Address CR.

Framework/Common/ServiceBusUtils.cs

@@ -137,7 +137,7 @@ static async Task<BrokeredMessage> GenerateBrokeredMessageWithStorageKeyProperty
             // save the compressed stream using external storage when it is larger
             // than the supported message size limit.
             // the stream is stored using the generated key, which is saved in the message property.
-            string storageKey = orchestrationServiceBlobStore.BuildMessageStorageKey(instance, messageFireTime);
+            string storageKey = orchestrationServiceBlobStore.BuildMessageBlobKey(instance, messageFireTime);
 
             TraceHelper.TraceInstance(
                 TraceEventType.Information,

Framework/Serializing/RuntimeStateStreamConverter.cs

@@ -28,7 +28,7 @@ namespace DurableTask.Serializing
     /// <summary>
     /// A converter that does conversion between the OrchestrationRuntimeState instance and a stream after serialization.
     /// The stream is a serialized OrchestrationSessionState that will set as session state.
-    /// De-serialization is done with fallbacks in the order: OrchestrationSessionState -> OrchestrationRuntimeState -> IList<HistoryEvent>.
+    /// De-serialization is done with fallbacks in the order: OrchestrationSessionState -> OrchestrationRuntimeState -> IList of HistoryEvent.
     /// </summary>
     class RuntimeStateStreamConverter
     {
@@ -96,7 +96,7 @@ async static Task<Stream> CreateStreamForExternalStorageAsync(
             }
 
             // create a new orchestration session state with the external storage key
-            string key = orchestrationServiceBlobStore.BuildSessionStorageKey(sessionId);
+            string key = orchestrationServiceBlobStore.BuildSessionBlobKey(sessionId);
             OrchestrationSessionState orchestrationSessionState = new OrchestrationSessionState(key);
 
             string serializedStateExternal = dataConverter.Serialize(orchestrationSessionState);
@@ -197,11 +197,11 @@ static OrchestrationRuntimeState GetOrCreateInstanceState(Stream stateStream, st
         /// Deserialize the session state to construct an OrchestrationRuntimeState instance.
         ///
         /// The session state string could be one of these:
-        ///     1. a serialized IList<HistoryEvent> (master branch implementation), or
+        ///     1. a serialized IList of HistoryEvent (master branch implementation), or
         ///     2. a serialized OrchestrationRuntimeState instance with the history event list (vnext branch implementation), or
         ///     3. a serialized OrchestrationSessionState instance with the history event list or a storage key (latest implementation).
         ///
-        /// So when doing the deserialization, it is done with fallbacks in the order: OrchestrationSessionState -> OrchestrationRuntimeState -> IList<HistoryEvent>, to cover all cases.
+        /// So when doing the deserialization, it is done with fallbacks in the order: OrchestrationSessionState -> OrchestrationRuntimeState -> IList of HistoryEvent, to cover all cases.
         ///
         /// </summary>
         /// <param name="serializedState">The serialized session state</param>
@@ -225,7 +225,7 @@ static OrchestrationRuntimeState DeserializeToRuntimeStateWithFallback(string se
                 TraceHelper.TraceSession(
                     TraceEventType.Warning,
                     sessionId,
-                    $"Failed to deserialize session state to OrchestrationSessionState object: {serializedState}");
+                    $"Failed to deserialize session state to OrchestrationSessionState object: {serializedState}. More info: {exception.StackTrace}");
                 try
                 {
                     OrchestrationRuntimeState restoredState =
@@ -238,7 +238,7 @@ static OrchestrationRuntimeState DeserializeToRuntimeStateWithFallback(string se
                     TraceHelper.TraceSession(
                         TraceEventType.Warning,
                         sessionId,
-                        $"Failed to deserialize session state to OrchestrationRuntimeState object: {serializedState}");
+                        $"Failed to deserialize session state to OrchestrationRuntimeState object: {serializedState}. More info: {e.StackTrace}");
 
                     IList<HistoryEvent> events = dataConverter.Deserialize<IList<HistoryEvent>>(serializedState);
                     runtimeState = new OrchestrationRuntimeState(events);

Framework/ServiceBusOrchestrationService.cs

@@ -1415,7 +1415,7 @@ async Task<bool> TrySetSessionState(
 
                 isSessionSizeThresholdExceeded = true;
 
