Implement CosmosDBOptions to allow configuration of the CosmosDB service client via CosmosClientOptions

extensions/Worker.Extensions.CosmosDB/release_notes.md

@@ -4,8 +4,19 @@
 - My change description (#PR/#issue)
 -->
 
-### Microsoft.Azure.Functions.Worker.Extensions.CosmosDB 4.8.1
+### Microsoft.Azure.Functions.Worker.Extensions.CosmosDB 4.9.0
 
-- Updating `Microsoft.Azure.WebJobs.Extensions.CosmosDB` reference to 4.6.1
-- Updating `Microsoft.Extensions.Azure` reference to 1.7.3
-- Updating `Microsoft.Azure.Cosmos` reference to 3.39.1
+- Implement `CosmosDBExtensionOptions` to allow configuration of the CosmosDB service client via `CosmosClientOptions` (#2483)
+
+#### Example Usage
+
+```csharp
+.ConfigureFunctionsWorkerDefaults((builder) =>
+{
+    builder.ConfigureCosmosDBExtensionOptions((options) =>
+    {
+        options.ClientOptions.ConnectionMode = ConnectionMode.Direct;
+        options.ClientOptions.ApplicationName = "MyApp";
+    });
+})
+```

extensions/Worker.Extensions.CosmosDB/src/Config/CosmosDBBindingOptions.cs

@@ -9,6 +9,12 @@
 
 namespace Microsoft.Azure.Functions.Worker
 {
+     /// <summary>
+    /// Internal options for configuring the CosmosDB binding.
+    /// This class is used internally by the Azure Functions runtime to manage the CosmosDB connection and clients.
+    /// It is not intended to be used directly in user code.
+    /// Any public configuration options should be set on the <see cref="CosmosDBExtensionOptions"/> class, which is publicly accessible.
+    /// </summary>
     internal class CosmosDBBindingOptions
     {
         public string? ConnectionName  { get; set; }
@@ -19,7 +25,7 @@ internal class CosmosDBBindingOptions
 
         public TokenCredential? Credential { get; set; }
 
-        public CosmosSerializer? Serializer { get; set; }
+        public CosmosDBExtensionOptions? CosmosExtensionOptions { get; set; }
 
         internal string BuildCacheKey(string connection, string region) => $"{connection}|{region}";
 
@@ -32,24 +38,23 @@ internal virtual CosmosClient GetClient(string preferredLocations = "")
                 throw new ArgumentNullException(nameof(ConnectionName));
             }
 
-            string cacheKey = BuildCacheKey(ConnectionName!, preferredLocations);
-
-            CosmosClientOptions cosmosClientOptions = new ()
-            {
-                ConnectionMode = ConnectionMode.Gateway
-            };
-
-            if (!string.IsNullOrEmpty(preferredLocations))
+            if (CosmosExtensionOptions is null)
             {
-                cosmosClientOptions.ApplicationPreferredRegions = Utilities.ParsePreferredLocations(preferredLocations);
+                CosmosExtensionOptions = new CosmosDBExtensionOptions();
             }
 
-            if (Serializer is not null)
+            string cacheKey = BuildCacheKey(ConnectionName!, preferredLocations);
+
+            // Do not override if preferred locations is configured via CosmosClientOptions
+            if (!string.IsNullOrEmpty(preferredLocations) && CosmosExtensionOptions.ClientOptions.ApplicationPreferredRegions is null)
             {
-                cosmosClientOptions.Serializer = Serializer;
+                // Clone to avoid modifying the original options
+                CosmosClientOptions cosmosClientOptions = CosmosExtensionOptions.ClientOptions.MemberwiseClone<CosmosClientOptions>();
+                cosmosClientOptions.ApplicationPreferredRegions = Utilities.ParsePreferredLocations(preferredLocations);
+                return ClientCache.GetOrAdd(cacheKey, (c) => CreateService(cosmosClientOptions));
             }
 
-            return ClientCache.GetOrAdd(cacheKey, (c) => CreateService(cosmosClientOptions));
+            return ClientCache.GetOrAdd(cacheKey, (c) => CreateService(CosmosExtensionOptions.ClientOptions));
         }
 
         private CosmosClient CreateService(CosmosClientOptions cosmosClientOptions)
@@ -59,4 +64,4 @@ private CosmosClient CreateService(CosmosClientOptions cosmosClientOptions)
                     : new CosmosClient(ConnectionString, cosmosClientOptions); // Connection string based auth
         }
     }
-}
+}

extensions/Worker.Extensions.CosmosDB/src/Config/CosmosDBBindingOptionsSetup.cs

@@ -2,6 +2,7 @@
 // Licensed under the MIT License. See License.txt in the project root for license information.
 
 using System;
+using Microsoft.Azure.Cosmos;
 using Microsoft.Azure.Functions.Worker.Extensions;
 using Microsoft.Azure.Functions.Worker.Extensions.CosmosDB;
 using Microsoft.Extensions.Azure;
@@ -15,12 +16,14 @@ internal class CosmosDBBindingOptionsSetup : IConfigureNamedOptions<CosmosDBBind
         private readonly IConfiguration _configuration;
         private readonly AzureComponentFactory _componentFactory;
         private readonly IOptionsMonitor<WorkerOptions> _workerOptions;
+        private readonly IOptionsMonitor<CosmosDBExtensionOptions> _cosmosExtensionOptions;
 
