Bridge between Polly V7 and Polly V8 (#1255)

src/Polly.Specs/Polly.Specs.csproj

@@ -10,6 +10,7 @@
   </PropertyGroup>
 
   <ItemGroup>
+    <ProjectReference Include="..\Polly.TestUtils\Polly.TestUtils.csproj" />
     <ProjectReference Include="..\Polly\Polly.csproj" />
   </ItemGroup>
 </Project>

src/Polly.Specs/ResilienceStrategyConversionExtensionsTests.cs

@@ -0,0 +1,188 @@
+using Polly.Strategy;
+using Polly.TestUtils;
+
+namespace Polly.Specs;
+
+public class ResilienceStrategyConversionExtensionsTests
+{
+    private static readonly ResiliencePropertyKey<string> Incoming = new ResiliencePropertyKey<string>("incoming-key");
+
+    private static readonly ResiliencePropertyKey<string> Executing = new ResiliencePropertyKey<string>("executing-key");
+
+    private static readonly ResiliencePropertyKey<string> Outgoing = new ResiliencePropertyKey<string>("outgoing-key");
+
+    private readonly TestResilienceStrategy _strategy;
+    private readonly ResilienceStrategy<string> _genericStrategy;
+    private bool _isSynchronous;
+    private bool _isVoid;
+    private Type? _resultType;
+
+    public ResilienceStrategyConversionExtensionsTests()
+    {
+        _strategy = new TestResilienceStrategy();
+        _strategy.Before = (context, ct) =>
+        {
+            context.IsVoid.Should().Be(_isVoid);
+            context.IsSynchronous.Should().Be(_isSynchronous);
+            context.Properties.Set(Outgoing, "outgoing-value");
+            context.Properties.GetValue(Incoming, string.Empty).Should().Be("incoming-value");
+
+            if (_resultType != null)
+            {
+                context.ResultType.Should().Be(_resultType);
+            }
+        };
+
+        _genericStrategy = new ResilienceStrategyBuilder<string>()
+            .AddStrategy(_strategy)
+            .Build();
+    }
+
+    [Fact]
+    public void AsSyncPolicy_Ok()
+    {
+        _isVoid = true;
+        _isSynchronous = true;
+        var context = new Context
+        {
+            [Incoming.Key] = "incoming-value"
+        };
+
+        _strategy.AsSyncPolicy().Execute(c =>
+        {
+            context[Executing.Key] = "executing-value";
+        },
+        context);
+
+        AssertContext(context);
+    }
+
+    [Fact]
+    public void AsSyncPolicy_Generic_Ok()
+    {
+        _isVoid = false;
+        _isSynchronous = true;
+        _resultType = typeof(string);
+        var context = new Context
+        {
+            [Incoming.Key] = "incoming-value"
+        };
+
+        var result = _genericStrategy.AsSyncPolicy().Execute(c => { context[Executing.Key] = "executing-value"; return "dummy"; }, context);
+        AssertContext(context);
+        result.Should().Be("dummy");
+    }
+
+    [Fact]
+    public void AsSyncPolicy_Result_Ok()
+    {
+        _isVoid = false;
+        _isSynchronous = true;
+        _resultType = typeof(string);
+        var context = new Context
+        {
+            [Incoming.Key] = "incoming-value"
+        };
+
+        var result = _strategy.AsSyncPolicy().Execute(c => { context[Executing.Key] = "executing-value"; return "dummy"; }, context);
+
+        AssertContext(context);
+        result.Should().Be("dummy");
+    }
+
+    [Fact]
+    public async Task AsAsyncPolicy_Ok()
+    {
+        _isVoid = true;
+        _isSynchronous = false;
+        var context = new Context
+        {
+            [Incoming.Key] = "incoming-value"
+        };
+
+        await _strategy.AsAsyncPolicy().ExecuteAsync(c =>
+        {
+            context[Executing.Key] = "executing-value";
+            return Task.CompletedTask;
+        },
+        context);
+
+        AssertContext(context);
+    }
+
+    [Fact]
+    public async Task AsAsyncPolicy_Generic_Ok()
+    {
+        _isVoid = false;
+        _isSynchronous = false;
+        _resultType = typeof(string);
+        var context = new Context
+        {
+            [Incoming.Key] = "incoming-value"
+        };
+
+        var result = await _genericStrategy.AsAsyncPolicy().ExecuteAsync(c =>
+        {
+            context[Executing.Key] = "executing-value";
+            return Task.FromResult("dummy");
+        },
+        context);
+        AssertContext(context);
+        result.Should().Be("dummy");
+    }
+
+    [Fact]
+    public async Task AsAsyncPolicy_Result_Ok()
+    {
+        _isVoid = false;
+        _isSynchronous = false;
+        _resultType = typeof(string);
+        var context = new Context
+        {
+            [Incoming.Key] = "incoming-value"
+        };
+
+        var result = await _strategy.AsAsyncPolicy().ExecuteAsync(c =>
+        {
+            context[Executing.Key] = "executing-value";
+            return Task.FromResult("dummy");
+        },
+        context);
+
+        AssertContext(context);
+        result.Should().Be("dummy");
+    }
+
+    [Fact]
+    public void RetryStrategy_AsSyncPolicy_Ok()
+    {
+        var policy = new ResilienceStrategyBuilder<string>()
+            .AddRetry(new RetryStrategyOptions<string>
+            {
+                ShouldRetry = _ => PredicateResult.True,
+                BackoffType = RetryBackoffType.Constant,
+                RetryCount = 5,
+                BaseDelay = TimeSpan.FromMilliseconds(1)
+            })
+            .Build()
+            .AsSyncPolicy();
+
+        var tries = 0;
+        policy.Execute(
+            () =>
+            {
+                tries++;
+                return "dummy";
+            })
+            .Should()
+            .Be("dummy");
+
+        tries.Should().Be(6);
+    }
+
+    private static void AssertContext(Context context)
+    {
+        context[Outgoing.Key].Should().Be("outgoing-value");
+        context[Executing.Key].Should().Be("executing-value");
+    }
+}

