ResilienceStrategyRegistry API improvements (#1388)

Author: martintmk

src/Polly.Core/Registry/ResilienceStrategyRegistry.TResult.cs

@@ -41,25 +41,29 @@ public bool TryGet(TKey key, [NotNullWhen(true)] out ResilienceStrategy<TResult>
 
             if (_builders.TryGetValue(key, out var configure))
             {
-                var context = new ConfigureBuilderContext<TKey>(key, _builderNameFormatter(key), _strategyKeyFormatter(key));
-
-#if NETCOREAPP3_0_OR_GREATER
-                strategy = _strategies.GetOrAdd(key, static (_, factory) =>
-                {
-                    return new ResilienceStrategy<TResult>(CreateStrategy(factory.instance._activator, factory.context, factory.configure));
-                },
-                (instance: this, context, configure));
-#else
-                strategy = _strategies.GetOrAdd(key, _ => new ResilienceStrategy<TResult>(CreateStrategy(_activator, context, configure)));
-#endif
-
+                strategy = GetOrAdd(key, configure);
                 return true;
             }
 
             strategy = null;
             return false;
         }
 
+        public ResilienceStrategy<TResult> GetOrAdd(TKey key, Action<ResilienceStrategyBuilder<TResult>, ConfigureBuilderContext<TKey>> configure)
+        {
+            var context = new ConfigureBuilderContext<TKey>(key, _builderNameFormatter(key), _strategyKeyFormatter(key));
+
+#if NETCOREAPP3_0_OR_GREATER
+            return _strategies.GetOrAdd(key, static (_, factory) =>
+            {
+                return new ResilienceStrategy<TResult>(CreateStrategy(factory.instance._activator, factory.context, factory.configure));
+            },
+            (instance: this, context, configure));
+#else
+            return _strategies.GetOrAdd(key, _ => new ResilienceStrategy<TResult>(CreateStrategy(_activator, context, configure)));
+#endif
+        }
+
         public bool TryAddBuilder(TKey key, Action<ResilienceStrategyBuilder<TResult>, ConfigureBuilderContext<TKey>> configure) => _builders.TryAdd(key, configure);
 
         public bool RemoveBuilder(TKey key) => _builders.TryRemove(key, out _);

src/Polly.Core/Registry/ResilienceStrategyRegistry.cs

@@ -118,24 +118,83 @@ public override bool TryGetStrategy(TKey key, [NotNullWhen(true)] out Resilience
 
         if (_builders.TryGetValue(key, out var configure))
         {
-            var context = new ConfigureBuilderContext<TKey>(key, _builderNameFormatter(key), _strategyKeyFormatter(key));
-
-#if NETCOREAPP3_0_OR_GREATER
-            strategy = _strategies.GetOrAdd(key, static (_, factory) =>
-            {
-                return CreateStrategy(factory.instance._activator, factory.context, factory.configure);
-            },
-            (instance: this, context, configure));
-#else
-            strategy = _strategies.GetOrAdd(key, _ => CreateStrategy(_activator, context, configure));
-#endif
+            strategy = GetOrAddStrategy(key, configure);
             return true;
         }
 
