Improve gRPC channel and client debugging (#2196)

src/Grpc.Core.Api/ClientBase.cs

@@ -17,6 +17,8 @@
 #endregion
 
 using System;
+using System.Collections.Generic;
+using System.Diagnostics;
 using Grpc.Core.Interceptors;
 using Grpc.Core.Internal;
 using Grpc.Core.Utils;
@@ -84,6 +86,10 @@ public T WithHost(string host)
 /// <summary>
 /// Base class for client-side stubs.
 /// </summary>
+// The call invoker's debug information is specified in DebuggerDisplayAttribute.
+// It can't be concatenated inside ServiceNameDebuggerToString() because it isn't available in ToString.
+[DebuggerDisplay("{ServiceNameDebuggerToString(),nq}{CallInvoker}")]
+[DebuggerTypeProxy(typeof(ClientBaseDebugType))]
 public abstract class ClientBase
 {
     readonly ClientBaseConfiguration configuration;
@@ -141,6 +147,31 @@ internal ClientBaseConfiguration Configuration
         get { return this.configuration; }
     }
 
+    internal string ServiceNameDebuggerToString()
+    {
+        var serviceName = ClientDebuggerHelpers.GetServiceName(GetType());
+        if (serviceName == null)
+        {
+            return string.Empty;
+        }
+
+        return $@"Service = ""{serviceName}"", ";
+    }
+
+    internal sealed class ClientBaseDebugType
+    {
+        readonly ClientBase client;
+
+        public ClientBaseDebugType(ClientBase client)
+        {
+            this.client = client;
+        }
+
+        public CallInvoker CallInvoker => client.CallInvoker;
+        public string? Service => ClientDebuggerHelpers.GetServiceName(client.GetType());
+        public List<IMethod>? Methods => ClientDebuggerHelpers.GetServiceMethods(client.GetType());
+    }
+
     /// <summary>
     /// Represents configuration of ClientBase. The class itself is visible to
     /// subclasses, but contents are marked as internal to make the instances opaque.

src/Grpc.Core.Api/Interceptors/InterceptingCallInvoker.cs

@@ -17,6 +17,7 @@
 #endregion
 
 using System;
+using System.Diagnostics;
 using Grpc.Core.Utils;
 
 namespace Grpc.Core.Interceptors;
@@ -25,6 +26,7 @@ namespace Grpc.Core.Interceptors;
 /// Decorates an underlying <see cref="Grpc.Core.CallInvoker" /> to
 /// intercept calls through a given interceptor.
 /// </summary>
+[DebuggerDisplay("{invoker}")]
 internal class InterceptingCallInvoker : CallInvoker
 {
     readonly CallInvoker invoker;

