Introduce IResilienceStrategy and core primitives for V8 (App-vNext#1056)

Author: martintmk

eng/analyzers/Stylecop.globalconfig

@@ -1529,7 +1529,7 @@ dotnet_diagnostic.SA1600.severity = warning
 # Title    : Partial elements should be documented
 # Category : StyleCop.CSharp.DocumentationRules
 # Help Link: https://github.com/DotNetAnalyzers/StyleCopAnalyzers/blob/master/documentation/SA1601.md
-dotnet_diagnostic.SA1601.severity = warning
+dotnet_diagnostic.SA1601.severity = none
 
 # Title    : Enumeration items should be documented
 # Category : StyleCop.CSharp.DocumentationRules

eng/stryker-config.json

@@ -11,6 +11,7 @@
       "ConfigureAwait",
       "Dispose",
       "LogError",
+      "Debug.Assert",
       "LogInformation"
     ],
     "ignore-mutations": [

src/Polly.Core.Tests/DelegatingResilienceStrategyTests.cs

@@ -0,0 +1,66 @@
+using FluentAssertions;
+using Polly.Core.Tests.Utils;
+using Xunit;
+
+namespace Polly.Core.Tests;
+
+public class DelegatingResilienceStrategyTests
+{
+    [Fact]
+    public void Next_Change_Ok()
+    {
+        var next = new TestResilienceStrategy();
+        var strategy = new TestResilienceStrategy
+        {
+            Next = next
+        };
+
+        strategy.Next.Should().Be(next);
+    }
+
+    [Fact]
+    public void Next_ChangeToNull_Throws()
+    {
+        var strategy = new TestResilienceStrategy();
+
+        strategy.Invoking(s => s.Next = null!).Should().Throw<ArgumentNullException>();
+    }
+
+    [Fact]
+    public void Next_ChangeAfterExecuted_Throws()
+    {
+        var strategy = new TestResilienceStrategy();
+
+        strategy.Execute(_ => { }, default);
+
+        strategy
+            .Invoking(s => s.Next = NullResilienceStrategy.Instance)
+            .Should()
+            .Throw<InvalidOperationException>()
+            .WithMessage("The delegating resilience strategy has already been executed and changing the value of 'Next' property is not allowed.");
+    }
+
+    [Fact]
+    public void Execute_HasNext_EnsureExecuteOrder()
+    {
+        List<int> executions = new();
+
+        var strategy = new TestResilienceStrategy
+        {
+            Before = (_, _) => executions.Add(1),
+            After = (_, _) => executions.Add(5),
+        };
+
+        var next = new TestResilienceStrategy
+        {
+            Before = (_, _) => executions.Add(2),
+            After = (_, _) => executions.Add(4),
+        };
+
+        strategy.Next = next;
+        strategy.Execute(_ => executions.Add(3), default);
+
+        executions.Should().BeInAscendingOrder();
+        executions.Should().HaveCount(5);
+    }
+}

src/Polly.Core.Tests/DummyTest.cs

@@ -0,0 +1,22 @@
+using FluentAssertions;
+using Xunit;
+
+namespace Polly.Core.Tests;
+
+public class NullResilienceStrategyTests
+{
+    [Fact]
+    public void Instance_ShouldNotBeNull()
+    {
+        NullResilienceStrategy.Instance.Should().NotBeNull();
+    }
+
+    [Fact]
+    public void Execute_Ok()
+    {
+        bool executed = false;
+        NullResilienceStrategy.Instance.Execute(_ => executed = true);
+
+        executed.Should().BeTrue();
+    }
+}

src/Polly.Core.Tests/NullResilienceStrategyTests.cs

@@ -7,6 +7,7 @@
     <Nullable>enable</Nullable>
     <SkipPollyUsings>true</SkipPollyUsings>
     <Threshold>100</Threshold>
+    <NoWarn>$(NoWarn);SA1600</NoWarn>
   </PropertyGroup>
 
