Add retrier example app (#1284)

examples/README.md

@@ -260,3 +260,11 @@ Code-first is a good choice if an app is written entirely in .NET. Code contract
 * Configure [protobuf-net.Grpc](https://github.com/protobuf-net/protobuf-net.Grpc)
 * Create a code-first gRPC service
 * Create a code-first gRPC client
+
+## [Retrier](./Retrier)
+
+The retrier example shows how to configure a client to use gRPC retries to retry failed calls. gRPC retries enables resilient, fault tolerant gRPC apps in .NET.
+
+##### Scenarios:
+
+* Configure [gRPC retires](https://docs.microsoft.com/aspnet/core/grpc/retries)

examples/Retrier/Client/Client.csproj

@@ -0,0 +1,16 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net5.0</TargetFramework>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <Protobuf Include="..\Proto\retry.proto" GrpcServices="Client" Link="Protos\retry.proto" />
+
+    <PackageReference Include="Grpc.Net.Client" Version="$(GrpcDotNetPackageVersion)" />
+    <PackageReference Include="Google.Protobuf" Version="$(GoogleProtobufPackageVersion)" />
+    <PackageReference Include="Grpc.Tools" Version="$(GrpcPackageVersion)" PrivateAssets="All" />
+  </ItemGroup>
+
+</Project>

examples/Retrier/Client/Program.cs

@@ -0,0 +1,125 @@
+#region Copyright notice and license
+
+// Copyright 2019 The 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.Threading.Tasks;
+using Grpc.Core;
+using Grpc.Net.Client;
+using Grpc.Net.Client.Configuration;
+using Retry;
+
+namespace Client
+{
+    public class Program
+    {
+        static async Task Main(string[] args)
+        {
+            using var channel = CreateChannel();
+            var client = new Retrier.RetrierClient(channel);
+
+            await UnaryRetry(client);
+
+            Console.WriteLine("Shutting down");
+            Console.WriteLine("Press any key to exit...");
+            Console.ReadKey();
+        }
+
+        private static async Task UnaryRetry(Retrier.RetrierClient client)
+        {
+            Console.WriteLine("Delivering packages...");
+            foreach (var product in Products)
+            {
+                try
+                {
+                    var package = new Package { Name = product };
+                    var call = client.DeliverPackageAsync(package);
+                    var response = await call;
+
+                    #region Print success
+                    Console.ForegroundColor = ConsoleColor.Green;
+                    Console.Write(response.Message);
+                    Console.ResetColor();
+                    Console.Write(" " + await GetRetryCount(call.ResponseHeadersAsync));
+                    Console.WriteLine();
+                    #endregion
+                }
+                catch (RpcException ex)
+                {
+                    #region Print failure
+                    Console.ForegroundColor = ConsoleColor.Red;
+                    Console.WriteLine(ex.Status.Detail);
+                    Console.ResetColor();
+                    #endregion
+                }
+
+                await Task.Delay(TimeSpan.FromSeconds(0.2));
+            }
+        }
+
+        private static GrpcChannel CreateChannel()
+        {
+            var methodConfig = new MethodConfig
+            {
+                Names = { MethodName.Default },
+                RetryPolicy = new RetryPolicy
+                {
+                    MaxAttempts = 10,
+                    InitialBackoff = TimeSpan.FromSeconds(0.5),
+                    MaxBackoff = TimeSpan.FromSeconds(0.5),
+                    BackoffMultiplier = 1,
+                    RetryableStatusCodes = { StatusCode.Unavailable }
+                }
+            };
+
+            return GrpcChannel.ForAddress("http://localhost:5000", new GrpcChannelOptions
+            {
+                ServiceConfig = new ServiceConfig { MethodConfigs = { methodConfig } }
+            });
+        }
+
+        private static async Task<string> GetRetryCount(Task<Metadata> responseHeadersTask)
+        {
+            var headers = await responseHeadersTask;
+            var previousAttemptCount = headers.GetValue("grpc-previous-rpc-attempts");
+            return previousAttemptCount != null ? $"(retry count: {previousAttemptCount})" : string.Empty;
+        }
+
+        private static readonly IList<string> Products = new List<string>
+        {
+            "Secrets of Silicon Valley",
+            "The Busy Executive's Database Guide",
+            "Emotional Security: A New Algorithm",
+            "Prolonged Data Deprivation: Four Case Studies",
+            "Cooking with Computers: Surreptitious Balance Sheets",
+            "Silicon Valley Gastronomic Treats",
+            "Sushi, Anyone?",
+            "Fifty Years in Buckingham Palace Kitchens",
+            "But Is It User Friendly?",
+            "You Can Combat Computer Stress!",
+            "Is Anger the Enemy?",
+            "Life Without Fear",
+            "The Gourmet Microwave",
+            "Onions, Leeks, and Garlic: Cooking Secrets of the Mediterranean",
+            "The Psychology of Computer Cooking",
+            "Straight Talk About Computers",
+            "Computer Phobic AND Non-Phobic Individuals: Behavior Variations",
+            "Net Etiquette"
+        };
+    }
+}

examples/Retrier/Proto/retry.proto

@@ -0,0 +1,31 @@
+// Copyright 2019 The 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.
+
+syntax = "proto3";
+
+import "google/protobuf/wrappers.proto";
+
+package retry;
+
+service Retrier {
+  rpc DeliverPackage (Package) returns (Response);
+}
+
+message Package {
+  string name = 1;
+}
+
+message Response {
+  string message = 1;
+}

