From 857979135f580cedfccc935cada2b1e372f56c92 Mon Sep 17 00:00:00 2001
From: yvesgoeleven <yves@goeleven.com>
Date: Wed, 6 Feb 2013 09:07:47 +0100
Subject: [PATCH] Fixed effects of concurrent delete on databus message expiry

---
 .../BlobStorageDataBus.cs                     | 65 ++++++++++++-------
 1 file changed, 40 insertions(+), 25 deletions(-)

diff --git a/src/azure/DataBus/NServiceBus.DataBus.Azure.BlobStorage/BlobStorageDataBus.cs b/src/azure/DataBus/NServiceBus.DataBus.Azure.BlobStorage/BlobStorageDataBus.cs
index eb80c1ddce8..340dd73807d 100644
--- a/src/azure/DataBus/NServiceBus.DataBus.Azure.BlobStorage/BlobStorageDataBus.cs
+++ b/src/azure/DataBus/NServiceBus.DataBus.Azure.BlobStorage/BlobStorageDataBus.cs
@@ -1,16 +1,16 @@
-using System;
-using System.Collections.Generic;
-using System.Globalization;
-using System.IO;
-using System.Linq;
-using System.Net;
-using System.Threading;
-using log4net;
-using Microsoft.WindowsAzure.StorageClient;
-using Microsoft.WindowsAzure.StorageClient.Protocol;
-
 namespace NServiceBus.DataBus.Azure.BlobStorage
 {
+    using System;
+    using System.Collections.Generic;
+    using System.Globalization;
+    using System.IO;
+    using System.Linq;
+    using System.Net;
+    using System.Threading;
+    using Microsoft.WindowsAzure.StorageClient;
+    using Microsoft.WindowsAzure.StorageClient.Protocol;
+    using log4net;
+
     public class BlobStorageDataBus : IDataBus
     {
         private readonly ILog logger = LogManager.GetLogger(typeof(IDataBus));
@@ -78,6 +78,10 @@ private void DeleteExpiredBlobs()
                         blockBlob.DeleteIfExists();
                 }
             }
+            catch (StorageClientException ex) // to handle race conditions between multiple active instances.
+            {
+                logger.Warn(ex.Message);
+            }
             catch (StorageServerException ex) // prevent azure hickups from hurting us.
             {
                 logger.Warn(ex.Message);
@@ -137,22 +141,33 @@ private void Commit(CloudBlockBlob blob, List<string> originalOrder)
 
         private void DownloadBlobInParallel(CloudBlob blob, Stream stream)
         {
-            blob.FetchAttributes();
-            var order = new List<string>();
-            var blocksToDownload = new Queue<Block>();
-            CalculateBlocks(blocksToDownload, (int)blob.Properties.Length, order);
-            ExecuteInParallel(() => AsLongAsThereAre(blocksToDownload, block =>
+            try
             {
-                var s = DownloadBlockFromBlob(blob, block, blocksToDownload); if (s == null) return;
-                var buffer = new byte[BlockSize];
-                ExtractBytesFromBlockIntoBuffer(buffer, s, block);
-                lock (stream)
+                blob.FetchAttributes();
+                var order = new List<string>();
+                var blocksToDownload = new Queue<Block>();
+                CalculateBlocks(blocksToDownload, (int)blob.Properties.Length, order);
+                ExecuteInParallel(() => AsLongAsThereAre(blocksToDownload, block =>
                 {
-                    stream.Position = block.Offset;
-                    stream.Write(buffer, 0,block.Length);
-                }
-            }));
-            stream.Seek(0, SeekOrigin.Begin);
+                    var s = DownloadBlockFromBlob(blob, block, blocksToDownload); if (s == null) return;
+                    var buffer = new byte[BlockSize];
+                    ExtractBytesFromBlockIntoBuffer(buffer, s, block);
+                    lock (stream)
+                    {
+                        stream.Position = block.Offset;
+                        stream.Write(buffer, 0,block.Length);
+                    }
+                }));
+                stream.Seek(0, SeekOrigin.Begin);
+            }
+            catch (StorageClientException ex) // to handle race conditions between multiple active instances.
+            {
+                logger.Warn(ex.Message);
+            }
+            catch (StorageServerException ex) // prevent azure hickups from hurting us.
+            {
+                logger.Warn(ex.Message);
+            }
         }
 
         private void CalculateBlocks(Queue<Block> blocksToUpload, int blobLength, ICollection<string> order)