   <ItemGroup>

src/Polly.Core.Tests/Polly.Core.Tests.csproj

@@ -0,0 +1,81 @@
+using FluentAssertions;
+using Xunit;
+
+namespace Polly.Core.Tests;
+
+public class ResilienceContextTests
+{
+    [Fact]
+    public void Get_EnsureNotNull()
+    {
+        ResilienceContext.Get().Should().NotBeNull();
+    }
+
+    [Fact]
+    public void Get_EnsureDefaults()
+    {
+        var context = ResilienceContext.Get();
+
+        AssertDefaults(context);
+    }
+
+    [Fact]
+    public void Return_Null_Throws()
+    {
+        Assert.Throws<ArgumentNullException>(() => ResilienceContext.Return(null!));
+    }
+
+    [Fact]
+    public void Return_EnsureDefaults()
+    {
+        using var cts = new CancellationTokenSource();
+        var context = ResilienceContext.Get();
+        context.CancellationToken = cts.Token;
+        context.Initialize<bool>(true);
+        context.CancellationToken.Should().Be(cts.Token);
+
+        ResilienceContext.Return(context);
+
+        AssertDefaults(context);
+    }
+
+    [InlineData(true)]
+    [InlineData(false)]
+    [Theory]
+    public void Initialize_Typed_Ok(bool synchronous)
+    {
+        var context = ResilienceContext.Get();
+        context.Initialize<bool>(synchronous);
+
+        context.ResultType.Should().Be(typeof(bool));
+        context.IsVoid.Should().BeFalse();
+        context.IsInitialized.Should().BeTrue();
+        context.IsSynchronous.Should().Be(synchronous);
+        context.ContinueOnCapturedContext.Should().BeFalse();
+    }
+
+    [InlineData(true)]
+    [InlineData(false)]
+    [Theory]
+    public void Initialize_Void_Ok(bool synchronous)
+    {
+        var context = ResilienceContext.Get();
+        context.Initialize<VoidResult>(synchronous);
+
+        context.ResultType.Should().Be(typeof(VoidResult));
+        context.IsVoid.Should().BeTrue();
+        context.IsInitialized.Should().BeTrue();
+        context.IsSynchronous.Should().Be(synchronous);
+        context.ContinueOnCapturedContext.Should().BeFalse();
+    }
+
+    private static void AssertDefaults(ResilienceContext context)
+    {
+        context.IsInitialized.Should().BeFalse();
+        context.ContinueOnCapturedContext.Should().BeFalse();
+        context.IsVoid.Should().BeFalse();
+        context.ResultType.Name.Should().Be("UnknownResult");
+        context.IsSynchronous.Should().BeFalse();
+        context.CancellationToken.Should().Be(CancellationToken.None);
+    }
+}

src/Polly.Core.Tests/ResilienceContextTests.cs

@@ -0,0 +1,77 @@
+using FluentAssertions;
+using Polly.Core.Tests.Utils;
+using Xunit;
+
+namespace Polly.Core.Tests;
+
+#pragma warning disable CS1998 // Async method lacks 'await' operators and will run synchronously
+
+public partial class ResilienceStrategyExtensionsTests
+{
+    public static IEnumerable<object[]> ExecuteAsTaskAsync_EnsureCorrectBehavior_Data()
+    {
+        return ConvertExecuteParameters(ExecuteAsTaskAsync_EnsureCorrectBehavior_ExecuteParameters);
+    }
+
+    private static IEnumerable<ExecuteParameters> ExecuteAsTaskAsync_EnsureCorrectBehavior_ExecuteParameters()
+    {
+        yield return new ExecuteParameters(r => r.ExecuteAsTaskAsync(async _ => { }))
+        {
+            Caption = "ExecuteAsTaskAsync_NoCancellation",
+            AssertContext = AssertResilienceContext,
+            AssertContextAfter = AssertContextNotInitialized,
+        };
+
+        yield return new ExecuteParameters(r => r.ExecuteAsTaskAsync(async t => { t.Should().Be(CancellationToken); }, CancellationToken))
+        {
+            Caption = "ExecuteAsTaskAsync_Cancellation",
+            AssertContext = AssertResilienceContextAndToken,
+            AssertContextAfter = AssertContextNotInitialized,
+        };
+
+        yield return new ExecuteParameters(r => r.ExecuteAsTaskAsync(async (_, s) => { s.Should().Be("dummy-state"); }, ResilienceContext.Get(), "dummy-state"))
+        {
+            Caption = "ExecuteAsTaskAsync_ResilienceContextAndState",
+            AssertContext = AssertResilienceContext,
+            AssertContextAfter = AssertContextInitialized,
+        };
+
+        static void AssertResilienceContext(ResilienceContext context)
+        {
+            context.IsSynchronous.Should().BeFalse();
+            context.IsVoid.Should().BeTrue();
+            context.ContinueOnCapturedContext.Should().BeFalse();
+        }
+
+        static void AssertResilienceContextAndToken(ResilienceContext context)
+        {
+            AssertResilienceContext(context);
+            context.CancellationToken.Should().Be(CancellationToken);
+        }
+
+        static void AssertContextNotInitialized(ResilienceContext context) => context.IsInitialized.Should().BeFalse();
+
+        static void AssertContextInitialized(ResilienceContext context) => context.IsInitialized.Should().BeTrue();
+    }
+
+    [MemberData(nameof(ExecuteAsTaskAsync_EnsureCorrectBehavior_Data))]
+    [Theory]
+    public async Task ExecuteAsTaskAsync_Ok(ExecuteParameters parameters)
+    {
+        ResilienceContext? context = null;
+
+        var strategy = new TestResilienceStrategy
+        {
+            Before = (c, _) =>
+            {
+                context = c;
+                parameters.AssertContext(c);
+            },
+        };
+
+        var result = await parameters.Execute(strategy);
+
+        parameters.AssertContextAfter(context!);
+        parameters.AssertResult(result);
+    }
+}

