More dependency injection improvements

README.md

@@ -265,7 +265,7 @@ It will be retrieved from the service provider every time a cache refresh is req
 Create and configure your `CacheStack`, this is the backbone for Cache Tower.
 
 ```csharp
-services.AddCacheStack<UserContext>(builder => builder
+services.AddCacheStack<UserContext>((provider, builder) => builder
 	.AddMemoryCacheLayer()
 	.AddRedisCacheLayer(/* Your Redis Connection */, new RedisCacheLayerOptions(ProtobufCacheSerializer.Instance))
 	.WithCleanupFrequency(TimeSpan.FromMinutes(5))
@@ -353,7 +353,7 @@ await cacheStack.GetOrSetAsync<MyCachedType>("my-cache-key", async (oldValue, co
 The type of `context` is established at the time of configuring the cache stack.
 
 ```csharp
-services.AddCacheStack<MyContext>(builder => builder
+services.AddCacheStack<MyContext>((provider, builder) => builder
 	.AddMemoryCacheLayer()
 	.WithCleanupFrequency(TimeSpan.FromMinutes(5))
 );
@@ -366,7 +366,31 @@ You can use this context to hold any of the other objects or properties you need
 
 |ℹ Need a custom context resolving solution? |
 |:-|
-|You can specify your own context activator via `AddCacheStack` by implementing a custom `ICacheContextActivator`. To see a complete example, see [this integration for SimpleInjector](https://github.com/mgoodfellow/CacheTower.ContextActivators.SimpleInjector)|
+|You can specify your own context activator via `builder.CacheContextActivator` by implementing a custom `ICacheContextActivator`. To see a complete example, see [this integration for SimpleInjector](https://github.com/mgoodfellow/CacheTower.ContextActivators.SimpleInjector)|
+
+## <a id="named-cache-stacks"> 🏷 Named Cache Stacks
+
+You might not always want a single large `CacheStack` shared between all your code - perhaps you want an in-memory cache with a Redis layer for one section and a file cache for another.
+Cache Tower supports named `CacheStack` implementations via `ICacheStackAccessor`/`ICacheStackAccessor<MyContext>`.
+
+This follows a similar pattern to how `IHttpClientFactory` works, allowing you to fetch the specific `CacheStack` implementation you want within your own class.
+
+```csharp
+services.AddCacheStack<MyContext>("MyAwesomeCacheStack", (provider, builder) => builder
+	.AddMemoryCacheLayer()
+	.WithCleanupFrequency(TimeSpan.FromMinutes(5))
+);
+
+public class MyController
+{
+	private readonly ICacheStack<MyContext> cacheStack;
+
+	public MyController(ICacheStackAccessor<MyContext> cacheStackAccessor)
+	{
+		cacheStack = cacheStackAccessor.GetCacheStack("MyAwesomeCacheStack");
+	}
+}
+```
 
 ## <a id="extensions" /> 🏗 Cache Tower Extensions
 

src/CacheTower/ICacheStackAccessor.cs

@@ -0,0 +1,91 @@
+using System;
+using System.Collections.Concurrent;
+using System.Collections.Generic;
+using System.Linq;
+
+namespace CacheTower;
+
+/// <summary>
+/// Provides access to a named implementation of <see cref="ICacheStack"/>.
+/// </summary>
+public interface ICacheStackAccessor
+{
+	/// <summary>
+	/// Creates or returns existing named <see cref="ICacheStack"/> base on the configured builder.
+	/// </summary>
+	/// <param name="name">The name of the <see cref="ICacheStack"/> that has been configured.</param>
+	/// <returns></returns>
+	ICacheStack GetCacheStack(string name);
+}
+
+/// <summary>
+/// Provides access to a named implementation of <see cref="ICacheStack{TContext}"/>.
+/// </summary>
+/// <typeparam name="TContext">The type of context that is passed during the cache entry generation process.</typeparam>
+public interface ICacheStackAccessor<TContext>
+{
+	/// <summary>
+	/// Creates or returns existing named <see cref="ICacheStack{TContext}"/> base on the configured builder.
+	/// </summary>
+	/// <param name="name">The name of the <see cref="ICacheStack{TContext}"/> that has been configured.</param>
+	/// <returns></returns>
+	ICacheStack<TContext> GetCacheStack(string name);
+}
+
+internal record NamedCacheStackProvider(string Name, Func<IServiceProvider, ICacheStack> Provider);
+internal class NamedCacheStackLookup
+{
+	private readonly ConcurrentDictionary<string, Lazy<ICacheStack>> cachedDependencies = new(StringComparer.Ordinal);
+	private readonly Dictionary<string, NamedCacheStackProvider> namedProviders;
+	private readonly IServiceProvider serviceProvider;
+
+	public NamedCacheStackLookup(
+		IServiceProvider serviceProvider,
+		IEnumerable<NamedCacheStackProvider> namedProviders
+	)
+	{
+		this.serviceProvider = serviceProvider;
+		this.namedProviders = namedProviders.ToDictionary(p => p.Name);
+	}
+
+	public ICacheStack GetCacheStack(string name)
+	{
+		if (!namedProviders.TryGetValue(name, out var dependencyProvider))
+		{
+			throw new ArgumentException($"No ICacheStack is registered with the name \"{name}\"");
+		}
+
+		return cachedDependencies.GetOrAdd(name, name => new Lazy<ICacheStack>(() => dependencyProvider.Provider(serviceProvider))).Value;
+	}
+}
+
+internal class CacheStackAccessor : ICacheStackAccessor
+{
+	private readonly NamedCacheStackLookup cacheStackAccessor;
+
+	public CacheStackAccessor(NamedCacheStackLookup cacheStackAccessor)
+	{
+		this.cacheStackAccessor = cacheStackAccessor;
+	}
+
+	public ICacheStack GetCacheStack(string name) => cacheStackAccessor.GetCacheStack(name);
+}
+
+internal class CacheStackAccessor<TContext> : ICacheStackAccessor<TContext>
+{
+	private readonly NamedCacheStackLookup cacheStackAccessor;
+
+	public CacheStackAccessor(NamedCacheStackLookup cacheStackAccessor)
+	{
+		this.cacheStackAccessor = cacheStackAccessor;
+	}
+
+	public ICacheStack<TContext> GetCacheStack(string name)
+	{
+		if (cacheStackAccessor.GetCacheStack(name) is not ICacheStack<TContext> cacheStack)
+		{
+			throw new InvalidOperationException($"Registered ICacheStack for \"{name}\" is not compatible with {typeof(ICacheStack<TContext>)}");
+		}
+		return cacheStack;
+	}
+}

