Adding Storage Backend Selection in host.json (#1702)

These changes allow customers to configure which storage backend they want their app to use (e.g. Azure Storage, MicrosoftSQL, or Netherite) with a new type attribute under durableTask/storageProvider in host.json. The extension will register all storage backend services and then choose which one to use in the DurableTaskExtension constructor. Adding the ability to register all backends and then choose a storage backend allows us to deploy all storage backend packages through extension bundles.

The main changes in this PR are allowing the extension to register a collection of services through dependency injection, adding a Name property in IDurabilityProviderFactory, and choosing the DurabilityProvider by comparing a customers configured type with the Name property in the available IDurabilityProviderFactory implementations.

Resolves #1666

Author: bachuv

release_notes.md

@@ -1 +1,5 @@
-Improved concurrency defaults for the App Service Consumption plan (https://github.com/Azure/azure-functions-durable-extension/pull/1706)
+## New Features
+- Added support to select a storage backend provider when multiple are installed (#1702): Select which storage backend to use by setting the `type` field under `durableTask/storageProvider` in host.json. If this field isn't set, then the storage backend will default to using Azure Storage.
+
+- Improved concurrency defaults for the App Service Consumption plan (https://github.com/Azure/azure-functions-durable-extension/pull/1706)
+

src/WebJobs.Extensions.DurableTask/AzureStorageDurabilityProviderFactory.cs

@@ -11,6 +11,8 @@ namespace Microsoft.Azure.WebJobs.Extensions.DurableTask
 {
     internal class AzureStorageDurabilityProviderFactory : IDurabilityProviderFactory
     {
+        internal const string ProviderName = "AzureStorage";
+
         private readonly DurableTaskOptions options;
         private readonly AzureStorageOptions azureStorageOptions;
         private readonly IConnectionStringResolver connectionStringResolver;
@@ -59,6 +61,8 @@ public AzureStorageDurabilityProviderFactory(
             this.defaultConnectionName = this.azureStorageOptions.ConnectionStringName ?? ConnectionStringNames.Storage;
         }
 
+        public string Name => ProviderName;
+
         internal string GetDefaultStorageConnectionString()
         {
             return this.connectionStringResolver.Resolve(this.defaultConnectionName);

src/WebJobs.Extensions.DurableTask/DurableTaskExtension.cs

@@ -46,6 +46,8 @@ public class DurableTaskExtension :
         INameVersionObjectManager<TaskOrchestration>,
         INameVersionObjectManager<TaskActivity>
     {
+        private const string DefaultProvider = AzureStorageDurabilityProviderFactory.ProviderName;
+
         internal static readonly string LoggerCategoryName = LogCategories.CreateTriggerCategory("DurableTask");
 
         // Creating client objects is expensive, so we cache them when the attributes match.
@@ -81,7 +83,6 @@ public class DurableTaskExtension :
         private bool isTaskHubWorkerStarted;
         private HttpClient durableHttpClient;
         private EventSourceListener eventSourceListener;
-
 #if FUNCTIONS_V1
         private IConnectionStringResolver connectionStringResolver;
 
@@ -103,7 +104,7 @@ public DurableTaskExtension()
         /// <param name="options">The configuration options for this extension.</param>
         /// <param name="loggerFactory">The logger factory used for extension-specific logging and orchestration tracking.</param>
         /// <param name="nameResolver">The name resolver to use for looking up application settings.</param>
-        /// <param name="orchestrationServiceFactory">The factory used to create orchestration service based on the configured storage provider.</param>
+        /// <param name="orchestrationServiceFactories">The factories used to create orchestration service based on the configured storage provider.</param>
         /// <param name="durableHttpMessageHandlerFactory">The HTTP message handler that handles HTTP requests and HTTP responses.</param>
         /// <param name="hostLifetimeService">The host shutdown notification service for detecting and reacting to host shutdowns.</param>
         /// <param name="lifeCycleNotificationHelper">The lifecycle notification helper used for custom orchestration tracking.</param>
@@ -116,7 +117,7 @@ public DurableTaskExtension(
             IOptions<DurableTaskOptions> options,
             ILoggerFactory loggerFactory,
             INameResolver nameResolver,
-            IDurabilityProviderFactory orchestrationServiceFactory,
+            IEnumerable<IDurabilityProviderFactory> orchestrationServiceFactories,
             IApplicationLifetimeWrapper hostLifetimeService,
             IDurableHttpMessageHandlerFactory durableHttpMessageHandlerFactory = null,
             ILifeCycleNotificationHelper lifeCycleNotificationHelper = null,
@@ -145,7 +146,7 @@ public DurableTaskExtension(
 
             this.TraceHelper = new EndToEndTraceHelper(logger, this.Options.Tracing.TraceReplayEvents);
             this.LifeCycleNotificationHelper = lifeCycleNotificationHelper ?? this.CreateLifeCycleNotificationHelper();
-            this.durabilityProviderFactory = orchestrationServiceFactory;
+            this.durabilityProviderFactory = this.GetDurabilityProviderFactory(this.Options, logger, orchestrationServiceFactories);
             this.defaultDurabilityProvider = this.durabilityProviderFactory.GetDurabilityProvider();
             this.isOptionsConfigured = true;
 