src/Polly/Context.cs

@@ -1,4 +1,4 @@
-namespace Polly;
+namespace Polly;
 
 /// <summary>
 /// Context that carries with a single execution through a Policy.   Commonly-used properties are directly on the class.  Backed by a dictionary of string key / object value pairs, to which user-defined values may be added.
@@ -37,7 +37,7 @@ public Context()
     /// <summary>
     /// A key unique to the call site of the current execution.
     /// <remarks>Policy instances are commonly reused across multiple call sites.  Set an OperationKey so that logging and metrics can distinguish usages of policy instances at different call sites.</remarks>
-    /// <remarks>The value is set by using the <see cref="Context(String)"/> constructor taking an operationKey parameter.</remarks>
+    /// <remarks>The value is set by using the <see cref="Context(string)"/> constructor taking an operationKey parameter.</remarks>
     /// </summary>
     public string OperationKey { get; }
 

src/Polly/ResilienceStrategyConversionExtensions.cs

@@ -0,0 +1,46 @@
+using Polly.Utilities.Wrappers;
+using Polly.Utils;
+
+namespace Polly;
+
+/// <summary>
+/// Extensions for conversion of resilience strategies to policies.
+/// </summary>
+public static class ResilienceStrategyConversionExtensions
+{
+    /// <summary>
+    /// Converts a <see cref="ResilienceStrategy"/> to an <see cref="IAsyncPolicy"/>.
+    /// </summary>
+    /// <param name="strategy">The strategy instance.</param>
+    /// <returns>An instance of <see cref="IAsyncPolicy"/>.</returns>
+    /// <exception cref="ArgumentNullException">Thrown when <paramref name="strategy"/> is <see langword="null"/>.</exception>
+    public static IAsyncPolicy AsAsyncPolicy(this ResilienceStrategy strategy)
+        => new ResilienceStrategyAsyncPolicy(strategy ?? throw new ArgumentNullException(nameof(strategy)));
+
+    /// <summary>
+    /// Converts a <see cref="ResilienceStrategy{TResult}"/> to an <see cref="IAsyncPolicy{TResult}"/>.
+    /// </summary>
+    /// <param name="strategy">The strategy instance.</param>
+    /// <returns>An instance of <see cref="IAsyncPolicy{TResult}"/>.</returns>
+    /// <exception cref="ArgumentNullException">Thrown when <paramref name="strategy"/> is <see langword="null"/>.</exception>
+    public static IAsyncPolicy<TResult> AsAsyncPolicy<TResult>(this ResilienceStrategy<TResult> strategy)
+        => new ResilienceStrategyAsyncPolicy<TResult>(strategy ?? throw new ArgumentNullException(nameof(strategy)));
+
+    /// <summary>
+    /// Converts a <see cref="ResilienceStrategy"/> to an <see cref="ISyncPolicy"/>.
+    /// </summary>
+    /// <param name="strategy">The strategy instance.</param>
+    /// <returns>An instance of <see cref="ISyncPolicy"/>.</returns>
+    /// <exception cref="ArgumentNullException">Thrown when <paramref name="strategy"/> is <see langword="null"/>.</exception>
+    public static ISyncPolicy AsSyncPolicy(this ResilienceStrategy strategy)
+        => new ResilienceStrategySyncPolicy(strategy ?? throw new ArgumentNullException(nameof(strategy)));
+
+    /// <summary>
+    /// Converts a <see cref="ResilienceStrategy{TResult}"/> to an <see cref="ISyncPolicy{TResult}"/>.
+    /// </summary>
+    /// <param name="strategy">The strategy instance.</param>
+    /// <returns>An instance of <see cref="ISyncPolicy{TResult}"/>.</returns>
+    /// <exception cref="ArgumentNullException">Thrown when <paramref name="strategy"/> is <see langword="null"/>.</exception>
+    public static ISyncPolicy<TResult> AsSyncPolicy<TResult>(this ResilienceStrategy<TResult> strategy)
+        => new ResilienceStrategySyncPolicy<TResult>(strategy ?? throw new ArgumentNullException(nameof(strategy)));
+}

