From 98b46d48fefc7801b7c9e496000e9329f4266e5e Mon Sep 17 00:00:00 2001
From: Justin Clark-Casey (justincc)
Date: Thu, 7 Jun 2012 02:44:13 +0100
Subject: Allow the thread watchdog to accept an alarm method that is invoked
 if the timeout is breached.

This alarm can then invoke this to log extra information.
This is used in LLUDPServer to show which client was being processed when incoming and outgoing udp watchdog alarms are triggered.
---
 OpenSim/Framework/Watchdog.cs | 40 +++++++++++++++++++++++-----------------
 1 file changed, 23 insertions(+), 17 deletions(-)

(limited to 'OpenSim/Framework/Watchdog.cs')

diff --git a/OpenSim/Framework/Watchdog.cs b/OpenSim/Framework/Watchdog.cs
index e93e50e..7552cd1 100644
--- a/OpenSim/Framework/Watchdog.cs
+++ b/OpenSim/Framework/Watchdog.cs
@@ -42,7 +42,7 @@ namespace OpenSim.Framework
         const double WATCHDOG_INTERVAL_MS = 2500.0d;
 
         /// <summary>Maximum timeout in milliseconds before a thread is considered dead</summary>
-        const int WATCHDOG_TIMEOUT_MS = 5000;
+        public const int WATCHDOG_TIMEOUT_MS = 5000;
 
         [System.Diagnostics.DebuggerDisplay("{Thread.Name}")]
         public class ThreadWatchdogInfo
@@ -58,7 +58,7 @@ namespace OpenSim.Framework
             public int FirstTick { get; private set; }
 
             /// <summary>
-            /// First time this heartbeat update was invoked
+            /// Last time this heartbeat update was invoked
             /// </summary>
             public int LastTick { get; set; }
 
@@ -77,6 +77,11 @@ namespace OpenSim.Framework
             /// </summary>
             public bool AlarmIfTimeout { get; set; }
 
+            /// <summary>
+            /// Method execute if alarm goes off.  If null then no alarm method is fired.
+            /// </summary>
+            public Func<string> AlarmMethod { get; set; }
+
             public ThreadWatchdogInfo(Thread thread, int timeout)
             {
                 Thread = thread;
@@ -87,16 +92,10 @@ namespace OpenSim.Framework
         }
 
         /// <summary>
-        /// This event is called whenever a tracked thread is stopped or
-        /// has not called UpdateThread() in time
-        /// </summary>
-        /// <param name="thread">The thread that has been identified as dead</param>
-        /// <param name="lastTick">The last time this thread called UpdateThread()</param>
-        public delegate void WatchdogTimeout(Thread thread, int lastTick);
-
-        /// <summary>This event is called whenever a tracked thread is
-        /// stopped or has not called UpdateThread() in time</summary>
-        public static event WatchdogTimeout OnWatchdogTimeout;
+        /// This event is called whenever a tracked thread is
+        /// stopped or has not called UpdateThread() in time<
+        /// /summary>
+        public static event Action<ThreadWatchdogInfo> OnWatchdogTimeout;
 
         private static readonly ILog m_log = LogManager.GetLogger(System.Reflection.MethodBase.GetCurrentMethod().DeclaringType);
         private static Dictionary<int, ThreadWatchdogInfo> m_threads;
@@ -123,7 +122,7 @@ namespace OpenSim.Framework
         public static Thread StartThread(
             ThreadStart start, string name, ThreadPriority priority, bool isBackground, bool alarmIfTimeout)
         {
-            return StartThread(start, name, priority, isBackground, alarmIfTimeout, WATCHDOG_TIMEOUT_MS);
+            return StartThread(start, name, priority, isBackground, alarmIfTimeout, null, WATCHDOG_TIMEOUT_MS);
         }
 
         /// <summary>
@@ -135,17 +134,24 @@ namespace OpenSim.Framework
         /// <param name="isBackground">True to run this thread as a background
         /// thread, otherwise false</param>
         /// <param name="alarmIfTimeout">Trigger an alarm function is we have timed out</param>
+        /// <param name="alarmMethod">
+        /// Alarm method to call if alarmIfTimeout is true and there is a timeout.
+        /// Normally, this will just return some useful debugging information.
+        /// </param>
         /// <param name="timeout">Number of milliseconds to wait until we issue a warning about timeout.</param>
         /// <returns>The newly created Thread object</returns>
         public static Thread StartThread(
-            ThreadStart start, string name, ThreadPriority priority, bool isBackground, bool alarmIfTimeout, int timeout)
+            ThreadStart start, string name, ThreadPriority priority, bool isBackground,
+            bool alarmIfTimeout, Func<string> alarmMethod, int timeout)
         {
             Thread thread = new Thread(start);
             thread.Name = name;
             thread.Priority = priority;
             thread.IsBackground = isBackground;
             
-            ThreadWatchdogInfo twi = new ThreadWatchdogInfo(thread, timeout) { AlarmIfTimeout = alarmIfTimeout };
+            ThreadWatchdogInfo twi
+                = new ThreadWatchdogInfo(thread, timeout)
+                    { AlarmIfTimeout = alarmIfTimeout, AlarmMethod = alarmMethod };
 
             m_log.DebugFormat(
                 "[WATCHDOG]: Started tracking thread {0}, ID {1}", twi.Thread.Name, twi.Thread.ManagedThreadId);
@@ -258,7 +264,7 @@ namespace OpenSim.Framework
         /// <param name="e"></param>
         private static void WatchdogTimerElapsed(object sender, System.Timers.ElapsedEventArgs e)
         {
-            WatchdogTimeout callback = OnWatchdogTimeout;
+            Action<ThreadWatchdogInfo> callback = OnWatchdogTimeout;
 
             if (callback != null)
             {
@@ -296,7 +302,7 @@ namespace OpenSim.Framework
 
                 if (callbackInfos != null)
                     foreach (ThreadWatchdogInfo callbackInfo in callbackInfos)
-                        callback(callbackInfo.Thread, callbackInfo.LastTick);
+                        callback(callbackInfo);
             }
 
             m_watchdogTimer.Start();
-- 
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