@@ -178,15 +179,15 @@ internal DurableTaskExtension(
             IOptions<DurableTaskOptions> options,
             ILoggerFactory loggerFactory,
             INameResolver nameResolver,
-            IDurabilityProviderFactory orchestrationServiceFactory,
+            IEnumerable<IDurabilityProviderFactory> orchestrationServiceFactories,
             IConnectionStringResolver connectionStringResolver,
             IApplicationLifetimeWrapper shutdownNotification,
             IDurableHttpMessageHandlerFactory durableHttpMessageHandlerFactory,
 #pragma warning disable CS0612 // Type or member is obsolete
             IPlatformInformationService platformInformationService)
 #pragma warning restore CS0612 // Type or member is obsolete
 
-            : this(options, loggerFactory, nameResolver, orchestrationServiceFactory, shutdownNotification, durableHttpMessageHandlerFactory)
+            : this(options, loggerFactory, nameResolver, orchestrationServiceFactories, shutdownNotification, durableHttpMessageHandlerFactory)
         {
             this.connectionStringResolver = connectionStringResolver;
             this.platformInformationService = platformInformationService;
@@ -249,6 +250,37 @@ private MessagePayloadDataConverter CreateErrorDataConverter(IErrorSerializerSet
             return new MessagePayloadDataConverter(errorSerializerSettingsFactory.CreateJsonSerializerSettings(), isDefault);
         }
 
+        private IDurabilityProviderFactory GetDurabilityProviderFactory(DurableTaskOptions options, ILogger logger, IEnumerable<IDurabilityProviderFactory> orchestrationServiceFactories)
+        {
+            bool storageTypeIsConfigured = options.StorageProvider.TryGetValue("type", out object storageType);
+
+            if (!storageTypeIsConfigured)
+            {
+                try
+                {
+                    IDurabilityProviderFactory defaultFactory = orchestrationServiceFactories.First(f => f.Name.Equals(DefaultProvider));
+                    logger.LogInformation($"Using the default storage provider: {DefaultProvider}.");
+                    return defaultFactory;
+                }
+                catch (InvalidOperationException e)
+                {
+                    throw new InvalidOperationException($"Couldn't find the default storage provider: {DefaultProvider}.", e);
+                }
+            }
+
+            try
+            {
+                IDurabilityProviderFactory selectedFactory = orchestrationServiceFactories.First(f => string.Equals(f.Name, storageType.ToString(), StringComparison.OrdinalIgnoreCase));
+                logger.LogInformation($"Using the {storageType} storage provider.");
+                return selectedFactory;
+            }
+            catch (InvalidOperationException e)
+            {
+                IList<string> factoryNames = orchestrationServiceFactories.Select(f => f.Name).ToList();
+                throw new InvalidOperationException($"Storage provider type ({storageType}) was not found. Available storage providers: {string.Join(", ", factoryNames)}.", e);
+            }
+        }
+
         internal string GetBackendInfo()
         {
             return this.defaultDurabilityProvider.GetBackendInfo();

src/WebJobs.Extensions.DurableTask/DurableTaskJobHostConfigurationExtensions.cs

@@ -80,7 +80,7 @@ public static IWebJobsBuilder AddDurableTask(this IWebJobsBuilder builder)
                 .Services.AddSingleton<IConnectionStringResolver, WebJobsConnectionStringProvider>();
 
             serviceCollection.TryAddSingleton<IDurableHttpMessageHandlerFactory, DurableHttpMessageHandlerFactory>();
-            serviceCollection.TryAddSingleton<IDurabilityProviderFactory, AzureStorageDurabilityProviderFactory>();
+            serviceCollection.AddSingleton<IDurabilityProviderFactory, AzureStorageDurabilityProviderFactory>();
             serviceCollection.TryAddSingleton<IMessageSerializerSettingsFactory, MessageSerializerSettingsFactory>();
             serviceCollection.TryAddSingleton<IErrorSerializerSettingsFactory, ErrorSerializerSettingsFactory>();
             serviceCollection.TryAddSingleton<IApplicationLifetimeWrapper, HostLifecycleService>();

src/WebJobs.Extensions.DurableTask/IDurabilityProviderFactory.cs

@@ -8,6 +8,11 @@ namespace Microsoft.Azure.WebJobs.Extensions.DurableTask
     /// </summary>
     public interface IDurabilityProviderFactory
     {
+        /// <summary>
+        /// Specifies the Durability Provider Factory name.
+        /// </summary>
+        string Name { get; }
+
         /// <summary>
         /// Creates or retrieves a durability provider to be used throughout the extension.
         /// </summary>

src/WebJobs.Extensions.DurableTask/Microsoft.Azure.WebJobs.Extensions.DurableTask-net461.xml

@@ -337,7 +337,7 @@ private static DurableTaskExtension GetDurableTaskConfig()
                 wrappedOptions,
                 new LoggerFactory(),
                 nameResolver,
-                serviceFactory,
+                new[] { serviceFactory },
                 new TestHostShutdownNotificationService(),
                 new DurableHttpMessageHandlerFactory(),
                 platformInformationService: platformInformationService);