuilder template(PodTemplate template) {
+        this.template = template;
+        return this;
+    }
+
+    /**
+     * @param label the {@link Label} to use.
+     * @return the current builder.
+     */
+    public PlannedNodeBuilder label(Label label) {
+        this.label = label;
+        return this;
+    }
+
+    /**
+     * @param numExecutors the number of executors.
+     * @return the current builder.
+     */
+    public PlannedNodeBuilder numExecutors(int numExecutors) {
+        this.numExecutors = numExecutors;
+        return this;
+    }
+
+    /**
+     * Builds the {@link hudson.slaves.NodeProvisioner.PlannedNode} instance based on the given inputs.
+     * @return a {@link hudson.slaves.NodeProvisioner.PlannedNode} configured from this builder.
+     */
+    public abstract NodeProvisioner.PlannedNode build();
+}

src/main/java/org/csanchez/jenkins/plugins/kubernetes/PlannedNodeBuilderFactory.java

@@ -0,0 +1,37 @@
+package org.csanchez.jenkins.plugins.kubernetes;
+
+import hudson.ExtensionList;
+import hudson.ExtensionPoint;
+
+/**
+ * A factory of {@link PlannedNodeBuilder} instances.
+ */
+public abstract class PlannedNodeBuilderFactory implements ExtensionPoint {
+    /**
+     * Returns all registered implementations of {@link PlannedNodeBuilderFactory}.
+     * @return all registered implementations of {@link PlannedNodeBuilderFactory}.
+     */
+    public static ExtensionList<PlannedNodeBuilderFactory> all() {
+        return ExtensionList.lookup(PlannedNodeBuilderFactory.class);
+    }
+
+    /**
+     * Returns a new instance of {@link PlannedNodeBuilder}.
+     * @return a new instance of {@link PlannedNodeBuilder}.
+     */
+    public static PlannedNodeBuilder createInstance() {
+        for (PlannedNodeBuilderFactory factory: all()) {
+            PlannedNodeBuilder plannedNodeBuilder = factory.newInstance();
+            if (plannedNodeBuilder != null) {
+                return plannedNodeBuilder;
+            }
+        }
+        return new StandardPlannedNodeBuilder();
+    }
+
+    /**
+     * Creates a new instance of {@link PlannedNodeBuilder}.
+     * @return a new instance of {@link PlannedNodeBuilder}.
+     */
+    public abstract PlannedNodeBuilder newInstance();
+}