set primary user agent by C# channel

src/csharp/Grpc.Core.Tests/ClientServerTest.cs

@@ -33,6 +33,7 @@
 
 using System;
 using System.Diagnostics;
+using System.Linq;
 using System.Threading;
 using System.Threading.Tasks;
 using Grpc.Core;
@@ -268,13 +269,28 @@ namespace Grpc.Core.Tests
             }
         }
 
+        [Test]
+        public void UserAgentStringPresent()
+        {
+            var internalCall = new Call<string, string>(ServiceName, EchoMethod, channel, Metadata.Empty);
+            string userAgent = Calls.BlockingUnaryCall(internalCall, "RETURN-USER-AGENT", CancellationToken.None);
+            Assert.IsTrue(userAgent.StartsWith("grpc-csharp/"));
+        }
+
         private static async Task<string> EchoHandler(string request, ServerCallContext context)
         {
             foreach (Metadata.Entry metadataEntry in context.RequestHeaders)
             {
-                Console.WriteLine("Echoing header " + metadataEntry.Key + " as trailer");
+                if (metadataEntry.Key != "user-agent")
+                {
                     context.ResponseTrailers.Add(metadataEntry);
                 }
+            }
+
+            if (request == "RETURN-USER-AGENT")
+            {
+                return context.RequestHeaders.Where(entry => entry.Key == "user-agent").Single().Value;
+            }
 
             if (request == "THROW")
             {

src/csharp/Grpc.Core/Channel.cs

@@ -28,11 +28,14 @@
 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #endregion
+
 using System;
 using System.Collections.Generic;
+using System.Linq;
 using System.Runtime.InteropServices;
 using System.Threading;
 using System.Threading.Tasks;
+
 using Grpc.Core.Internal;
 
 namespace Grpc.Core
@@ -44,6 +47,7 @@ namespace Grpc.Core
     {
         readonly GrpcEnvironment environment;
         readonly ChannelSafeHandle handle;
+        readonly List<ChannelOption> options;
         readonly string target;
         bool disposed;
 
@@ -57,7 +61,10 @@ namespace Grpc.Core
         public Channel(string host, Credentials credentials = null, IEnumerable<ChannelOption> options = null)
         {
             this.environment = GrpcEnvironment.GetInstance();
-            using (ChannelArgsSafeHandle nativeChannelArgs = ChannelOptions.CreateChannelArgs(options))
+            this.options = options != null ? new List<ChannelOption>(options) : new List<ChannelOption>();
+
+            EnsureUserAgentChannelOption(this.options);
+            using (ChannelArgsSafeHandle nativeChannelArgs = ChannelOptions.CreateChannelArgs(this.options))
             {
                 if (credentials != null)
                 {
@@ -71,7 +78,7 @@ namespace Grpc.Core
                     this.handle = ChannelSafeHandle.Create(host, nativeChannelArgs);
                 }
             }
-            this.target = GetOverridenTarget(host, options);
+            this.target = GetOverridenTarget(host, this.options);
         }
 
         /// <summary>
@@ -141,6 +148,20 @@ namespace Grpc.Core
             }
         }
 
+        private static void EnsureUserAgentChannelOption(List<ChannelOption> options)
+        {
+            if (!options.Any((option) => option.Name == ChannelOptions.PrimaryUserAgentString))
+            {
+                options.Add(new ChannelOption(ChannelOptions.PrimaryUserAgentString, GetUserAgentString()));
+            }
+        }
+
+        private static string GetUserAgentString()
+        {
+            // TODO(jtattermusch): it would be useful to also provide .NET/mono version.
+            return string.Format("grpc-csharp/{0}", VersionInfo.CurrentVersion);
+        }
+
         /// <summary>
         /// Look for SslTargetNameOverride option and return its value instead of originalTarget
         /// if found.

src/csharp/Grpc.Core/ChannelOptions.cs

@@ -115,41 +115,49 @@ namespace Grpc.Core
         }
     }
 
+    /// <summary>
+    /// Defines names of supported channel options.
+    /// </summary>
     public static class ChannelOptions
     {
-        // Override SSL target check. Only to be used for testing.
+        /// <summary>Override SSL target check. Only to be used for testing.</summary>
         public const string SslTargetNameOverride = "grpc.ssl_target_name_override";
 
-        // Enable census for tracing and stats collection
+        /// <summary>Enable census for tracing and stats collection</summary>
         public const string Census = "grpc.census";
 
-        // Maximum number of concurrent incoming streams to allow on a http2 connection
+        /// <summary>Maximum number of concurrent incoming streams to allow on a http2 connection</summary>
         public const string MaxConcurrentStreams = "grpc.max_concurrent_streams";
 
-        // Maximum message length that the channel can receive
+        /// <summary>Maximum message length that the channel can receive</summary>
         public const string MaxMessageLength = "grpc.max_message_length";
 
-        // Initial sequence number for http2 transports
+        /// <summary>Initial sequence number for http2 transports</summary>
         public const string Http2InitialSequenceNumber = "grpc.http2.initial_sequence_number";
 
