Allowing gRPC channel options to be passed in during service invocation

src/Dapr.Client/DaprClient.cs

@@ -144,6 +144,50 @@ public static CallInvoker CreateInvocationInvoker(string appId, string? daprEndp
         return channel.Intercept(new InvocationInterceptor(appId, daprApiToken ?? DaprDefaults.GetDefaultDaprApiToken(null)));
     }
 
+    /// <summary>
+    /// <para>
+    /// Creates an <see cref="CallInvoker"/> that can be used to perform locally defined gRPC calls
+    /// using the Dapr sidecar as a proxy.
+    /// </para>
+    /// <para>
+    /// The created <see cref="CallInvoker"/> is used to intercept a <see cref="GrpcChannel"/> with an
+    /// <see cref="InvocationInterceptor"/>. The interceptor inserts the <paramref name="appId"/> and, if present,
+    /// the <paramref name="daprApiToken"/> into the request's metadata.
+    /// </para>
+    /// </summary>
+    /// <param name="appId">
+    /// The appId that is targetted by Dapr for gRPC invocations.
+    /// </param>
+    /// <param name="grpcChannelOptions">
+    /// The options to use when creating the <see cref="GrpcChannel"/>.
+    /// </param>
+    /// <param name="daprEndpoint">
+    /// Optional gRPC endpoint for calling Dapr, defaults to <see cref="DaprDefaults.GetDefaultGrpcEndpoint"/>.
+    /// </param>
+    /// <param name="daprApiToken">
+    /// Optional token to be attached to all requests, defaults to <see cref="DaprDefaults.GetDefaultDaprApiToken"/>.
+    /// </param>
+    /// <returns>An <see cref="CallInvoker"/> to be used for proxied gRPC calls through Dapr.</returns>
+    /// <remarks>
+    /// <para>
+    /// As the <paramref name="daprEndpoint"/> will remain constant, a single instance of the
+    /// <see cref="CallInvoker"/> can be used throughout the lifetime of the application.
+    /// </para>
+    /// </remarks>
+    public static CallInvoker CreateInvocationInvoker(
+        string appId,
+        GrpcChannelOptions grpcChannelOptions,
+        string? daprEndpoint = null,
+        string? daprApiToken = null)
+    {
+        ArgumentNullException.ThrowIfNull(grpcChannelOptions);
+
+        var channel = GrpcChannel.ForAddress(
+            daprEndpoint ?? DaprDefaults.GetDefaultGrpcEndpoint(),
+            grpcChannelOptions);
+        return channel.Intercept(new InvocationInterceptor(appId, daprApiToken ?? DaprDefaults.GetDefaultDaprApiToken(null)));
+    }
+
     internal static KeyValuePair<string, string>? GetDaprApiTokenHeader(string apiToken)
     {
         return string.IsNullOrWhiteSpace(apiToken)

test/Dapr.Client.Test/DaprClientTest.cs

@@ -12,7 +12,12 @@
 // ------------------------------------------------------------------------
 
 using System;
+using System.Linq;
+using System.Net.Http;
 using System.Threading.Tasks;
+using Dapr;
+using Grpc.Core;
+using Grpc.Net.Client;
 using Xunit;
 
 namespace Dapr.Client;
@@ -68,6 +73,36 @@ public void CreateInvokeHttpClient_InvalidDaprEndpoint_InvalidScheme()
         Assert.Contains("The URI scheme of the Dapr endpoint must be http or https.", ex.Message);
     }
 
+    [Fact]
+    public async Task CreateInvocationInvoker_UsesGrpcChannelOptions()
+    {
+        await using var testClient = TestClient.CreateForMessageHandler();
+        using var httpClient = new HttpClient(testClient.InnerClient);
+        var invoker = DaprClient.CreateInvocationInvoker(
+            appId: "bank",
+            grpcChannelOptions: new GrpcChannelOptions { HttpClient = httpClient },
+            daprEndpoint: "http://localhost");
+        var method = new Method<string, string>(
+            MethodType.Unary,
+            "test.Service",
+            "TestMethod",
+            Marshallers.StringMarshaller,
+            Marshallers.StringMarshaller);
+
+        var request = await testClient.CaptureGrpcRequestAsync(
+            _ => invoker.AsyncUnaryCall(method, null, new CallOptions(), "request").ResponseAsync);
+
+        Assert.Equal("bank", request.Request.Headers.GetValues("dapr-app-id").Single());
+        request.Dismiss();
+    }
+
+    [Fact]
+    public void CreateInvocationInvoker_WithNullGrpcChannelOptions_Throws()
+    {
+        Assert.Throws<ArgumentNullException>(
+            () => DaprClient.CreateInvocationInvoker(grpcChannelOptions: null!, appId: "bank"));
+    }
+
     [Fact]
     public void GetDaprApiTokenHeader_ApiTokenSet_SetsApiTokenHeader()
     {