-                string reason = $"Session state size of {runtimeState.CompressedSize} exceeded the termination threshold of {Settings.SessionSettings.SessionMaxSizeInBytes} bytes";
+                string reason = $"Session state size of {runtimeState.CompressedSize} exceeded the termination threshold of {Settings.SessionSettings.SessionMaxSizeInBytes} bytes. More info: {exception.StackTrace}";
                 TraceHelper.TraceSession(TraceEventType.Critical, workItem.InstanceId, reason);
 
                 BrokeredMessage forcedTerminateMessage = await CreateForcedTerminateMessageAsync(runtimeState.OrchestrationInstance.InstanceId, reason);

Framework/Tracking/AzureStorageBlobStore.cs

@@ -22,37 +22,29 @@ namespace DurableTask.Tracking
     /// </summary>
     public class AzureStorageBlobStore : IOrchestrationServiceBlobStore
     {
+        /// <summary>
+        /// The client to access and manage the blob store
+        /// </summary>
         readonly BlobStorageClient blobClient;
 
         /// <summary>
         /// Creates a new AzureStorageBlobStore using the supplied hub name and connection string
         /// </summary>
-        /// <param name="hubName">The hubname for this store</param>
+        /// <param name="hubName">The hub name for this store</param>
         /// <param name="connectionString">Azure storage connection string</param>
         public AzureStorageBlobStore(string hubName, string connectionString)
         {
             this.blobClient = new BlobStorageClient(hubName, connectionString);
         }
 
         /// <summary>
-        /// Create a storage key based on the creation date.
-        /// This key will be used to save and load the stream in external storage when it is too large.
-        /// </summary>
-        /// <param name="creationDate">The creation date of the blob. Could be DateTime.MinValue if want to use current time.</param>
-        /// <returns>A storage key.</returns>
-        public string BuildStorageKey(DateTime creationDate)
-        {
-            return BlobStorageClientHelper.BuildStorageKey(creationDate);
-        }
-
-        /// <summary>
-        /// Create a storage key based on the orchestrationInstance.
+        /// Create a blob storage access key based on the orchestrationInstance.
         /// This key will be used to save and load the stream message in external storage when it is too large.
         /// </summary>
         /// <param name="orchestrationInstance">The orchestration instance.</param>
         /// <param name="messageFireTime">The message fire time.</param>
         /// <returns>The created storage key.</returns>
-        public string BuildMessageStorageKey(OrchestrationInstance orchestrationInstance, DateTime messageFireTime)
+        public string BuildMessageBlobKey(OrchestrationInstance orchestrationInstance, DateTime messageFireTime)
         {
             return BlobStorageClientHelper.BuildMessageStorageKey(
                 orchestrationInstance != null ? orchestrationInstance.InstanceId : "null",
@@ -61,43 +53,43 @@ public string BuildMessageStorageKey(OrchestrationInstance orchestrationInstance
         }
 
         /// <summary>
-        /// Create a storage key based on message session.
+        /// Create a blob storage access key based on message session.
         /// This key will be used to save and load the stream in external storage when it is too large.
         /// </summary>
         /// <param name="sessionId">The message session Id.</param>
         /// <returns>A storage key.</returns>
-        public string BuildSessionStorageKey(string sessionId)
+        public string BuildSessionBlobKey(string sessionId)
         {
             return BlobStorageClientHelper.BuildSessionStorageKey(sessionId);
         }
 
         /// <summary>
         /// Save the stream of the message or seesion using key.
         /// </summary>
-        /// <param name="key">The storage key.</param>
+        /// <param name="blobKey">The blob storage key.</param>
         /// <param name="stream">The stream of the message or session.</param>
         /// <returns></returns>
-        public async Task SaveStreamAsync(string key, Stream stream)
+        public async Task SaveStreamAsync(string blobKey, Stream stream)
         {
-            await this.blobClient.UploadStreamBlob(key, stream);
+            await this.blobClient.UploadStreamBlobAsync(blobKey, stream);
         }
 
         /// <summary>
         /// Load the stream of message or seesion from storage using key.
         /// </summary>
-        /// <param name="key">Teh storage key.</param>
+        /// <param name="blobKey">The blob storage key.</param>
         /// <returns>The saved stream message or session.</returns>
-        public async Task<Stream> LoadStreamAsync(string key)
+        public async Task<Stream> LoadStreamAsync(string blobKey)
         {
-            return await this.blobClient.DownloadStreamAsync(key);
+            return await this.blobClient.DownloadStreamAsync(blobKey);
         }
 
