From 9d71b491bb9ad8b14f6a3bea7269f879812373dd Mon Sep 17 00:00:00 2001
From: Asad Ahmed <asaahmed@cisco.com>
Date: Wed, 5 Feb 2014 15:44:31 -0800
Subject: [PATCH] The Switch Event thread is the thread that processes events
 coming from all switches. Right now its very fragile as an unhandled
 exception can cause the thread to die causing the controller to be unusable.
 Making the thread more tolerant of exceptions and making the shutdown of the
 thread more deterministic.

Change-Id: I31c31f012229de8e124c0c13fa651513daaf6776
Signed-off-by: Asad Ahmed <asaahmed@cisco.com>
---
 .../openflow/core/internal/Controller.java       | 16 +++++++++++++---
 1 file changed, 13 insertions(+), 3 deletions(-)

diff --git a/opendaylight/protocol_plugins/openflow/src/main/java/org/opendaylight/controller/protocol_plugin/openflow/core/internal/Controller.java b/opendaylight/protocol_plugins/openflow/src/main/java/org/opendaylight/controller/protocol_plugin/openflow/core/internal/Controller.java
index 72ee7a679b..63dd0bc29a 100644
--- a/opendaylight/protocol_plugins/openflow/src/main/java/org/opendaylight/controller/protocol_plugin/openflow/core/internal/Controller.java
+++ b/opendaylight/protocol_plugins/openflow/src/main/java/org/opendaylight/controller/protocol_plugin/openflow/core/internal/Controller.java
@@ -48,6 +48,7 @@ public class Controller implements IController, CommandProvider, IPluginInConnec
             .getLogger(Controller.class);
     private ControllerIO controllerIO;
     private Thread switchEventThread;
+    private volatile boolean shutdownSwitchEventThread;// default to false
     private ConcurrentHashMap<Long, ISwitch> switches;
     private PriorityBlockingQueue<SwitchEvent> switchEvents;
     // only 1 message listener per OFType
@@ -69,6 +70,12 @@ public class Controller implements IController, CommandProvider, IPluginInConnec
 
             while (true) {
                 try {
+                    if(shutdownSwitchEventThread) {
+                        // break out of the infinite loop
+                        // if you are shutting down
+                        logger.info("Switch Event Thread is shutting down");
+                        break;
+                    }
                     SwitchEvent ev = switchEvents.take();
                     SwitchEvent.SwitchEventType eType = ev.getEventType();
                     ISwitch sw = ev.getSwitch();
@@ -104,12 +111,14 @@ public class Controller implements IController, CommandProvider, IPluginInConnec
                         logger.error("Unknown switch event {}", eType.ordinal());
                     }
                 } catch (InterruptedException e) {
-                    switchEvents.clear();
-                    return;
+                    // nothing to do except retry
+                } catch (Exception e) {
+                    // log the exception and retry
+                    logger.warn("Exception in Switch Event Thread is {}" ,e);
                 }
             }
+            switchEvents.clear();
         }
-
     }
 
     /**
@@ -167,6 +176,7 @@ public class Controller implements IController, CommandProvider, IPluginInConnec
             ((SwitchHandler) entry.getValue()).stop();
             it.remove();
         }
+        shutdownSwitchEventThread = true;
         switchEventThread.interrupt();
         try {
             controllerIO.shutDown();
-- 
2.36.6