Initialize reaper when launching a kubernetes agent

Author: Vlatombe

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

@@ -48,6 +48,7 @@
 import java.util.stream.Collectors;
 import jenkins.metrics.api.Metrics;
 import org.apache.commons.lang.StringUtils;
+import org.csanchez.jenkins.plugins.kubernetes.pod.retention.Reaper;
 import org.kohsuke.stapler.DataBoundConstructor;
 
 import static java.util.logging.Level.FINE;
@@ -94,6 +95,8 @@ public synchronized void launch(SlaveComputer computer, TaskListener listener) {
         if (!(computer instanceof KubernetesComputer)) {
             throw new IllegalArgumentException("This Launcher can be used only with KubernetesComputer");
         }
+        // Activate reaper if it never got activated.
+        Reaper.getInstance().maybeActivate();
         KubernetesComputer kubernetesComputer = (KubernetesComputer) computer;
         computer.setAcceptingTasks(false);
         KubernetesSlave node = kubernetesComputer.getNode();

src/main/java/org/csanchez/jenkins/plugins/kubernetes/pod/retention/Reaper.java

@@ -92,12 +92,18 @@ public static Reaper getInstance() {
 
     @Override
     public void onOnline(Computer c, TaskListener listener) throws IOException, InterruptedException {
-        if (c instanceof KubernetesComputer && activated.compareAndSet(false, true)) {
+        if (c instanceof KubernetesComputer) {
+            maybeActivate();
+        }
+    }
+
+    public void maybeActivate() {
+        if (activated.compareAndSet(false, true)) {
             activate();
         }
     }
 
-    private void activate() {
+    private synchronized void activate() {
         LOGGER.fine("Activating reaper");
         // First check all existing nodes to see if they still have active pods.
         // (We may have missed deletion events while Jenkins was shut off,

src/test/java/org/csanchez/jenkins/plugins/kubernetes/pipeline/KubernetesPipelineTest.java

@@ -701,6 +701,12 @@ public void invalidPodGetsCancelled() throws Exception {
         r.assertLogContains("Queue task was cancelled", b);
     }
 
+    @Test
+    public void invalidImageGetsCancelled() throws Exception {
+        r.assertBuildStatus(Result.ABORTED, r.waitForCompletion(b));
+        r.assertLogContains("Queue task was cancelled", b);
+    }
+
     @Issue("SECURITY-1646")
     @Test
     public void substituteEnv() throws Exception {

src/test/resources/org/csanchez/jenkins/plugins/kubernetes/pipeline/invalidImageGetsCancelled.groovy

@@ -0,0 +1,10 @@
+podTemplate(yaml: '''
+spec:
+  containers:
+  - name: jnlp
+    image: some/invalid
+''') {
+  node(POD_LABEL) {
+    sh 'This will never run'
+  }
+}