From d607b831c98253150308c31dd8cf697fc5d2194c Mon Sep 17 00:00:00 2001
From: "kay.one" <kay.one@gmail.com>
Date: Thu, 11 Jul 2013 23:10:34 -0700
Subject: [PATCH] added exception logging to Tasks.

---
 .../Messaging/MessageAggregator.cs            |  4 ++-
 NzbDrone.Common/NzbDrone.Common.csproj        |  3 ++-
 .../LimitedConcurrencyLevelTaskScheduler.cs   |  2 +-
 NzbDrone.Common/TPL/TaskExtensions.cs         | 25 +++++++++++++++++++
 .../IndexerSearch/NzbSearchService.cs         |  3 ++-
 .../Indexers/FetchAndParseRssService.cs       |  3 ++-
 NzbDrone.Core/Jobs/Scheduler.cs               |  5 +++-
 7 files changed, 39 insertions(+), 6 deletions(-)
 rename NzbDrone.Common/{Messaging => TPL}/LimitedConcurrencyLevelTaskScheduler.cs (99%)
 create mode 100644 NzbDrone.Common/TPL/TaskExtensions.cs

diff --git a/NzbDrone.Common/Messaging/MessageAggregator.cs b/NzbDrone.Common/Messaging/MessageAggregator.cs
index 73f9eb335..5e73c5a4b 100644
--- a/NzbDrone.Common/Messaging/MessageAggregator.cs
+++ b/NzbDrone.Common/Messaging/MessageAggregator.cs
@@ -4,6 +4,7 @@
 using NLog;
 using NzbDrone.Common.EnsureThat;
 using NzbDrone.Common.Serializer;
+using NzbDrone.Common.TPL;
 
 namespace NzbDrone.Common.Messaging
 {
@@ -53,7 +54,8 @@ public void PublishEvent<TEvent>(TEvent @event) where TEvent : class ,IEvent
                     _logger.Debug("{0} ~> {1}", eventName, handlerLocal.GetType().Name);
                     handlerLocal.HandleAsync(@event);
                     _logger.Debug("{0} <~ {1}", eventName, handlerLocal.GetType().Name);
-                }, TaskCreationOptions.PreferFairness);
+                }, TaskCreationOptions.PreferFairness)
+                .LogExceptions();
             }
         }
 
diff --git a/NzbDrone.Common/NzbDrone.Common.csproj b/NzbDrone.Common/NzbDrone.Common.csproj
index 85eaa84e2..8c2b2a689 100644
--- a/NzbDrone.Common/NzbDrone.Common.csproj
+++ b/NzbDrone.Common/NzbDrone.Common.csproj
@@ -110,7 +110,7 @@
     <Compile Include="Exceptions\NzbDroneException.cs" />
     <Compile Include="Instrumentation\GlobalExceptionHandlers.cs" />
     <Compile Include="Instrumentation\ExceptronTarget.cs" />
-    <Compile Include="Messaging\LimitedConcurrencyLevelTaskScheduler.cs" />
+    <Compile Include="TPL\LimitedConcurrencyLevelTaskScheduler.cs" />
     <Compile Include="Security\IgnoreCertErrorPolicy.cs" />
     <Compile Include="StringExtensions.cs" />
     <Compile Include="EnsureThat\TypeParam.cs" />
@@ -160,6 +160,7 @@
     <Compile Include="RestProvider.cs" />
     <Compile Include="ServiceProvider.cs" />
     <Compile Include="TinyIoC.cs" />
+    <Compile Include="TPL\TaskExtensions.cs" />
     <Compile Include="TryParseExtension.cs" />
   </ItemGroup>
   <ItemGroup>
diff --git a/NzbDrone.Common/Messaging/LimitedConcurrencyLevelTaskScheduler.cs b/NzbDrone.Common/TPL/LimitedConcurrencyLevelTaskScheduler.cs
similarity index 99%
rename from NzbDrone.Common/Messaging/LimitedConcurrencyLevelTaskScheduler.cs
rename to NzbDrone.Common/TPL/LimitedConcurrencyLevelTaskScheduler.cs
index a8d9238ab..bc17dcc95 100644
--- a/NzbDrone.Common/Messaging/LimitedConcurrencyLevelTaskScheduler.cs
+++ b/NzbDrone.Common/TPL/LimitedConcurrencyLevelTaskScheduler.cs
@@ -4,7 +4,7 @@
 using System.Threading;
 using System.Threading.Tasks;
 
