Migrate the Polly resilience sample into CodeMazeGuides on .NET 10 and Polly 8

dotnet-client-libraries/README.md

@@ -58,3 +58,4 @@ This section contains the topics about the client libraries in .NET.
 - [Multi-Source Data Integration With Strawberry Shake Subscriptions](https://code-maze.com/dotnetcore-multi-source-data-integration-with-strawberry-shake-subscriptions/)
 - [Introduction to the Wolverine Library in .NET](https://code-maze.com/dotnet-wolverine-library/)
 - [Comparison of Rebus, NServiceBus, and MassTransit in .NET](https://code-maze.com/aspnetcore-comparison-of-rebus-nservicebus-and-masstransit/)
+- [Polly in .NET: Retry, Circuit Breaker, and Fallback](https://code-maze.com/creating-resilient-microservices-in-net-with-polly/)

dotnet-client-libraries/ResilienceWithPolly/FinishedCode/AuthorsService/AuthorsService.csproj

@@ -0,0 +1,9 @@
+<Project Sdk="Microsoft.NET.Sdk.Web">
+
+  <PropertyGroup>
+    <TargetFramework>net10.0</TargetFramework>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+  </PropertyGroup>
+
+</Project>

dotnet-client-libraries/ResilienceWithPolly/FinishedCode/AuthorsService/Controllers/AuthorsController.cs

@@ -0,0 +1,13 @@
+using AuthorsService.Data;
+using AuthorsService.Models;
+using Microsoft.AspNetCore.Mvc;
+
+namespace AuthorsService.Controllers;
+
+[ApiController]
+[Route("[controller]")]
+public class AuthorsController(Repository repository) : ControllerBase
+{
+    [HttpGet]
+    public Task<IEnumerable<Author>> Get() => repository.GetAuthorsAsync();
+}

dotnet-client-libraries/ResilienceWithPolly/FinishedCode/AuthorsService/Data/Repository.cs

@@ -0,0 +1,34 @@
+using AuthorsService.Models;
+
+namespace AuthorsService.Data;
+
+public class Repository
+{
+    private readonly IEnumerable<Author> _authors =
+    [
+        new Author { AuthorId = 1, Name = "John Doe", Country = "Australia" },
+        new Author { AuthorId = 2, Name = "Jane Smith", Country = "United States" }
+    ];
+
+    private readonly DateTime _startTime = DateTime.UtcNow;
+    private bool _shouldFail = true;
+
+    public async Task<IEnumerable<Author>> GetAuthorsAsync()
+    {
+        if (_shouldFail)
+        {
+            _shouldFail = false;
+
+            throw new InvalidOperationException("Oops!");
+        }
+
+        if (_startTime.AddMinutes(1) > DateTime.UtcNow)
+        {
+            await Task.Delay(TimeSpan.FromSeconds(5));
+
+            throw new TimeoutException("Timeout!");
+        }
+
+        return _authors;
+    }
+}

dotnet-client-libraries/ResilienceWithPolly/FinishedCode/AuthorsService/Models/Author.cs

@@ -0,0 +1,8 @@
+namespace AuthorsService.Models;
+
+public class Author
+{
+    public int AuthorId { get; set; }
+    public required string Name { get; set; }
+    public required string Country { get; set; }
+}

dotnet-client-libraries/ResilienceWithPolly/FinishedCode/AuthorsService/Program.cs

@@ -0,0 +1,13 @@
+using AuthorsService.Data;
+
+var builder = WebApplication.CreateBuilder(args);
+
+builder.Services.AddSingleton<Repository>();
+builder.Services.AddControllers();
+
+var app = builder.Build();
+
+app.UseHttpsRedirection();
+app.MapControllers();
+
+app.Run();

dotnet-client-libraries/ResilienceWithPolly/FinishedCode/AuthorsService/Properties/launchSettings.json

@@ -0,0 +1,14 @@
+{
+  "$schema": "http://json.schemastore.org/launchsettings.json",
+  "profiles": {
+    "AuthorsService": {
+      "commandName": "Project",
+      "launchBrowser": true,
+      "launchUrl": "",
+      "applicationUrl": "https://localhost:5001;http://localhost:5000",
+      "environmentVariables": {
+        "ASPNETCORE_ENVIRONMENT": "Development"
+      }
+    }
+  }
+}

dotnet-client-libraries/ResilienceWithPolly/FinishedCode/AuthorsService/appsettings.Development.json

@@ -0,0 +1,9 @@
+{
+  "Logging": {
+    "LogLevel": {
+      "Default": "Information",
+      "Microsoft": "Warning",
+      "Microsoft.Hosting.Lifetime": "Information"
+    }
+  }
+}

dotnet-client-libraries/ResilienceWithPolly/FinishedCode/AuthorsService/appsettings.json

@@ -0,0 +1,10 @@
+{
+  "Logging": {
+    "LogLevel": {
+      "Default": "Information",
+      "Microsoft": "Warning",
+      "Microsoft.Hosting.Lifetime": "Information"
+    }
+  },
+  "AllowedHosts": "*"
+}

dotnet-client-libraries/ResilienceWithPolly/FinishedCode/BooksService/BooksService.csproj