         strategy = null;
         return false;
     }
 
+    /// <summary>
+    /// Gets existing strategy or creates a new one using the <paramref name="configure"/> callback.
+    /// </summary>
+    /// <param name="key">The key used to identify the resilience strategy.</param>
+    /// <param name="configure">The callback that configures the strategy builder.</param>
+    /// <returns>An instance of strategy.</returns>
+    public ResilienceStrategy GetOrAddStrategy(TKey key, Action<ResilienceStrategyBuilder> configure)
+    {
+        Guard.NotNull(configure);
+
+        return GetOrAddStrategy(key, (builder, _) => configure(builder));
+    }
+
+    /// <summary>
+    /// Gets existing strategy or creates a new one using the <paramref name="configure"/> callback.
+    /// </summary>
+    /// <param name="key">The key used to identify the resilience strategy.</param>
+    /// <param name="configure">The callback that configures the strategy builder.</param>
+    /// <returns>An instance of strategy.</returns>
+    public ResilienceStrategy GetOrAddStrategy(TKey key, Action<ResilienceStrategyBuilder, ConfigureBuilderContext<TKey>> configure)
+    {
+        Guard.NotNull(configure);
+
+        if (_strategies.TryGetValue(key, out var strategy))
+        {
+            return strategy;
+        }
+
+        var context = new ConfigureBuilderContext<TKey>(key, _builderNameFormatter(key), _strategyKeyFormatter(key));
+
+#if NETCOREAPP3_0_OR_GREATER
+        return _strategies.GetOrAdd(key, static (_, factory) =>
+        {
+            return CreateStrategy(factory.instance._activator, factory.context, factory.configure);
+        },
+        (instance: this, context, configure));
+#else
+        return _strategies.GetOrAdd(key, _ => CreateStrategy(_activator, context, configure));
+#endif
+    }
+
+    /// <summary>
+    /// Gets existing strategy or creates a new one using the <paramref name="configure"/> callback.
+    /// </summary>
+    /// <typeparam name="TResult">The type of result that the resilience strategy handles.</typeparam>
+    /// <param name="key">The key used to identify the resilience strategy.</param>
+    /// <param name="configure">The callback that configures the strategy builder.</param>
+    /// <returns>An instance of strategy.</returns>
+    public ResilienceStrategy<TResult> GetOrAddStrategy<TResult>(TKey key, Action<ResilienceStrategyBuilder<TResult>> configure)
+    {
+        Guard.NotNull(configure);
+
+        return GetOrAddStrategy<TResult>(key, (builder, _) => configure(builder));
+    }
+
+    /// <summary>
+    /// Gets existing strategy or creates a new one using the <paramref name="configure"/> callback.
+    /// </summary>
+    /// <typeparam name="TResult">The type of result that the resilience strategy handles.</typeparam>
+    /// <param name="key">The key used to identify the resilience strategy.</param>
+    /// <param name="configure">The callback that configures the strategy builder.</param>
+    /// <returns>An instance of strategy.</returns>
+    public ResilienceStrategy<TResult> GetOrAddStrategy<TResult>(TKey key, Action<ResilienceStrategyBuilder<TResult>, ConfigureBuilderContext<TKey>> configure)
+    {
+        Guard.NotNull(configure);
+
+        return GetGenericRegistry<TResult>().GetOrAdd(key, configure);
+    }
+
     /// <summary>
     /// Tries to add a resilience strategy builder to the registry.
     /// </summary>

src/Polly.Extensions/DependencyInjection/AddResilienceStrategyContext.cs

@@ -1,7 +1,7 @@
 using System;
 using Microsoft.Extensions.DependencyInjection;
 using Microsoft.Extensions.Options;
-using Polly.Extensions.Utils;
+using Polly.Extensions.Registry;
 using Polly.Registry;
 
 namespace Polly.Extensions.DependencyInjection;
@@ -53,12 +53,7 @@ internal AddResilienceStrategyContext(ConfigureBuilderContext<TKey> registryCont
     /// You can listen for changes only for single options. If you call this method multiple times, the preceding calls are ignored and only the last one wins.
     /// </para>
     /// </remarks>
-    public void EnableReloads<TOptions>(string? name = null)
-    {
-        var monitor = ServiceProvider.GetRequiredService<IOptionsMonitor<TOptions>>();
-
-        RegistryContext.EnableReloads(() => new OptionsReloadHelper<TOptions>(monitor, name ?? Options.DefaultName).GetCancellationToken);
-    }
+    public void EnableReloads<TOptions>(string? name = null) => RegistryContext.EnableReloads(ServiceProvider.GetRequiredService<IOptionsMonitor<TOptions>>(), name);
 
     /// <summary>
     /// Gets the options identified by <paramref name="name"/>.