         /// <summary>
         /// Deletes the Azure blob storage
         /// </summary>
         public async Task DeleteStoreAsync()
         {
-            await this.blobClient.DeleteAllContainersAsync();
+            await this.blobClient.DeleteBlobStoreContainersAsync();
         }
 
         /// <summary>

Framework/Tracking/BlobStorageClient.cs

@@ -55,9 +55,9 @@ public BlobStorageClient(string hubName, string connectionString)
                 throw new ArgumentException("Invalid hub name", nameof(hubName));
             }
 
-            blobClient = CloudStorageAccount.Parse(connectionString).CreateCloudBlobClient();
-            blobClient.DefaultRequestOptions.RetryPolicy = new ExponentialRetry(DeltaBackOff, MaxRetries);
-            blobClient.DefaultRequestOptions.MaximumExecutionTime = MaximumExecutionTime;
+            this.blobClient = CloudStorageAccount.Parse(connectionString).CreateCloudBlobClient();
+            this.blobClient.DefaultRequestOptions.RetryPolicy = new ExponentialRetry(DeltaBackOff, MaxRetries);
+            this.blobClient.DefaultRequestOptions.MaximumExecutionTime = MaximumExecutionTime;
 
             // save the lower case since it will be used as the prefix of the container name,
             // which only allows lower case letters
@@ -70,12 +70,12 @@ public BlobStorageClient(string hubName, string connectionString)
         /// <param name="key">The key to uniquely locate and access the blob</param>
         /// <param name="stream">The stream to be uploaded</param>
         /// <returns></returns>
-        public async Task UploadStreamBlob(string key, Stream stream)
+        public async Task UploadStreamBlobAsync(string key, Stream stream)
         {
             string containerNameSuffix;
             string blobName;
             BlobStorageClientHelper.ParseKey(key, out containerNameSuffix, out blobName);
-            var cloudBlob = await GetCloudBlockBlobReferenceAsync(containerNameSuffix, blobName);
+            var cloudBlob = await this.GetCloudBlockBlobReferenceAsync(containerNameSuffix, blobName);
             await cloudBlob.UploadFromStreamAsync(stream);
         }
 
@@ -100,7 +100,7 @@ public async Task<Stream> DownloadStreamAsync(string key)
         async Task<ICloudBlob> GetCloudBlockBlobReferenceAsync(string containerNameSuffix, string blobName)
         {
             string containerName = BlobStorageClientHelper.BuildContainerName(hubName, containerNameSuffix);
-            var cloudBlobContainer = blobClient.GetContainerReference(containerName);
+            var cloudBlobContainer = this.blobClient.GetContainerReference(containerName);
             await cloudBlobContainer.CreateIfNotExistsAsync();
             return cloudBlobContainer.GetBlockBlobReference(blobName);
         }
@@ -111,7 +111,7 @@ async Task<ICloudBlob> GetCloudBlockBlobReferenceAsync(string containerNameSuffi
         /// <returns>A list of Azure blob containers</returns>
         public IEnumerable<CloudBlobContainer> ListContainers()
         {
-            return blobClient.ListContainers(hubName);
+            return this.blobClient.ListContainers(this.hubName);
         }
 
         /// <summary>
@@ -127,12 +127,12 @@ public async Task DeleteExpiredContainersAsync(DateTime thresholdDateTimeUtc)
         }
 
         /// <summary>
-        /// Delete all containers with the hub name as prefix.
+        /// Delete blob containers with the hub name as prefix.
         /// </summary>
         /// <returns></returns>
-        public async Task DeleteAllContainersAsync()
+        public async Task DeleteBlobStoreContainersAsync()
         {
-            IEnumerable<CloudBlobContainer> containers = ListContainers();
+            IEnumerable<CloudBlobContainer> containers = this.ListContainers();
             var tasks = containers.ToList().Select(container => container.DeleteIfExistsAsync());
             await Task.WhenAll(tasks);
         }

Framework/Tracking/BlobStorageClientHelper.cs

@@ -26,22 +26,15 @@ public class BlobStorageClientHelper
         static readonly string DateFormat = "yyyyMMdd";
         static readonly char ContainerNameDelimiter = '-';
 
-        // the blob storage accesss key is in the format of {DateTime}|{blobName}
+        /// <summary>
+        /// the blob storage accesss key is in the format of {DateTime}|{blobName}
+        /// </summary>
         public static readonly char KeyDelimiter = '|';
 