@@ -0,0 +1,9 @@
+<Project Sdk="Microsoft.NET.Sdk.Web">
+
+  <PropertyGroup>
+    <TargetFramework>net10.0</TargetFramework>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+  </PropertyGroup>
+
+</Project>

dotnet-client-libraries/ResilienceWithPolly/FinishedCode/BooksService/Controllers/BooksController.cs

@@ -0,0 +1,13 @@
+using BooksService.Data;
+using BooksService.Models;
+using Microsoft.AspNetCore.Mvc;
+
+namespace BooksService.Controllers;
+
+[ApiController]
+[Route("[controller]")]
+public class BooksController(Repository repository) : ControllerBase
+{
+    [HttpGet]
+    public IEnumerable<Book> Get() => repository.GetBooks();
+}

dotnet-client-libraries/ResilienceWithPolly/FinishedCode/BooksService/Data/Repository.cs

@@ -0,0 +1,15 @@
+using BooksService.Models;
+
+namespace BooksService.Data;
+
+public class Repository
+{
+    private readonly IEnumerable<Book> _books =
+    [
+        new Book { BookId = 1, AuthorId = 1, Name = "The Fallen Shore", NumberOfPages = 123 },
+        new Book { BookId = 2, AuthorId = 1, Name = "Harmony of Joy", NumberOfPages = 211 },
+        new Book { BookId = 3, AuthorId = 2, Name = "Aliens vs Robots", NumberOfPages = 345 }
+    ];
+
+    public IEnumerable<Book> GetBooks() => _books;
+}

dotnet-client-libraries/ResilienceWithPolly/FinishedCode/BooksService/Models/Book.cs

@@ -0,0 +1,9 @@
+namespace BooksService.Models;
+
+public class Book
+{
+    public int BookId { get; set; }
+    public int AuthorId { get; set; }
+    public required string Name { get; set; }
+    public int NumberOfPages { get; set; }
+}

dotnet-client-libraries/ResilienceWithPolly/FinishedCode/BooksService/Program.cs

@@ -0,0 +1,13 @@
+using BooksService.Data;
+
+var builder = WebApplication.CreateBuilder(args);
+
+builder.Services.AddSingleton<Repository>();
+builder.Services.AddControllers();
+
+var app = builder.Build();
+
+app.UseHttpsRedirection();
+app.MapControllers();
+
+app.Run();

dotnet-client-libraries/ResilienceWithPolly/FinishedCode/BooksService/Properties/launchSettings.json

@@ -0,0 +1,14 @@
+{
+  "$schema": "http://json.schemastore.org/launchsettings.json",
+  "profiles": {
+    "BooksService": {
+      "commandName": "Project",
+      "launchBrowser": true,
+      "launchUrl": "",
+      "applicationUrl": "https://localhost:6001;http://localhost:6000",
+      "environmentVariables": {
+        "ASPNETCORE_ENVIRONMENT": "Development"
+      }
+    }
+  }
+}

dotnet-client-libraries/ResilienceWithPolly/FinishedCode/BooksService/appsettings.Development.json

@@ -0,0 +1,9 @@
+{
+  "Logging": {
+    "LogLevel": {
+      "Default": "Information",
+      "Microsoft": "Warning",
+      "Microsoft.Hosting.Lifetime": "Information"
+    }
+  }
+}

dotnet-client-libraries/ResilienceWithPolly/FinishedCode/BooksService/appsettings.json

@@ -0,0 +1,10 @@
+{
+  "Logging": {
+    "LogLevel": {
+      "Default": "Information",
+      "Microsoft": "Warning",
+      "Microsoft.Hosting.Lifetime": "Information"
+    }
+  },
+  "AllowedHosts": "*"
+}

dotnet-client-libraries/ResilienceWithPolly/FinishedCode/Monolith/Monolith.csproj

@@ -0,0 +1,13 @@
+<Project Sdk="Microsoft.NET.Sdk.Web">
+
+  <PropertyGroup>
+    <TargetFramework>net10.0</TargetFramework>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="Polly.Extensions" Version="8.7.0" />
+  </ItemGroup>
+
+</Project>

dotnet-client-libraries/ResilienceWithPolly/FinishedCode/Monolith/Program.cs

@@ -0,0 +1,21 @@
+using Microsoft.AspNetCore.Mvc;
+using Monolith.Resilience;
+using Polly;
+
+var builder = WebApplication.CreateBuilder(args);
+
+builder.Services.AddCors(options => options.AddDefaultPolicy(policy => policy.AllowAnyOrigin()));
+builder.Services.AddHttpClient();
+builder.Services.AddControllers();
+
+builder.Services.AddResiliencePipeline<string, IActionResult>(
+    ProxyPipeline.Name,
+    (pipeline, _) => ProxyPipeline.Configure(pipeline));
+
+var app = builder.Build();
+
+app.UseHttpsRedirection();
+app.UseCors();
+app.MapControllers();
+
+app.Run();

dotnet-client-libraries/ResilienceWithPolly/FinishedCode/Monolith/Properties/launchSettings.json