src/Polly.Extensions/DependencyInjection/PollyServiceCollectionExtensions.cs

@@ -25,13 +25,13 @@ public static class PollyServiceCollectionExtensions
     /// <param name="configure">An action that configures the resilience strategy.</param>
     /// <returns>The updated <see cref="IServiceCollection"/> with the registered resilience strategy.</returns>
     /// <exception cref="InvalidOperationException">Thrown if the resilience strategy builder with the provided key has already been added to the registry.</exception>
+    /// <exception cref="ArgumentNullException">Thrown when <paramref name="services"/> or <paramref name="configure"/> is <see langword="null"/>.</exception>
     /// <remarks>
     /// You can retrieve the registered strategy by resolving the <see cref="ResilienceStrategyProvider{TKey}"/> class from the dependency injection container.
     /// <para>
     /// This call enables the telemetry for the registered resilience strategy.
     /// </para>
     /// </remarks>
-    /// <exception cref="ArgumentNullException">Thrown when <paramref name="services"/> or <paramref name="configure"/> is <see langword="null"/>.</exception>
     public static IServiceCollection AddResilienceStrategy<TKey, TResult>(
         this IServiceCollection services,
         TKey key,
@@ -54,13 +54,13 @@ public static IServiceCollection AddResilienceStrategy<TKey, TResult>(
     /// <param name="configure">An action that configures the resilience strategy.</param>
     /// <returns>The updated <see cref="IServiceCollection"/> with the registered resilience strategy.</returns>
     /// <exception cref="InvalidOperationException">Thrown if the resilience strategy builder with the provided key has already been added to the registry.</exception>
+    /// <exception cref="ArgumentNullException">Thrown when <paramref name="services"/> or <paramref name="configure"/> is <see langword="null"/>.</exception>
     /// <remarks>
     /// You can retrieve the registered strategy by resolving the <see cref="ResilienceStrategyProvider{TKey}"/> class from the dependency injection container.
     /// <para>
     /// This call enables the telemetry for the registered resilience strategy.
     /// </para>
     /// </remarks>
-    /// <exception cref="ArgumentNullException">Thrown when <paramref name="services"/> or <paramref name="configure"/> is <see langword="null"/>.</exception>
     public static IServiceCollection AddResilienceStrategy<TKey, TResult>(
         this IServiceCollection services,
         TKey key,
@@ -85,7 +85,7 @@ public static IServiceCollection AddResilienceStrategy<TKey, TResult>(
                 });
             });
 
-        return AddResilienceStrategyRegistry<TKey>(services);
+        return AddResilienceStrategy<TKey>(services);
     }
 
     /// <summary>
@@ -97,13 +97,13 @@ public static IServiceCollection AddResilienceStrategy<TKey, TResult>(
     /// <param name="configure">An action that configures the resilience strategy.</param>
     /// <returns>The updated <see cref="IServiceCollection"/> with the registered resilience strategy.</returns>
     /// <exception cref="InvalidOperationException">Thrown if the resilience strategy builder with the provided key has already been added to the registry.</exception>
+    /// <exception cref="ArgumentNullException">Thrown when <paramref name="services"/> or <paramref name="configure"/> is <see langword="null"/>.</exception>
     /// <remarks>
     /// You can retrieve the registered strategy by resolving the <see cref="ResilienceStrategyProvider{TKey}"/> class from the dependency injection container.
     /// <para>
     /// This call enables the telemetry for the registered resilience strategy.
     /// </para>
     /// </remarks>
-    /// <exception cref="ArgumentNullException">Thrown when <paramref name="services"/> or <paramref name="configure"/> is <see langword="null"/>.</exception>
     public static IServiceCollection AddResilienceStrategy<TKey>(
         this IServiceCollection services,
         TKey key,
@@ -125,13 +125,13 @@ public static IServiceCollection AddResilienceStrategy<TKey>(
     /// <param name="configure">An action that configures the resilience strategy.</param>
     /// <returns>The updated <see cref="IServiceCollection"/> with the registered resilience strategy.</returns>
     /// <exception cref="InvalidOperationException">Thrown if the resilience strategy builder with the provided key has already been added to the registry.</exception>
+    /// <exception cref="ArgumentNullException">Thrown when <paramref name="services"/> or <paramref name="configure"/> is <see langword="null"/>.</exception>
     /// <remarks>
     /// You can retrieve the registered strategy by resolving the <see cref="ResilienceStrategyProvider{TKey}"/> class from the dependency injection container.
     /// <para>
     /// This call enables the telemetry for the registered resilience strategy.
     /// </para>
     /// </remarks>
-    /// <exception cref="ArgumentNullException">Thrown when <paramref name="services"/> or <paramref name="configure"/> is <see langword="null"/>.</exception>
     public static IServiceCollection AddResilienceStrategy<TKey>(
         this IServiceCollection services,
         TKey key,
@@ -156,12 +156,28 @@ public static IServiceCollection AddResilienceStrategy<TKey>(
                 });
             });
 