src/Grpc.Core.Api/Internal/ClientDebuggerHelpers.cs

@@ -0,0 +1,110 @@
+#region Copyright notice and license
+
+// Copyright 2015-2016 gRPC authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#endregion
+
+using System;
+using System.Collections.Generic;
+using System.Diagnostics.CodeAnalysis;
+using System.Reflection;
+
+namespace Grpc.Core.Internal;
+
+internal static class ClientDebuggerHelpers
+{
+#if NETSTANDARD1_5
+    private static TypeInfo? GetParentType(Type clientType)
+#else
+    private static Type? GetParentType(Type clientType)
+#endif
+    {
+        // Attempt to get the parent type for a generated client.
+        // A generated client is always nested inside a static type that contains information about the client.
+        // For example:
+        //
+        // public static class Greeter
+        // {
+        //     private static readonly serviceName = "Greeter";
+        //     private static readonly Method<HelloRequest, HelloReply> _sayHelloMethod;
+        //
+        //     public class GreeterClient { }
+        // }
+
+        if (!clientType.IsNested)
+        {
+            return null;
+        }
+
+#if NETSTANDARD1_5
+        var parentType = clientType.DeclaringType.GetTypeInfo();
+#else
+        var parentType = clientType.DeclaringType;
+#endif
+        // Check parent type is static. A C# static type is sealed and abstract.
+        if (parentType == null || (!parentType.IsSealed && !parentType.IsAbstract))
+        {
+            return null;
+        }
+
+        return parentType;
+    }
+
+    [UnconditionalSuppressMessage("Trimmer", "IL2075", Justification = "Only used by debugging. If trimming is enabled then missing data is not displayed in debugger.")]
+    internal static string? GetServiceName(Type clientType)
+    {
+        // Attempt to get the service name from the generated __ServiceName field.
+        // If the service name can't be resolved then it isn't displayed in the client's debugger display.
+        var parentType = GetParentType(clientType);
+        var field = parentType?.GetField("__ServiceName", BindingFlags.Static | BindingFlags.NonPublic);
+        if (field == null)
+        {
+            return null;
+        }
+
+        return field.GetValue(null)?.ToString();
+    }
+
+    [UnconditionalSuppressMessage("Trimmer", "IL2075", Justification = "Only used by debugging. If trimming is enabled then missing data is not displayed in debugger.")]
+    internal static List<IMethod>? GetServiceMethods(Type clientType)
+    {
+        // Attempt to get the service methods from generated method fields.
+        // If methods can't be resolved then the collection in the client type proxy is null.
+        var parentType = GetParentType(clientType);
+        if (parentType == null)
+        {
+            return null;
+        }
+
+        var methods = new List<IMethod>();
+
+        var fields = parentType.GetFields(BindingFlags.Static | BindingFlags.NonPublic);
+        foreach (var field in fields)
+        {
+            if (IsMethodField(field))
+            {
+                methods.Add((IMethod)field.GetValue(null));
+            }
+        }
+        return methods;
+
+        static bool IsMethodField(FieldInfo field) =>
+#if NETSTANDARD1_5
+            typeof(IMethod).GetTypeInfo().IsAssignableFrom(field.FieldType);
+#else
+            typeof(IMethod).IsAssignableFrom(field.FieldType);
+#endif
+    }
+}

src/Grpc.Core.Api/Method.cs

@@ -17,6 +17,7 @@
 #endregion
 
 using System;
+using System.Diagnostics;
 using Grpc.Core.Utils;
 
 namespace Grpc.Core;
@@ -71,6 +72,7 @@ public interface IMethod
 /// </summary>
 /// <typeparam name="TRequest">Request message type for this method.</typeparam>
 /// <typeparam name="TResponse">Response message type for this method.</typeparam>
+[DebuggerDisplay("Name = {Name}, ServiceName = {ServiceName}, Type = {Type}")]
 public class Method<TRequest, TResponse> : IMethod
 {
     readonly MethodType type;

src/Grpc.Core.Api/SslCredentials.cs

@@ -117,5 +117,3 @@ public override void InternalPopulateConfiguration(ChannelCredentialsConfigurato
 
     internal override bool IsComposable => true;
 }
-
-

src/Grpc.Net.Client/GrpcChannel.cs

@@ -38,6 +38,7 @@ namespace Grpc.Net.Client;
 /// Client objects can reuse the same channel. Creating a channel is an expensive operation compared to invoking
 /// a remote call so in general you should reuse a single channel for as many calls as possible.
 /// </summary>
+[DebuggerDisplay("{DebuggerToString(),nq}")]
 public sealed class GrpcChannel : ChannelBase, IDisposable
 {
     internal const int DefaultMaxReceiveMessageSize = 1024 * 1024 * 4; // 4 MB
@@ -845,6 +846,23 @@ public ISubchannelTransport Create(Subchannel subchannel)
     }
 #endif
 
+    internal string DebuggerToString()
+    {
+        var debugText = $@"Address = ""{Address.OriginalString}""";
+        if (!IsHttpOrHttpsAddress(Address))
+        {
+            // It is easy to tell whether a channel is secured when the address contains http/https.
+            // Load balancing use custom schemes. Include IsSecure in debug text for custom schemes.
+            // For example: Address = "dns:///my-dns-server, IsSecure = false
+            debugText += $", IsSecure = {(_isSecure ? "true" : "false")}";
+        }
+        if (Disposed)
+        {
+            debugText += ", Disposed = true";
+        }
+        return debugText;
+    }
+
     private readonly struct MethodKey : IEquatable<MethodKey>
     {
         public MethodKey(string? service, string? method)

