Fix ONOS-4683 - Don't process device events on the listener thread

Change-Id: Icc465311c2c047dba11bacc69c745bbda55ea714

@@ -15,9 +15,16 @@
  */
 package org.onosproject.provider.lldp.impl;
 
-import com.google.common.collect.ImmutableMap;
-import com.google.common.collect.ImmutableSet;
-import com.google.common.collect.Maps;
+import java.util.Dictionary;
+import java.util.EnumSet;
+import java.util.Map;
+import java.util.Optional;
+import java.util.Properties;
+import java.util.Set;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.ScheduledExecutorService;
+
 import org.apache.felix.scr.annotations.Activate;
 import org.apache.felix.scr.annotations.Component;
 import org.apache.felix.scr.annotations.Deactivate;
@@ -26,7 +33,6 @@ import org.apache.felix.scr.annotations.Property;
 import org.apache.felix.scr.annotations.Reference;
 import org.apache.felix.scr.annotations.ReferenceCardinality;
 import org.onlab.packet.Ethernet;
-import org.onlab.util.SharedExecutors;
 import org.onlab.util.Tools;
 import org.onosproject.cfg.ComponentConfigService;
 import org.onosproject.cluster.ClusterMetadataService;
@@ -52,30 +58,25 @@ import org.onosproject.net.device.DeviceService;
 import org.onosproject.net.flow.DefaultTrafficSelector;
 import org.onosproject.net.flow.TrafficSelector;
 import org.onosproject.net.link.DefaultLinkDescription;
-import org.onosproject.net.link.ProbedLinkProvider;
 import org.onosproject.net.link.LinkProviderRegistry;
 import org.onosproject.net.link.LinkProviderService;
 import org.onosproject.net.link.LinkService;
+import org.onosproject.net.link.ProbedLinkProvider;
 import org.onosproject.net.packet.PacketContext;
 import org.onosproject.net.packet.PacketPriority;
 import org.onosproject.net.packet.PacketProcessor;
 import org.onosproject.net.packet.PacketService;
 import org.onosproject.net.provider.AbstractProvider;
 import org.onosproject.net.provider.ProviderId;
-import org.onosproject.provider.lldpcommon.LinkDiscoveryContext;
 import org.onosproject.provider.lldpcommon.LinkDiscovery;
+import org.onosproject.provider.lldpcommon.LinkDiscoveryContext;
 import org.onosproject.store.service.ConsistentMapException;
 import org.osgi.service.component.ComponentContext;
 import org.slf4j.Logger;
 
-import java.util.Dictionary;
-import java.util.EnumSet;
-import java.util.Map;
-import java.util.Optional;
-import java.util.Properties;
-import java.util.Set;
-import java.util.concurrent.ConcurrentHashMap;
-import java.util.concurrent.ScheduledExecutorService;
+import com.google.common.collect.ImmutableMap;
+import com.google.common.collect.ImmutableSet;
+import com.google.common.collect.Maps;
 
 import static com.google.common.base.Strings.isNullOrEmpty;
 import static java.util.concurrent.Executors.newSingleThreadScheduledExecutor;
@@ -143,6 +144,7 @@ public class LldpLinkProvider extends AbstractProvider implements ProbedLinkProv
     private LinkProviderService providerService;
 
     private ScheduledExecutorService executor;
+    protected ExecutorService eventExecutor;
 
     private boolean shuttingDown = false;
 
@@ -242,6 +244,7 @@ public class LldpLinkProvider extends AbstractProvider implements ProbedLinkProv
 
     @Activate
     public void activate(ComponentContext context) {
+        eventExecutor = newSingleThreadScheduledExecutor(groupedThreads("onos/linkevents", "events-%d", log));
         shuttingDown = false;
         cfgService.registerProperties(getClass());
         appId = coreService.registerApplication(PROVIDER_NAME);
@@ -280,6 +283,8 @@ public class LldpLinkProvider extends AbstractProvider implements ProbedLinkProv
 
         cfgService.unregisterProperties(getClass(), false);
         disable();
+        eventExecutor.shutdownNow();
+        eventExecutor = null;
         log.info("Stopped");
     }
 
@@ -548,6 +553,7 @@ public class LldpLinkProvider extends AbstractProvider implements ProbedLinkProv
                 return;
             }
 
+            eventExecutor.execute(() -> {
                 DeviceId deviceId = event.subject();
                 Device device = deviceService.getDevice(deviceId);
                 if (device == null) {
@@ -557,18 +563,20 @@ public class LldpLinkProvider extends AbstractProvider implements ProbedLinkProv
                 if (clusterService.getLocalNode().id().equals(event.roleInfo().master())) {
                     updateDevice(device).ifPresent(ld -> updatePorts(ld, device.id()));
                 }
+            });
         }
     }
 
-    /**
-     * Processes device events.
-     */
-    private class InternalDeviceListener implements DeviceListener {
-        @Override
-        public void event(DeviceEvent event) {
-            if (event.type() == Type.PORT_STATS_UPDATED) {
-                return;
+    private class DeviceEventProcessor implements Runnable {
+
+        DeviceEvent event;
+
+        DeviceEventProcessor(DeviceEvent event) {
+            this.event = event;
         }
+
+        @Override
+        public void run() {
             Device device = event.subject();
             Port port = event.port();
             if (device == null) {
@@ -624,6 +632,22 @@ public class LldpLinkProvider extends AbstractProvider implements ProbedLinkProv
     }
 
     /**
+     * Processes device events.
+     */
+    private class InternalDeviceListener implements DeviceListener {
+        @Override
+        public void event(DeviceEvent event) {
+            if (event.type() == Type.PORT_STATS_UPDATED) {
+                return;
+            }
+
+            Runnable deviceEventProcessor = new DeviceEventProcessor(event);
+
+            eventExecutor.execute(deviceEventProcessor);
+        }
+    }
+
+    /**
      * Processes incoming packets.
      */
     private class InternalPacketProcessor implements PacketProcessor {
@@ -780,7 +804,7 @@ public class LldpLinkProvider extends AbstractProvider implements ProbedLinkProv
 
         @Override
         public void event(NetworkConfigEvent event) {
-            SharedExecutors.getPoolThreadExecutor().execute(() -> {
+            eventExecutor.execute(() -> {
                 if (event.configClass() == LinkDiscoveryFromDevice.class &&
                         CONFIG_CHANGED.contains(event.type())) {
 

@@ -75,6 +75,7 @@ import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableMap;
 import com.google.common.collect.ImmutableSet;
 import com.google.common.collect.Lists;
+import com.google.common.util.concurrent.MoreExecutors;
 
 import static org.easymock.EasyMock.createMock;
 import static org.easymock.EasyMock.expect;
@@ -147,6 +148,8 @@ public class LldpLinkProviderTest {
 
         provider.activate(null);
 
+        provider.eventExecutor = MoreExecutors.newDirectExecutorService();
+
         providerService = linkRegistry.registeredProvider();
     }
 

@@ -255,6 +255,9 @@ public class LinkDiscovery implements TimerTask {
     }
 
     private void sendProbes(Long portNumber) {
+        if (context.packetService() == null) {
+            return;
+        }
         log.trace("Sending probes out to {}@{}", portNumber, device.id());
         OutboundPacket pkt = createOutBoundLldp(portNumber);
         context.packetService().emit(pkt);