-        return AddResilienceStrategyRegistry<TKey>(services);
+        return AddResilienceStrategy<TKey>(services);
     }
 
-    private static IServiceCollection AddResilienceStrategyRegistry<TKey>(this IServiceCollection services)
+    /// <summary>
+    /// Adds the infrastructure that allows configuring and retrieving resilience strategies using the <typeparamref name="TKey"/> key.
+    /// </summary>
+    /// <typeparam name="TKey">The type of the key used to identify the resilience strategy.</typeparam>
+    /// <param name="services">The <see cref="IServiceCollection"/> to add the resilience strategy to.</param>
+    /// <returns>The updated <see cref="IServiceCollection"/> with additional services added.</returns>
+    /// <exception cref="ArgumentNullException">Thrown when <paramref name="services"/> is <see langword="null"/>.</exception>
+    /// <remarks>
+    /// You can retrieve the strategy registry by resolving the <see cref="ResilienceStrategyProvider{TKey}"/>
+    /// or <see cref="ResilienceStrategyRegistry{TKey}"/> class from the dependency injection container.
+    /// <para>
+    /// This call enables telemetry for all resilience strategies created using <see cref="ResilienceStrategyRegistry{TKey}"/>.
+    /// </para>
+    /// </remarks>
+    public static IServiceCollection AddResilienceStrategy<TKey>(this IServiceCollection services)
         where TKey : notnull
     {
+        Guard.NotNull(services);
+
         // check marker to ensure the APIs bellow are called only once for each TKey type
         // this prevents polluting the service collection with unnecessary Configure calls
         if (services.Contains(RegistryMarker<TKey>.ServiceDescriptor))
@@ -172,7 +188,7 @@ private static IServiceCollection AddResilienceStrategyRegistry<TKey>(this IServ
         services.AddOptions();
         services.Add(RegistryMarker<TKey>.ServiceDescriptor);
         services.AddResilienceStrategyBuilder();
-        services.AddResilienceStrategyRegistry<TKey>();
+        services.AddResilienceStrategy<TKey>();
 
         services.TryAddSingleton(serviceProvider =>
         {

src/Polly.Extensions/Polly.Extensions.csproj

@@ -29,6 +29,6 @@
     <PackageReference Include="Microsoft.Extensions.Options" />
     <PackageReference Include="Microsoft.Extensions.Logging.Abstractions" />
     <PackageReference Include="System.Diagnostics.DiagnosticSource" />
-    <Reference Include="System.Net.Http" Condition="'$(TargetFrameworkIdentifier)' == '.NETFramework'"/>
+    <Reference Include="System.Net.Http" Condition="'$(TargetFrameworkIdentifier)' == '.NETFramework'" />
   </ItemGroup>
 </Project>