-        public CosmosDBBindingOptionsSetup(IConfiguration configuration, AzureComponentFactory componentFactory, IOptionsMonitor<WorkerOptions> workerOptions)
+        public CosmosDBBindingOptionsSetup(IConfiguration configuration, AzureComponentFactory componentFactory, IOptionsMonitor<WorkerOptions> workerOptions, IOptionsMonitor<CosmosDBExtensionOptions> cosmosExtensionOptions)
         {
             _configuration = configuration ?? throw new ArgumentNullException(nameof(configuration));
             _componentFactory = componentFactory ?? throw new ArgumentNullException(nameof(componentFactory));
             _workerOptions = workerOptions ?? throw new ArgumentNullException(nameof(workerOptions));
+            _cosmosExtensionOptions = cosmosExtensionOptions ?? throw new ArgumentNullException(nameof(cosmosExtensionOptions));
         }
 
         public void Configure(CosmosDBBindingOptions options)
@@ -56,7 +59,7 @@ public void Configure(string connectionName, CosmosDBBindingOptions options)
                 options.Credential = _componentFactory.CreateTokenCredential(connectionSection);
             }
 
-            options.Serializer = new WorkerCosmosSerializer(_workerOptions.CurrentValue.Serializer);
+            options.CosmosExtensionOptions = _cosmosExtensionOptions.CurrentValue;
         }
     }
-}
+}

extensions/Worker.Extensions.CosmosDB/src/Config/CosmosDBExtensionOptions.cs

@@ -0,0 +1,15 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the MIT License. See License.txt in the project root for license information.
+
+using Microsoft.Azure.Cosmos;
+
+namespace Microsoft.Azure.Functions.Worker
+{
+    public class CosmosDBExtensionOptions
+    {
+        /// <summary>
+        /// Gets or sets the CosmosClientOptions.
+        /// </summary>
+        public CosmosClientOptions ClientOptions { get; set; } = new() { ConnectionMode = ConnectionMode.Gateway };
+    }
+}

extensions/Worker.Extensions.CosmosDB/src/Extensions/CloningExtensions.cs

@@ -0,0 +1,34 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the MIT License. See License.txt in the project root for license information.
+
+using System;
+using System.Reflection;
+using Microsoft.Azure.Cosmos;
+
+namespace Microsoft.Azure.Functions.Worker
+{
+    internal static class CloningExtensions
+    {
+        public static T MemberwiseClone<T>(this T original)
+        {
+            if (original is null)
+            {
+                throw new ArgumentNullException(nameof(original));
+            }
+
+            // Get the type of the object
+            Type type = original.GetType();
+
+            // Get the internal Clone method
+            MethodInfo cloneMethod = type.GetMethod("MemberwiseClone", BindingFlags.Instance | BindingFlags.NonPublic);
+
+            if (cloneMethod is null)
+            {
+                throw new InvalidOperationException("The MemberwiseClone method could not be found.");
+            }
+
+            // Invoke the Clone method
+            return (T)cloneMethod.Invoke(original, null);
+        }
+    }
+}

extensions/Worker.Extensions.CosmosDB/src/Extensions/FunctionsWorkerApplicationBuilderExtensions.cs

@@ -1,6 +1,8 @@
 // Copyright (c) .NET Foundation. All rights reserved.
 // Licensed under the MIT License. See License.txt in the project root for license information.
 
+using System;
+using Microsoft.Azure.Cosmos;
 using Microsoft.Extensions.Azure;
 using Microsoft.Extensions.DependencyInjection;
 using Microsoft.Extensions.DependencyInjection.Extensions;
@@ -27,9 +29,30 @@ public static IFunctionsWorkerApplicationBuilder ConfigureCosmosDBExtension(this
 
             builder.Services.AddAzureClientsCore(); // Adds AzureComponentFactory
             builder.Services.AddOptions<CosmosDBBindingOptions>();
+            builder.Services.AddOptions<CosmosDBExtensionOptions>()
+                            .Configure<IOptions<WorkerOptions>>((cosmos, worker) =>
+                            {
+                                if (cosmos.ClientOptions.Serializer is null)
+                                {
+                                    cosmos.ClientOptions.Serializer = new WorkerCosmosSerializer(worker.Value.Serializer);
+                                }
+                            });
+
             builder.Services.TryAddEnumerable(ServiceDescriptor.Singleton<IConfigureOptions<CosmosDBBindingOptions>, CosmosDBBindingOptionsSetup>());
 
             return builder;
         }
+
+        /// <summary>
+        /// Configures the CosmosDBExtensionOptions for the Functions Worker Cosmos extension.
+        /// </summary>
+        /// <param name="builder">The IFunctionsWorkerApplicationBuilder to add the configuration to.</param>
+        /// <param name="options">An Action to configure the CosmosDBExtensionOptions.</param>
+        /// <returns>The same instance of the <see cref="IFunctionsWorkerApplicationBuilder"/> for chaining.</returns>
+        public static IFunctionsWorkerApplicationBuilder ConfigureCosmosDBExtensionOptions(this IFunctionsWorkerApplicationBuilder builder, Action<CosmosDBExtensionOptions> options)
+        {
+            builder.Services.Configure(options);
+            return builder;
+        }
     }
 }

extensions/Worker.Extensions.CosmosDB/src/Worker.Extensions.CosmosDB.csproj

@@ -6,7 +6,7 @@
     <Description>Azure Cosmos DB extensions for .NET isolated functions</Description>
 
     <!--Version information-->
-    <VersionPrefix>4.8.1</VersionPrefix>
+    <VersionPrefix>4.9.0</VersionPrefix>
 
     <!--Temporarily opting out of documentation. Pending documentation-->
     <GenerateDocumentationFile>false</GenerateDocumentationFile>