@@ -0,0 +1,14 @@
+{
+  "$schema": "http://json.schemastore.org/launchsettings.json",  
+  "profiles": {    
+    "Monolith": {
+      "commandName": "Project",
+      "launchBrowser": true,
+      "launchUrl": "",
+      "applicationUrl": "https://localhost:7001",
+      "environmentVariables": {
+        "ASPNETCORE_ENVIRONMENT": "Development"
+      }
+    }
+  }
+}

dotnet-client-libraries/ResilienceWithPolly/FinishedCode/Monolith/ProxyController.cs

@@ -0,0 +1,32 @@
+using Microsoft.AspNetCore.Mvc;
+using Monolith.Resilience;
+using Polly;
+using Polly.Registry;
+
+namespace Monolith;
+
+[Route("[action]")]
+[ApiController]
+public class ProxyController : ControllerBase
+{
+    private readonly HttpClient _httpClient;
+    private readonly ResiliencePipeline<IActionResult> _pipeline;
+
+    public ProxyController(IHttpClientFactory httpClientFactory,
+        ResiliencePipelineProvider<string> pipelineProvider)
+    {
+        _httpClient = httpClientFactory.CreateClient();
+        _pipeline = pipelineProvider.GetPipeline<IActionResult>(ProxyPipeline.Name);
+    }
+
+    [HttpGet]
+    public Task<IActionResult> Books() => ProxyTo("https://localhost:6001/books");
+
+    [HttpGet]
+    public Task<IActionResult> Authors() => ProxyTo("https://localhost:5001/authors");
+
+    private async Task<IActionResult> ProxyTo(string url)
+        => await _pipeline.ExecuteAsync(
+            async token => (IActionResult)Content(await _httpClient.GetStringAsync(url, token)),
+            HttpContext.RequestAborted);
+}

dotnet-client-libraries/ResilienceWithPolly/FinishedCode/Monolith/Resilience/ProxyPipeline.cs

@@ -0,0 +1,38 @@
+using Microsoft.AspNetCore.Mvc;
+using Polly;
+using Polly.CircuitBreaker;
+using Polly.Fallback;
+using Polly.Retry;
+
+namespace Monolith.Resilience;
+
+public static class ProxyPipeline
+{
+    public const string Name = "proxy";
+
+    public const string FallbackMessage =
+        "Sorry, we are currently experiencing issues. Please try again later";
+
+    public static void Configure(ResiliencePipelineBuilder<IActionResult> builder) =>
+        builder
+            .AddFallback(new FallbackStrategyOptions<IActionResult>
+            {
+                ShouldHandle = new PredicateBuilder<IActionResult>().Handle<Exception>(),
+                FallbackAction = static _ => Outcome.FromResultAsValueTask<IActionResult>(
+                    new ContentResult { Content = FallbackMessage })
+            })
+            .AddRetry(new RetryStrategyOptions<IActionResult>
+            {
+                ShouldHandle = new PredicateBuilder<IActionResult>().Handle<Exception>(),
+                MaxRetryAttempts = 1,
+                Delay = TimeSpan.Zero
+            })
+            .AddCircuitBreaker(new CircuitBreakerStrategyOptions<IActionResult>
+            {
+                ShouldHandle = new PredicateBuilder<IActionResult>().Handle<Exception>(),
+                FailureRatio = 1.0,
+                MinimumThroughput = 2,
+                SamplingDuration = TimeSpan.FromSeconds(30),
+                BreakDuration = TimeSpan.FromMinutes(1)
+            });
+}

dotnet-client-libraries/ResilienceWithPolly/FinishedCode/Monolith/appsettings.Development.json

@@ -0,0 +1,9 @@
+{
+  "Logging": {
+    "LogLevel": {
+      "Default": "Information",
+      "Microsoft": "Warning",
+      "Microsoft.Hosting.Lifetime": "Information"
+    }
+  }
+}

dotnet-client-libraries/ResilienceWithPolly/FinishedCode/Monolith/appsettings.json

@@ -0,0 +1,10 @@
+{
+  "Logging": {
+    "LogLevel": {
+      "Default": "Information",
+      "Microsoft": "Warning",
+      "Microsoft.Hosting.Lifetime": "Information"
+    }
+  },
+  "AllowedHosts": "*"
+}

dotnet-client-libraries/ResilienceWithPolly/FinishedCode/consumer.html

@@ -0,0 +1,21 @@
+<html>
+	<head></head>
+	<body>
+		<button onclick="callAPI('books')">Get Books</button>
+		<button onclick="callAPI('authors')">Get Authors</button>
+	</body>
+	<script type="text/javascript">
+	function callAPI(path) {
+		let request = new XMLHttpRequest();
+		request.open("GET", "https://localhost:7001/" + path);
+		request.send();
+		request.onload = () => {
+			if (request.status === 200) {
+				alert(request.response);
+			} else {
+				alert(`Error: ${request.status} ${request.responseText}`);
+			}
+		}
+	}
+	</script>
+</html>