Add License headers, refactor nested try

Author: Marcus Sorensen

core/src/main/java/com/cloud/resource/AgentStatusUpdater.java

@@ -1,5 +1,27 @@
+// Licensed to the Apache Software Foundation (ASF) under one
+// or more contributor license agreements.  See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership.  The ASF licenses this file
+// to you under the Apache License, Version 2.0 (the
+// "License"); you may not use this file except in compliance
+// with the License.  You may obtain a copy of the License at
+//
+//   http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing,
+// software distributed under the License is distributed on an
+// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+// KIND, either express or implied.  See the License for the
+// specific language governing permissions and limitations
+// under the License.
 package com.cloud.resource;
 
+/**
+ * AgentStatusUpdater is an agent with triggerable update functionality
+ */
 public interface AgentStatusUpdater {
+    /**
+     * Trigger the sending of an update (Ping).
+     */
     void triggerUpdate();
 }

core/src/main/java/com/cloud/resource/ResourceStatusUpdater.java

@@ -1,10 +1,28 @@
+// Licensed to the Apache Software Foundation (ASF) under one
+// or more contributor license agreements.  See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership.  The ASF licenses this file
+// to you under the Apache License, Version 2.0 (the
+// "License"); you may not use this file except in compliance
+// with the License.  You may obtain a copy of the License at
+//
+//   http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing,
+// software distributed under the License is distributed on an
+// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+// KIND, either express or implied.  See the License for the
+// specific language governing permissions and limitations
+// under the License.
 package com.cloud.resource;
 
 /**
  * ResourceStatusUpdater is a resource that can trigger out of band status updates
  */
 public interface ResourceStatusUpdater {
     /**
+     * Register an AgentStatusUpdater to use for triggering out of band updates.
+     *
      * @param updater The object to call triggerUpdate() on
      */
     void registerStatusUpdater(AgentStatusUpdater updater);

plugins/hypervisors/kvm/src/main/java/com/cloud/hypervisor/kvm/resource/LibvirtComputingResource.java

@@ -91,6 +91,7 @@
 import org.libvirt.SchedUlongParameter;
 import org.libvirt.Secret;
 import org.libvirt.VcpuInfo;
+import org.libvirt.event.DomainEvent;
 import org.libvirt.event.DomainEventDetail;
 import org.libvirt.event.StoppedDetail;
 import org.w3c.dom.Document;
@@ -3608,55 +3609,58 @@ private StartupStorageCommand createLocalStoragePool(String localStoragePath, St
     }
 
     private void setupLibvirtEventListener() {
+        final Thread libvirtListenerThread = new Thread(() -> {
+            try {
+                Library.runEventLoop();
+            } catch (LibvirtException e) {
+                s_logger.error("LibvirtException was thrown in event loop: ", e);
+            } catch (InterruptedException e) {
+                s_logger.error("Libvirt event loop was interrupted: ", e);
+            }
+        });
+
         try {
-            final Thread t = new Thread(() -> {
-                try {
-                    Library.runEventLoop();
-                } catch (LibvirtException e) {
-                    s_logger.error("LibvirtException was thrown in event loop: ", e);
-                } catch (InterruptedException e) {
-                    s_logger.error("Libvirt event loop was interrupted: ", e);
-                }
-            });
-            t.setDaemon(true);
-            t.start();
+            libvirtListenerThread.setDaemon(true);
+            libvirtListenerThread.start();
 
             Connect conn = LibvirtConnection.getConnection();
-            conn.addLifecycleListener((domain, domainEvent) -> {
-                try {
-                    s_logger.debug(String.format("Got event lifecycle change on Domain %s, event %s", domain.getName(), domainEvent));
-                    if (domainEvent != null) {
-                        switch (domainEvent.getType()) {
-                            case STOPPED:
-                                /* libvirt-destroyed VMs have detail StoppedDetail.DESTROYED, self shutdown guests are StoppedDetail.SHUTDOWN
-                                * Checking for this helps us differentiate between events where cloudstack or admin stopped the VM vs guest
-                                * initiated, and avoid pushing extra updates for actions we are initiating without a need for extra tracking */
-                                DomainEventDetail detail = domainEvent.getDetail();
-                                if (StoppedDetail.SHUTDOWN.equals(detail) || StoppedDetail.CRASHED.equals(detail)) {
-                                    s_logger.info("Triggering out of band status update due to completed self-shutdown or crash of VM");
-                                    _agentStatusUpdater.triggerUpdate();
-                                } else {
-                                    s_logger.debug("Event detail: " + detail);
-                                }
-                                break;
-                            default:
-                                s_logger.debug(String.format("No handling for event %s", domainEvent));
-                        }
-                    }
-                } catch (LibvirtException e) {
-                    s_logger.error("Libvirt exception while processing lifecycle event", e);
-                } catch (Throwable e) {
-                    s_logger.error("Error during lifecycle", e);
-                }
-                return 0;
-            });
+            conn.addLifecycleListener(this::onDomainLifecycleChange);
 
             s_logger.debug("Set up the libvirt domain event lifecycle listener");
         } catch (LibvirtException e) {
             s_logger.error("Failed to get libvirt connection for domain event lifecycle", e);
         }
     }
 
+    private int onDomainLifecycleChange(Domain domain, DomainEvent domainEvent) {
+        try {
+            s_logger.debug(String.format("Got event lifecycle change on Domain %s, event %s", domain.getName(), domainEvent));
+            if (domainEvent != null) {
+                switch (domainEvent.getType()) {
+                    case STOPPED:
+                        /* libvirt-destroyed VMs have detail StoppedDetail.DESTROYED, self shutdown guests are StoppedDetail.SHUTDOWN
+                         * Checking for this helps us differentiate between events where cloudstack or admin stopped the VM vs guest
+                         * initiated, and avoid pushing extra updates for actions we are initiating without a need for extra tracking */
+                        DomainEventDetail detail = domainEvent.getDetail();
+                        if (StoppedDetail.SHUTDOWN.equals(detail) || StoppedDetail.CRASHED.equals(detail)) {
+                            s_logger.info("Triggering out of band status update due to completed self-shutdown or crash of VM");
+                            _agentStatusUpdater.triggerUpdate();
+                        } else {
+                            s_logger.debug("Event detail: " + detail);
+                        }
+                        break;
+                    default:
+                        s_logger.debug(String.format("No handling for event %s", domainEvent));
+                }
+            }
+        } catch (LibvirtException e) {
+            s_logger.error("Libvirt exception while processing lifecycle event", e);
+        } catch (Throwable e) {
+            s_logger.error("Error during lifecycle", e);
+        }
+        return 0;
+    }
+
     public String diskUuidToSerial(String uuid) {
         String uuidWithoutHyphen = uuid.replace("-","");
         return uuidWithoutHyphen.substring(0, Math.min(uuidWithoutHyphen.length(), 20));