src/Grpc.Net.Client/Internal/HttpClientCallInvoker.cs

@@ -26,6 +26,7 @@ namespace Grpc.Net.Client.Internal;
 /// <summary>
 /// A client-side RPC invocation using HttpClient.
 /// </summary>
+[DebuggerDisplay("{Channel}")]
 internal sealed class HttpClientCallInvoker : CallInvoker
 {
     internal GrpcChannel Channel { get; }

src/Shared/CodeAnalysisAttributes.cs

@@ -151,4 +151,84 @@ internal enum DynamicallyAccessedMemberTypes
     All = ~None
 }
 
+/// <summary>
+/// Suppresses reporting of a specific rule violation, allowing multiple suppressions on a
+/// single code artifact.
+/// </summary>
+/// <remarks>
+/// <see cref="UnconditionalSuppressMessageAttribute"/> is different than
+/// <see cref="SuppressMessageAttribute"/> in that it doesn't have a
+/// <see cref="ConditionalAttribute"/>. So it is always preserved in the compiled assembly.
+/// </remarks>
+[AttributeUsage(AttributeTargets.All, Inherited = false, AllowMultiple = true)]
+internal sealed class UnconditionalSuppressMessageAttribute : Attribute
+{
+    /// <summary>
+    /// Initializes a new instance of the <see cref="UnconditionalSuppressMessageAttribute"/>
+    /// class, specifying the category of the tool and the identifier for an analysis rule.
+    /// </summary>
+    /// <param name="category">The category for the attribute.</param>
+    /// <param name="checkId">The identifier of the analysis rule the attribute applies to.</param>
+    public UnconditionalSuppressMessageAttribute(string category, string checkId)
+    {
+        Category = category;
+        CheckId = checkId;
+    }
+
+    /// <summary>
+    /// Gets the category identifying the classification of the attribute.
+    /// </summary>
+    /// <remarks>
+    /// The <see cref="Category"/> property describes the tool or tool analysis category
+    /// for which a message suppression attribute applies.
+    /// </remarks>
+    public string Category { get; }
+
+    /// <summary>
+    /// Gets the identifier of the analysis tool rule to be suppressed.
+    /// </summary>
+    /// <remarks>
+    /// Concatenated together, the <see cref="Category"/> and <see cref="CheckId"/>
+    /// properties form a unique check identifier.
+    /// </remarks>
+    public string CheckId { get; }
+
+    /// <summary>
+    /// Gets or sets the scope of the code that is relevant for the attribute.
+    /// </summary>
+    /// <remarks>
+    /// The Scope property is an optional argument that specifies the metadata scope for which
+    /// the attribute is relevant.
+    /// </remarks>
+    public string? Scope { get; set; }
+
+    /// <summary>
+    /// Gets or sets a fully qualified path that represents the target of the attribute.
+    /// </summary>
+    /// <remarks>
+    /// The <see cref="Target"/> property is an optional argument identifying the analysis target
+    /// of the attribute. An example value is "System.IO.Stream.ctor():System.Void".
+    /// Because it is fully qualified, it can be long, particularly for targets such as parameters.
+    /// The analysis tool user interface should be capable of automatically formatting the parameter.
+    /// </remarks>
+    public string? Target { get; set; }
+
+    /// <summary>
+    /// Gets or sets an optional argument expanding on exclusion criteria.
+    /// </summary>
+    /// <remarks>
+    /// The <see cref="MessageId "/> property is an optional argument that specifies additional
+    /// exclusion where the literal metadata target is not sufficiently precise. For example,
+    /// the <see cref="UnconditionalSuppressMessageAttribute"/> cannot be applied within a method,
+    /// and it may be desirable to suppress a violation against a statement in the method that will
+    /// give a rule violation, but not against all statements in the method.
+    /// </remarks>
+    public string? MessageId { get; set; }
+
+    /// <summary>
+    /// Gets or sets the justification for suppressing the code analysis message.
+    /// </summary>
+    public string? Justification { get; set; }
+}
+
 #endif