src/Polly.Extensions/Registry/ConfigureBuilderContextExtensions.cs

@@ -0,0 +1,36 @@
+using Microsoft.Extensions.Options;
+using Polly.Extensions.Utils;
+using Polly.Registry;
+using Polly.Utils;
+
+namespace Polly.Extensions.Registry;
+
+/// <summary>
+/// Extensions for <see cref="ConfigureBuilderContext{TKey}"/>.
+/// </summary>
+public static class ConfigureBuilderContextExtensions
+{
+    /// <summary>
+    /// Enables dynamic reloading of the resilience strategy whenever the <typeparamref name="TOptions"/> options are changed.
+    /// </summary>
+    /// <typeparam name="TKey">The type of the key used to identify the resilience strategy.</typeparam>
+    /// <typeparam name="TOptions">The options type to listen to.</typeparam>
+    /// <param name="context">The builder context.</param>
+    /// <param name="optionsMonitor">The options monitor.</param>
+    /// <param name="name">The named options, if any.</param>
+    /// <remarks>
+    /// You can decide based on the <paramref name="name"/> to listen for changes in global options or named options.
+    /// If <paramref name="name"/> is <see langword="null"/> then the global options are listened to.
+    /// <para>
+    /// You can listen for changes only for single options. If you call this method multiple times, the preceding calls are ignored and only the last one wins.
+    /// </para>
+    /// </remarks>
+    public static void EnableReloads<TKey, TOptions>(this ConfigureBuilderContext<TKey> context, IOptionsMonitor<TOptions> optionsMonitor, string? name = null)
+        where TKey : notnull
+    {
+        Guard.NotNull(context);
+        Guard.NotNull(optionsMonitor);
+
+        context.EnableReloads(() => new OptionsReloadHelper<TOptions>(optionsMonitor, name ?? Options.DefaultName).GetCancellationToken);
+    }
+}

test/Polly.Core.Tests/Registry/ResilienceStrategyRegistryTests.cs

@@ -3,6 +3,7 @@
 using Polly.Registry;
 using Polly.Retry;
 using Polly.Telemetry;
+using Polly.Timeout;
 
 namespace Polly.Core.Tests.Registry;
 
@@ -429,5 +430,34 @@ public void EnableReloads_Generic_Ok()
         tries.Should().Be(retryCount + 1);
     }
 
+    [Fact]
+    public void GetOrAddStrategy_Ok()
+    {
+        var id = new StrategyId(typeof(string), "A");
+        var called = 0;
+
+        var registry = CreateRegistry();
+        var strategy = registry.GetOrAddStrategy(id, builder => { builder.AddTimeout(TimeSpan.FromSeconds(1)); called++; });
+        var otherStrategy = registry.GetOrAddStrategy(id, builder => { builder.AddTimeout(TimeSpan.FromSeconds(1)); called++; });
+
+        strategy.Should().BeOfType<TimeoutResilienceStrategy>();
+        strategy.Should().BeSameAs(otherStrategy);
+        called.Should().Be(1);
+    }
+
+    [Fact]
+    public void GetOrAddStrategy_Generic_Ok()
+    {
+        var id = new StrategyId(typeof(string), "A");
+        var called = 0;
+
+        var registry = CreateRegistry();
+        var strategy = registry.GetOrAddStrategy<string>(id, builder => { builder.AddTimeout(TimeSpan.FromSeconds(1)); called++; });
+        var otherStrategy = registry.GetOrAddStrategy<string>(id, builder => { builder.AddTimeout(TimeSpan.FromSeconds(1)); called++; });
+
+        strategy.Strategy.Should().BeOfType<TimeoutResilienceStrategy>();
+        strategy.Should().BeSameAs(otherStrategy);
+    }
+
     private ResilienceStrategyRegistry<StrategyId> CreateRegistry() => new(_options);
 }

test/Polly.Extensions.Tests/DependencyInjection/PollyServiceCollectionExtensionTests.cs

@@ -254,6 +254,16 @@ public void AddResilienceStrategy_Multiple_Ok()
             .HaveCount(30);
     }
 
+    [Fact]
+    public void AddResilienceStrategyInfra_Ok()
+    {
+        var provider = new ServiceCollection().AddResilienceStrategy<string>().BuildServiceProvider();
+
+        provider.GetRequiredService<ResilienceStrategyRegistry<string>>().Should().NotBeNull();
+        provider.GetRequiredService<ResilienceStrategyProvider<string>>().Should().NotBeNull();
+        provider.GetRequiredService<ResilienceStrategyBuilder>().DiagnosticSource.Should().NotBeNull();
+    }
+
     private void AddResilienceStrategy(string key, Action<ResilienceStrategyBuilderContext>? onBuilding = null)
     {
         _services.AddResilienceStrategy(key, builder =>