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

extensions/Worker.Extensions.CosmosDB/release_notes.md

@@ -4,8 +4,27 @@
 - My change description (#PR/#issue)
 -->
 
-### Microsoft.Azure.Functions.Worker.Extensions.CosmosDB 4.8.1
+### Microsoft.Azure.Functions.Worker.Extensions.CosmosDB 5.0.0
 
-- 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
+- Expose `CosmosClientOptions` to allow configuration of the CosmosDB client (#2483)
+
+#### Breaking Change
+
+- **Default `ConnectionMode` Change:** The default `ConnectionMode` for `CosmosClientOptions` has been changed from `Gateway` to `Direct`.
+  This change is due to `Direct` being the default value for `ConnectionMode` in the Cosmos SDK; now that we are exposing those options,
+  it is not possible for us to tell whether the user has explicitly set the connection mode to `Direct` or not, so we must default to the
+  SDK's default value
+
+##### How to Maintain Previous Behavior
+
+To continue using `Gateway` mode, configure the `CosmosClientOptions` in your `Program` class as shown below:
+
+```csharp
+.ConfigureFunctionsWorkerDefaults((builder) =>
+{
+    builder.Services.Configure<CosmosClientOptions>((options) =>
+    {
+        options.ConnectionMode = ConnectionMode.Gateway;
+    });
+})
+```

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

@@ -21,6 +21,8 @@ internal class CosmosDBBindingOptions
 
         public CosmosSerializer? Serializer { get; set; }
 
+        public CosmosClientOptions? CosmosClientOptions { get; set; }
+
         internal string BuildCacheKey(string connection, string region) => $"{connection}|{region}";
 
         internal ConcurrentDictionary<string, CosmosClient> ClientCache { get; } = new ConcurrentDictionary<string, CosmosClient>();
@@ -34,29 +36,26 @@ internal virtual CosmosClient GetClient(string preferredLocations = "")
 
             string cacheKey = BuildCacheKey(ConnectionName!, preferredLocations);
 
-            CosmosClientOptions cosmosClientOptions = new ()
-            {
-                ConnectionMode = ConnectionMode.Gateway
-            };
-
-            if (!string.IsNullOrEmpty(preferredLocations))
+            // Do not override if preferred locations is configured via CosmosClientOptions
+            if (!string.IsNullOrEmpty(preferredLocations) && CosmosClientOptions.ApplicationPreferredRegions is null)
             {
-                cosmosClientOptions.ApplicationPreferredRegions = Utilities.ParsePreferredLocations(preferredLocations);
+                CosmosClientOptions.ApplicationPreferredRegions = Utilities.ParsePreferredLocations(preferredLocations);
             }
 
-            if (Serializer is not null)
+            // Do not override if the serializer is configured via CosmosClientOptions
+            if (Serializer is not null && CosmosClientOptions.Serializer is null)
             {
-                cosmosClientOptions.Serializer = Serializer;
+                CosmosClientOptions.Serializer = Serializer;
             }
 
-            return ClientCache.GetOrAdd(cacheKey, (c) => CreateService(cosmosClientOptions));
+            return ClientCache.GetOrAdd(cacheKey, (c) => CreateService());
         }
 
-        private CosmosClient CreateService(CosmosClientOptions cosmosClientOptions)
+        private CosmosClient CreateService()
         {
             return string.IsNullOrEmpty(ConnectionString)
-                    ? new CosmosClient(AccountEndpoint, Credential, cosmosClientOptions) // AAD auth
-                    : new CosmosClient(ConnectionString, cosmosClientOptions); // Connection string based auth
+                    ? new CosmosClient(AccountEndpoint, Credential, CosmosClientOptions) // AAD auth
+                    : 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<CosmosClientOptions> _cosmosClientOptions;
 
-        public CosmosDBBindingOptionsSetup(IConfiguration configuration, AzureComponentFactory componentFactory, IOptionsMonitor<WorkerOptions> workerOptions)
+        public CosmosDBBindingOptionsSetup(IConfiguration configuration, AzureComponentFactory componentFactory, IOptionsMonitor<WorkerOptions> workerOptions, IOptionsMonitor<CosmosClientOptions> cosmosClientOptions)
         {
             _configuration = configuration ?? throw new ArgumentNullException(nameof(configuration));
             _componentFactory = componentFactory ?? throw new ArgumentNullException(nameof(componentFactory));
             _workerOptions = workerOptions ?? throw new ArgumentNullException(nameof(workerOptions));
+            _cosmosClientOptions = cosmosClientOptions ?? throw new ArgumentNullException(nameof(cosmosClientOptions));
         }
 
         public void Configure(CosmosDBBindingOptions options)
@@ -57,6 +60,7 @@ public void Configure(string connectionName, CosmosDBBindingOptions options)
             }
 
             options.Serializer = new WorkerCosmosSerializer(_workerOptions.CurrentValue.Serializer);
+            options.CosmosClientOptions = _cosmosClientOptions.CurrentValue;
         }
     }
 }

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>5.0.0</VersionPrefix>
 
     <!--Temporarily opting out of documentation. Pending documentation-->
     <GenerateDocumentationFile>false</GenerateDocumentationFile>