src/Polly/Utilities/Wrappers/ResilienceContextFactory.cs

@@ -0,0 +1,42 @@
+namespace Polly.Utilities.Wrappers;
+
+internal static class ResilienceContextFactory
+{
+    public static readonly ResiliencePropertyKey<Context> ContextKey = new("Polly.Legacy.Context");
+
+    public static ResilienceContext Create(Context context, CancellationToken cancellationToken, bool continueOnCapturedContext)
+    {
+        var resilienceContext = ResilienceContext.Get();
+        resilienceContext.CancellationToken = cancellationToken;
+        resilienceContext.ContinueOnCapturedContext = continueOnCapturedContext;
+
+        foreach (var pair in context)
+        {
+            var props = (IDictionary<string, object>)resilienceContext.Properties;
+            props.Add(pair.Key, pair.Value);
+        }
+
+        resilienceContext.Properties.Set(ContextKey, context);
+
+        return resilienceContext;
+    }
+
+    public static void Restore(ResilienceContext context)
+    {
+        var originalContext = context.GetContext();
+
+        foreach (var pair in context.Properties)
+        {
+            if (pair.Key == ContextKey.Key)
+            {
+                continue;
+            }
+
+            originalContext[pair.Key] = pair.Value;
+        }
+
+        ResilienceContext.Return(context);
+    }
+
+    public static Context GetContext(this ResilienceContext resilienceContext) => resilienceContext.Properties.GetValue(ContextKey, null!);
+}

src/Polly/Utilities/Wrappers/ResilienceStrategyAsyncPolicy.TResult.cs

@@ -0,0 +1,28 @@
+namespace Polly.Utilities.Wrappers;
+
+internal sealed class ResilienceStrategyAsyncPolicy<TResult> : AsyncPolicy<TResult>
+{
+    private readonly ResilienceStrategy<TResult> _strategy;
+
+    public ResilienceStrategyAsyncPolicy(ResilienceStrategy<TResult> strategy) => _strategy = strategy;
+
+    protected sealed override async Task<TResult> ImplementationAsync(Func<Context, CancellationToken, Task<TResult>> action, Context context, CancellationToken cancellationToken, bool continueOnCapturedContext)
+    {
+        var resilienceContext = ResilienceContextFactory.Create(context, cancellationToken, continueOnCapturedContext);
+
+        try
+        {
+            return await _strategy.ExecuteAsync(
+                static async (context, state) =>
+                {
+                    return await state(context.GetContext(), context.CancellationToken).ConfigureAwait(context.ContinueOnCapturedContext);
+                },
+                resilienceContext,
+                action).ConfigureAwait(continueOnCapturedContext);
+        }
+        finally
+        {
+            ResilienceContextFactory.Restore(resilienceContext);
+        }
+    }
+}

src/Polly/Utilities/Wrappers/ResilienceStrategyAsyncPolicy.cs

@@ -0,0 +1,56 @@
+namespace Polly.Utilities.Wrappers;
+
+internal sealed class ResilienceStrategyAsyncPolicy : AsyncPolicy
+{
+    private readonly ResilienceStrategy _strategy;
+
+    public ResilienceStrategyAsyncPolicy(ResilienceStrategy strategy) => _strategy = strategy;
+
+    protected sealed override async Task ImplementationAsync(
+        Func<Context, CancellationToken, Task> action,
+        Context context,
+        CancellationToken cancellationToken,
+        bool continueOnCapturedContext)
+    {
+        var resilienceContext = ResilienceContextFactory.Create(context, cancellationToken, continueOnCapturedContext);
+
+        try
+        {
+            await _strategy.ExecuteAsync(
+                static async (context, state) =>
+                {
+                    await state(context.GetContext(), context.CancellationToken).ConfigureAwait(context.ContinueOnCapturedContext);
+                },
+                resilienceContext,
+                action).ConfigureAwait(continueOnCapturedContext);
+        }
+        finally
+        {
+            ResilienceContextFactory.Restore(resilienceContext);
+        }
+    }
+
+    protected override async Task<TResult> ImplementationAsync<TResult>(
+        Func<Context, CancellationToken, Task<TResult>> action,
+        Context context,
+        CancellationToken cancellationToken,
+        bool continueOnCapturedContext)
+    {
+        var resilienceContext = ResilienceContextFactory.Create(context, cancellationToken, continueOnCapturedContext);
+
+        try
+        {
+            return await _strategy.ExecuteAsync(
+                static async (context, state) =>
+                {
+                    return await state(context.GetContext(), context.CancellationToken).ConfigureAwait(context.ContinueOnCapturedContext);
+                },
+                resilienceContext,
+                action).ConfigureAwait(continueOnCapturedContext);
+        }
+        finally
+        {
+            ResilienceContextFactory.Restore(resilienceContext);
+        }
+    }
+}