src/Polly.Core.Tests/ResilienceStrategyExtensionsTests.Async.Task.cs

@@ -0,0 +1,80 @@
+using FluentAssertions;
+using Polly.Core.Tests.Utils;
+using Xunit;
+
+namespace Polly.Core.Tests;
+
+#pragma warning disable CS1998 // Async method lacks 'await' operators and will run synchronously
+
+public partial class ResilienceStrategyExtensionsTests
+{
+    public static IEnumerable<object[]> ExecuteAsTaskAsyncT_EnsureCorrectBehavior_Data()
+    {
+        return ConvertExecuteParameters(ExecuteAsTaskAsyncT_EnsureCorrectBehavior_ExecuteParameters);
+    }
+
+    private static IEnumerable<ExecuteParameters> ExecuteAsTaskAsyncT_EnsureCorrectBehavior_ExecuteParameters()
+    {
+        long result = 12345;
+
+        yield return new ExecuteParameters<long>(r => r.ExecuteAsTaskAsync(async t => result), result)
+        {
+            Caption = "ExecuteAsTaskAsyncT_NoCancellation",
+            AssertContext = AssertResilienceContext,
+            AssertContextAfter = AssertContextNotInitialized,
+        };
+
+        yield return new ExecuteParameters<long>(r => r.ExecuteAsTaskAsync(async t => { t.Should().Be(CancellationToken); return result; }, CancellationToken), result)
+        {
+            Caption = "ExecuteAsTaskAsyncT_Cancellation",
+            AssertContext = AssertResilienceContextAndToken,
+            AssertContextAfter = AssertContextNotInitialized,
+        };
+
+        yield return new ExecuteParameters<long>(r => r.ExecuteAsTaskAsync(async (_, s) => { s.Should().Be("dummy-state"); return result; }, ResilienceContext.Get(), "dummy-state"), result)
+        {
+            Caption = "ExecuteAsTaskAsyncT_ResilienceContextAndState",
+            AssertContext = AssertResilienceContext,
+            AssertContextAfter = AssertContextInitialized,
+        };
+
+        static void AssertResilienceContext(ResilienceContext context)
+        {
+            context.IsSynchronous.Should().BeFalse();
+            context.IsVoid.Should().BeFalse();
+            context.ResultType.Should().Be(typeof(long));
+            context.ContinueOnCapturedContext.Should().BeFalse();
+        }
+
+        static void AssertResilienceContextAndToken(ResilienceContext context)
+        {
+            AssertResilienceContext(context);
+            context.CancellationToken.Should().Be(CancellationToken);
+        }
+
+        static void AssertContextNotInitialized(ResilienceContext context) => context.IsInitialized.Should().BeFalse();
+
+        static void AssertContextInitialized(ResilienceContext context) => context.IsInitialized.Should().BeTrue();
+    }
+
+    [MemberData(nameof(ExecuteAsTaskAsyncT_EnsureCorrectBehavior_Data))]
+    [Theory]
+    public async Task ExecuteAsTaskAsyncT_Ok(ExecuteParameters parameters)
+    {
+        ResilienceContext? context = null;
+
+        var strategy = new TestResilienceStrategy
+        {
+            Before = (c, _) =>
+            {
+                context = c;
+                parameters.AssertContext(c);
+            },
+        };
+
+        var result = await parameters.Execute(strategy);
+
+        parameters.AssertContextAfter(context!);
+        parameters.AssertResult(result);
+    }
+}