+        /// <summary>Primary user agent: goes at the start of the user-agent metadata</summary>
+        public const string PrimaryUserAgentString = "grpc.primary_user_agent";
+
+        /// <summary> Secondary user agent: goes at the end of the user-agent metadata</summary>
+        public const string SecondaryUserAgentString = "grpc.secondary_user_agent";
+
         /// <summary>
         /// Creates native object for a collection of channel options.
         /// </summary>
         /// <returns>The native channel arguments.</returns>
-        internal static ChannelArgsSafeHandle CreateChannelArgs(IEnumerable<ChannelOption> options)
+        internal static ChannelArgsSafeHandle CreateChannelArgs(List<ChannelOption> options)
         {
-            if (options == null)
+            if (options == null || options.Count == 0)
             {
                 return ChannelArgsSafeHandle.CreateNull();
             }
-            var optionList = new List<ChannelOption>(options);  // It's better to do defensive copy
             ChannelArgsSafeHandle nativeArgs = null;
             try
             {
-                nativeArgs = ChannelArgsSafeHandle.Create(optionList.Count);
-                for (int i = 0; i < optionList.Count; i++)
+                nativeArgs = ChannelArgsSafeHandle.Create(options.Count);
+                for (int i = 0; i < options.Count; i++)
                 {
-                    var option = optionList[i];
+                    var option = options[i];
                     if (option.Type == ChannelOption.OptionType.Integer)
                     {
                         nativeArgs.SetInteger(i, option.Name, option.IntValue);

src/csharp/Grpc.Core/Grpc.Core.csproj

@@ -102,6 +102,7 @@
     <Compile Include="Internal\BatchContextSafeHandle.cs" />
     <Compile Include="ChannelOptions.cs" />
     <Compile Include="AsyncUnaryCall.cs" />
+    <Compile Include="VersionInfo.cs" />
   </ItemGroup>
   <ItemGroup>
     <None Include="Grpc.Core.nuspec" />

src/csharp/Grpc.Core/Server.cs

@@ -53,6 +53,7 @@ namespace Grpc.Core
         public const int PickUnusedPort = 0;
 
         readonly GrpcEnvironment environment;
+        readonly List<ChannelOption> options;
         readonly ServerSafeHandle handle;
         readonly object myLock = new object();
 
@@ -69,7 +70,8 @@ namespace Grpc.Core
         public Server(IEnumerable<ChannelOption> options = null)
         {
             this.environment = GrpcEnvironment.GetInstance();
-            using (var channelArgs = ChannelOptions.CreateChannelArgs(options))
+            this.options = options != null ? new List<ChannelOption>(options) : new List<ChannelOption>();
+            using (var channelArgs = ChannelOptions.CreateChannelArgs(this.options))
             {
                 this.handle = ServerSafeHandle.NewServer(environment.CompletionQueue, channelArgs);
             }

src/csharp/Grpc.Core/Version.cs

@@ -2,4 +2,4 @@ using System.Reflection;
 using System.Runtime.CompilerServices;
 
 // The current version of gRPC C#.
-[assembly: AssemblyVersion("0.6.0.*")]
+[assembly: AssemblyVersion(Grpc.Core.VersionInfo.CurrentVersion + ".*")]

src/csharp/Grpc.Core/VersionInfo.cs

@@ -0,0 +1,15 @@
+using System.Reflection;
+using System.Runtime.CompilerServices;
+
+namespace Grpc.Core
+{
+    public static class VersionInfo
+    {
+        /// <summary>
+        /// Current version of gRPC
+        /// </summary>
+        public const string CurrentVersion = "0.6.0";
+    }
+}
+
+

src/csharp/Grpc.IntegrationTesting.Client/Grpc.IntegrationTesting.Client.csproj

@@ -3,8 +3,6 @@
   <PropertyGroup>
     <Configuration Condition=" '$(Configuration)' == '' ">Debug</Configuration>
     <Platform Condition=" '$(Platform)' == '' ">x86</Platform>
-    <ProductVersion>10.0.0</ProductVersion>
-    <SchemaVersion>2.0</SchemaVersion>
     <ProjectGuid>{3D166931-BA2D-416E-95A3-D36E8F6E90B9}</ProjectGuid>
     <OutputType>Exe</OutputType>
     <RootNamespace>Grpc.IntegrationTesting.Client</RootNamespace>
@@ -48,6 +46,10 @@
       <Project>{C61154BA-DD4A-4838-8420-0162A28925E0}</Project>
       <Name>Grpc.IntegrationTesting</Name>
     </ProjectReference>
+    <ProjectReference Include="..\Grpc.Core\Grpc.Core.csproj">
+      <Project>{CCC4440E-49F7-4790-B0AF-FEABB0837AE7}</Project>
+      <Name>Grpc.Core</Name>
+    </ProjectReference>
   </ItemGroup>
   <ItemGroup>
     <None Include="app.config" />

src/csharp/Grpc.IntegrationTesting.Server/Grpc.IntegrationTesting.Server.csproj

@@ -3,8 +3,6 @@
   <PropertyGroup>
     <Configuration Condition=" '$(Configuration)' == '' ">Debug</Configuration>
     <Platform Condition=" '$(Platform)' == '' ">x86</Platform>
-    <ProductVersion>10.0.0</ProductVersion>
-    <SchemaVersion>2.0</SchemaVersion>
     <ProjectGuid>{A654F3B8-E859-4E6A-B30D-227527DBEF0D}</ProjectGuid>
     <OutputType>Exe</OutputType>
     <RootNamespace>Grpc.IntegrationTesting.Server</RootNamespace>
@@ -48,6 +46,10 @@
       <Project>{C61154BA-DD4A-4838-8420-0162A28925E0}</Project>
       <Name>Grpc.IntegrationTesting</Name>
     </ProjectReference>
+    <ProjectReference Include="..\Grpc.Core\Grpc.Core.csproj">
+      <Project>{CCC4440E-49F7-4790-B0AF-FEABB0837AE7}</Project>
+      <Name>Grpc.Core</Name>
+    </ProjectReference>
   </ItemGroup>
   <ItemGroup>
     <None Include="app.config" />