-        // the delimiter shown in the blob name as the file path
-        public static readonly char BlobNameDelimiter = '/';
-
         /// <summary>
-        /// Build a storage key using the creation time specified.
+        /// the delimiter shown in the blob name as the file path
         /// </summary>
-        /// <param name="blobCreationTime">The specified creation time</param>
-        /// <returns>The constructed storage key.</returns>
-        public static string BuildStorageKey(DateTime blobCreationTime)
-        {
-            string id = Guid.NewGuid().ToString("N");
-            return $"{BuildContainerNameSuffix("blob", blobCreationTime)}{KeyDelimiter}{id}";
-        }
+        public static readonly char BlobNameDelimiter = '/';
 
         /// <summary>
         /// Build a storage key for the message.

Framework/Tracking/IOrchestrationServiceBlobStore.cs

@@ -19,48 +19,42 @@ namespace DurableTask.Tracking
 
     /// <summary>
     /// Interface to allow save and load large blobs, such as message and session, as a stream using a storage store.
+    /// The blob is saved in the store using an access key (e.g., a path to the blob),
+    /// which can be used to uniquely load the blob back.
     /// </summary>
     public interface IOrchestrationServiceBlobStore
     {
         /// <summary>
-        /// Create a storage key based on the creation date.
-        /// This key will be used to save and load the stream in external storage when it is too large.
-        /// </summary>
-        /// <param name="creationDate">The creation date of the blob. Could be DateTime.MinValue if want to use current time.</param>
-        /// <returns>A storage key.</returns>
-        string BuildStorageKey(DateTime creationDate);
-
-        /// <summary>
-        /// Create a storage key based on the orchestrationInstance.
+        /// Create a blob storage access key based on the orchestrationInstance.
         /// This key will be used to save and load the stream message in external storage when it is too large.
         /// </summary>
         /// <param name="orchestrationInstance">The orchestration instance.</param>
         /// <param name="messageFireTime">The message fire time. Could be DateTime.MinValue.</param>
         /// <returns>A message storage key.</returns>
-        string BuildMessageStorageKey(OrchestrationInstance orchestrationInstance, DateTime messageFireTime);
+        string BuildMessageBlobKey(OrchestrationInstance orchestrationInstance, DateTime messageFireTime);
 
         /// <summary>
-        /// Create a storage key based on message session.
+        /// Create a blob storage access key based on message session.
         /// This key will be used to save and load the stream in external storage when it is too large.
         /// </summary>
         /// <param name="sessionId">The message session Id.</param>
         /// <returns>A storage key.</returns>
-        string BuildSessionStorageKey(string sessionId);
+        string BuildSessionBlobKey(string sessionId);
 
         /// <summary>
         /// Save the stream of the message or seesion using key.
         /// </summary>
-        /// <param name="key">The storage key.</param>
+        /// <param name="blobKey">The blob storage key.</param>
         /// <param name="stream">The stream of the message or session.</param>
         /// <returns></returns>
-        Task SaveStreamAsync(string key, Stream stream);
+        Task SaveStreamAsync(string blobKey, Stream stream);
 
         /// <summary>
         /// Load the stream of message or seesion from storage using key.
         /// </summary>
-        /// <param name="key">Teh storage key.</param>
+        /// <param name="blobKey">The blob storage key.</param>
         /// <returns>The saved stream message or session.</returns>
-        Task<Stream> LoadStreamAsync(string key);
+        Task<Stream> LoadStreamAsync(string blobKey);
 
         /// <summary>
         /// Deletes the blob store

FrameworkUnitTests/BlobStorageClientHelperTest.cs

@@ -39,19 +39,6 @@ public void IsContainerExpiredTest()
             Assert.IsFalse(BlobStorageClientHelper.IsContainerExpired("invalidContainerName", DateTime.UtcNow));
         }
 
-        [TestMethod]
-        public void BuildStorageKeyTest()
-        {
-            DateTime messageFireTime = new DateTime(2015, 05, 17);
-            string key = BlobStorageClientHelper.BuildStorageKey(messageFireTime);
-            Regex regex = new Regex(@"blob-20150517|\w{32}$");
-            Assert.IsTrue(regex.Match(key).Success);
-
-            key = BlobStorageClientHelper.BuildStorageKey(DateTime.MinValue);
-            regex = new Regex(@"blob-\d{8}|\w{32}$");
-            Assert.IsTrue(regex.Match(key).Success);
-        }
-
         [TestMethod]
         public void BuildMessageStorageKeyTest()
         {