examples/Retrier/Retrier.sln

@@ -0,0 +1,31 @@
+
+Microsoft Visual Studio Solution File, Format Version 12.00
+# Visual Studio Version 16
+VisualStudioVersion = 16.0.29230.61
+MinimumVisualStudioVersion = 10.0.40219.1
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Server", "Server\Server.csproj", "{534AC5F8-2DF2-40BD-87A5-B3D8310118C4}"
+EndProject
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Client", "Client\Client.csproj", "{48A1D3BC-A14B-436A-8822-6DE2BEF8B747}"
+EndProject
+Global
+	GlobalSection(SolutionConfigurationPlatforms) = preSolution
+		Debug|Any CPU = Debug|Any CPU
+		Release|Any CPU = Release|Any CPU
+	EndGlobalSection
+	GlobalSection(ProjectConfigurationPlatforms) = postSolution
+		{534AC5F8-2DF2-40BD-87A5-B3D8310118C4}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{534AC5F8-2DF2-40BD-87A5-B3D8310118C4}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{534AC5F8-2DF2-40BD-87A5-B3D8310118C4}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{534AC5F8-2DF2-40BD-87A5-B3D8310118C4}.Release|Any CPU.Build.0 = Release|Any CPU
+		{48A1D3BC-A14B-436A-8822-6DE2BEF8B747}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{48A1D3BC-A14B-436A-8822-6DE2BEF8B747}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{48A1D3BC-A14B-436A-8822-6DE2BEF8B747}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{48A1D3BC-A14B-436A-8822-6DE2BEF8B747}.Release|Any CPU.Build.0 = Release|Any CPU
+	EndGlobalSection
+	GlobalSection(SolutionProperties) = preSolution
+		HideSolutionNode = FALSE
+	EndGlobalSection
+	GlobalSection(ExtensibilityGlobals) = postSolution
+		SolutionGuid = {D22B3129-3BFB-41FA-9FCE-E45EBEF8C2DD}
+	EndGlobalSection
+EndGlobal

examples/Retrier/Server/Program.cs

@@ -0,0 +1,38 @@
+#region Copyright notice and license
+
+// Copyright 2019 The 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 Microsoft.AspNetCore.Hosting;
+using Microsoft.Extensions.Hosting;
+
+namespace Server
+{
+    public class Program
+    {
+        public static void Main(string[] args)
+        {
+            CreateHostBuilder(args).Build().Run();
+        }
+
+        public static IHostBuilder CreateHostBuilder(string[] args) =>
+            Host.CreateDefaultBuilder(args)
+                .ConfigureWebHostDefaults(webBuilder =>
+                {
+                    webBuilder.UseStartup<Startup>();
+                });
+    }
+}

examples/Retrier/Server/Server.csproj

@@ -0,0 +1,13 @@
+<Project Sdk="Microsoft.NET.Sdk.Web">
+
+  <PropertyGroup>
+    <TargetFramework>net5.0</TargetFramework>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <Protobuf Include="..\Proto\retry.proto" GrpcServices="Server" Link="Protos\retry.proto" />
+
+    <PackageReference Include="Grpc.AspNetCore" Version="$(GrpcDotNetPackageVersion)" />
+  </ItemGroup>
+
+</Project>

examples/Retrier/Server/Services/RetrierService.cs

@@ -0,0 +1,44 @@
+#region Copyright notice and license
+
+// Copyright 2019 The 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.Threading.Tasks;
+using Grpc.Core;
+using Retry;
+
+namespace Server
+{
+    public class RetrierService : Retrier.RetrierBase
+    {
+        private readonly Random _random = new Random();
+
+        public override Task<Response> DeliverPackage(Package request, ServerCallContext context)
+        {
+            const double deliveryChance = 0.5;
+            if (_random.NextDouble() > deliveryChance)
+            {
+                throw new RpcException(new Status(StatusCode.Unavailable, $"- {request.Name}"));
+            }
+
+            return Task.FromResult(new Response
+            {
+                Message = $"+ {request.Name}"
+            });
+        }
+    }
+}

examples/Retrier/Server/Startup.cs

@@ -0,0 +1,48 @@
+#region Copyright notice and license
+
+// Copyright 2019 The 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 Microsoft.AspNetCore.Builder;
+using Microsoft.AspNetCore.Hosting;
+using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.Hosting;
+
+namespace Server
+{
+    public class Startup
+    {
+        public void ConfigureServices(IServiceCollection services)
+        {
+            services.AddGrpc();
+        }
+
+        public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
+        {
+            if (env.IsDevelopment())
+            {
+                app.UseDeveloperExceptionPage();
+            }
+
+            app.UseRouting();
+
+            app.UseEndpoints(endpoints =>
+            {
+                endpoints.MapGrpcService<RetrierService>();
+            });
+        }
+    }
+}

examples/Retrier/Server/appsettings.Development.json

@@ -0,0 +1,10 @@
+{
+  "Logging": {
+    "LogLevel": {
+      "Default": "Debug",
+      "System": "Information",
+      "Grpc": "Information",
+      "Microsoft": "Information"
+    }
+  }
+}

examples/Retrier/Server/appsettings.json

@@ -0,0 +1,13 @@
+{
+  "Logging": {
+    "LogLevel": {
+      "Default": "Information"
+    }
+  },
+  "AllowedHosts": "*",
+  "Kestrel": {
+    "EndpointDefaults": {
+      "Protocols": "Http2"
+    }
+  }
+}