-namespace NzbDrone.Common.Messaging
+namespace NzbDrone.Common.TPL
 {
     public class LimitedConcurrencyLevelTaskScheduler : TaskScheduler
     {
diff --git a/NzbDrone.Common/TPL/TaskExtensions.cs b/NzbDrone.Common/TPL/TaskExtensions.cs
new file mode 100644
index 000000000..e655ac86f
--- /dev/null
+++ b/NzbDrone.Common/TPL/TaskExtensions.cs
@@ -0,0 +1,25 @@
+using System.Threading.Tasks;
+using NLog;
+
+namespace NzbDrone.Common.TPL
+{
+    public static class TaskExtensions
+    {
+        private static readonly Logger Logger = LogManager.GetLogger("TaskExtensions");
+
+        public static Task LogExceptions(this Task task)
+        {
+            task.ContinueWith(t =>
+                {
+                    var aggregateException = t.Exception.Flatten();
+                    foreach (var exception in aggregateException.InnerExceptions)
+                    {
+                        Logger.ErrorException("Task Error", exception);
+                    }
+
+                }, TaskContinuationOptions.OnlyOnFaulted);
+
+            return task;
+        }
+    }
+}
\ No newline at end of file
diff --git a/NzbDrone.Core/IndexerSearch/NzbSearchService.cs b/NzbDrone.Core/IndexerSearch/NzbSearchService.cs
index e3f434c7a..2144986be 100644
--- a/NzbDrone.Core/IndexerSearch/NzbSearchService.cs
+++ b/NzbDrone.Core/IndexerSearch/NzbSearchService.cs
@@ -9,6 +9,7 @@
 using NzbDrone.Core.Parser.Model;
 using NzbDrone.Core.Tv;
 using System.Linq;
+using NzbDrone.Common.TPL;
 
 namespace NzbDrone.Core.IndexerSearch
 {
@@ -158,7 +159,7 @@ private List<DownloadDecision> Dispatch(Func<IIndexer, IEnumerable<ReportInfo>>
                     {
                         _logger.ErrorException("Error while searching for " + criteriaBase, e);
                     }
-                }));
+                }).LogExceptions());
             }
 
             Task.WaitAll(taskList.ToArray());
diff --git a/NzbDrone.Core/Indexers/FetchAndParseRssService.cs b/NzbDrone.Core/Indexers/FetchAndParseRssService.cs
index 5eef13992..9ee704910 100644
--- a/NzbDrone.Core/Indexers/FetchAndParseRssService.cs
+++ b/NzbDrone.Core/Indexers/FetchAndParseRssService.cs
@@ -3,6 +3,7 @@
 using System.Threading.Tasks;
 using NLog;
 using NzbDrone.Core.Parser.Model;
+using NzbDrone.Common.TPL;
 
 namespace NzbDrone.Core.Indexers
 {
@@ -54,7 +55,7 @@ public List<ReportInfo> Fetch()
                          {
                              result.AddRange(indexerFeed);
                          }
-                     });
+                     }).LogExceptions();
 
                 taskList.Add(task);
             }
diff --git a/NzbDrone.Core/Jobs/Scheduler.cs b/NzbDrone.Core/Jobs/Scheduler.cs
index 0fe50bcaf..f294c74a6 100644
--- a/NzbDrone.Core/Jobs/Scheduler.cs
+++ b/NzbDrone.Core/Jobs/Scheduler.cs
@@ -6,6 +6,7 @@
 using NzbDrone.Common.Messaging;
 using NzbDrone.Core.Lifecycle;
 using Timer = System.Timers.Timer;
+using NzbDrone.Common.TPL;
 
 namespace NzbDrone.Core.Jobs
 {
@@ -30,7 +31,9 @@ public void Handle(ApplicationStartedEvent message)
         {
             _cancellationTokenSource = new CancellationTokenSource();
             Timer.Interval = 1000 * 30;
-            Timer.Elapsed += (o, args) => Task.Factory.StartNew(ExecuteCommands, _cancellationTokenSource.Token);
+            Timer.Elapsed += (o, args) => Task.Factory.StartNew(ExecuteCommands, _cancellationTokenSource.Token)
+                .LogExceptions();
+            
             Timer.Start();
         }