src/CacheTower/ServiceCollectionExtensions.cs

@@ -1,10 +1,12 @@
 using System;
 using System.Collections.Generic;
+using System.ComponentModel;
 using System.Linq;
 using CacheTower;
 using CacheTower.Extensions;
 using CacheTower.Providers.FileSystem;
 using CacheTower.Providers.Memory;
+using Microsoft.Extensions.DependencyInjection.Extensions;
 
 namespace Microsoft.Extensions.DependencyInjection;
 
@@ -27,14 +29,37 @@ public interface ICacheStackBuilder
 	IList<ICacheExtension> Extensions { get; }
 }
 
-internal sealed class CacheStackBuilder : ICacheStackBuilder
+/// <inheritdoc/>
+/// <typeparam name="TContext">The type of context that is passed during the cache entry generation process.</typeparam>
+public interface ICacheStackBuilder<TContext> : ICacheStackBuilder
+{
+	/// <summary>
+	/// The activator that is used to resolve <typeparamref name="TContext"/> for the cache entry generation process.
+	/// </summary>
+	/// <remarks>
+	/// The default activator uses the current service collection as a means to instantiate <typeparamref name="TContext"/>.
+	/// </remarks>
+	public ICacheContextActivator CacheContextActivator { get; set; }
+}
+
+internal class CacheStackBuilder : ICacheStackBuilder
 {
 	/// <inheritdoc/>
 	public IList<ICacheLayer> CacheLayers { get; } = new List<ICacheLayer>();
 	/// <inheritdoc/>
 	public IList<ICacheExtension> Extensions { get; } = new List<ICacheExtension>();
 }
 
+internal sealed class CacheStackBuilder<TContext> : CacheStackBuilder, ICacheStackBuilder<TContext>
+{
+	/// <inheritdoc/>
+	public ICacheContextActivator CacheContextActivator { get; set; }
+
+	public CacheStackBuilder(ICacheContextActivator cacheContextActivator)
+	{
+		CacheContextActivator = cacheContextActivator;
+	}
+}
 
 /// <summary>
 /// Microsoft <see cref="IServiceCollection"/> extensions for Cache Tower.
@@ -49,20 +74,70 @@ private static void ThrowIfInvalidBuilder(ICacheStackBuilder builder)
 		}
 	}
 
+	private static ICacheStack BuildCacheStack(IServiceProvider provider, Action<IServiceProvider, ICacheStackBuilder> configureBuilder)
+	{
+		var builder = new CacheStackBuilder();
+		configureBuilder(provider, builder);
+		ThrowIfInvalidBuilder(builder);
+		return new CacheStack(
+			builder.CacheLayers.ToArray(),
+			builder.Extensions.ToArray()
+		);
+	}
+
+	private static ICacheStack<TContext> BuildCacheStack<TContext>(IServiceProvider provider, Action<IServiceProvider, ICacheStackBuilder<TContext>> configureBuilder)
+	{
+		var builder = new CacheStackBuilder<TContext>(new ServiceProviderContextActivator(provider));
+		configureBuilder(provider, builder);
+		ThrowIfInvalidBuilder(builder);
+		return new CacheStack<TContext>(
+			builder.CacheContextActivator,
+			builder.CacheLayers.ToArray(),
+			builder.Extensions.ToArray()
+		);
+	}
+
+	/// <inheritdoc cref="AddCacheStack(IServiceCollection, Action{IServiceProvider, ICacheStackBuilder})"/>
+	[EditorBrowsable(EditorBrowsableState.Never)]
+	public static void AddCacheStack(this IServiceCollection services, Action<ICacheStackBuilder> configureBuilder)
+	{
+		services.AddCacheStack((serviceProvider, builder) => configureBuilder(builder));
+	}
+
 	/// <summary>
 	/// Adds a <see cref="CacheStack"/> to the service collection.
 	/// </summary>
 	/// <param name="services"></param>
 	/// <param name="configureBuilder">The builder to configure the <see cref="CacheStack"/>.</param>
-	public static void AddCacheStack(this IServiceCollection services, Action<ICacheStackBuilder> configureBuilder)
+	public static void AddCacheStack(this IServiceCollection services, Action<IServiceProvider, ICacheStackBuilder> configureBuilder)
 	{
-		var builder = new CacheStackBuilder();
-		configureBuilder(builder);
-		ThrowIfInvalidBuilder(builder);
-		services.AddSingleton<ICacheStack>(sp => new CacheStack(
-			builder.CacheLayers.ToArray(),
-			builder.Extensions.ToArray()
-		));
+		services.AddSingleton(provider => BuildCacheStack(provider, configureBuilder));
+	}
+
+	/// <summary>
+	/// Adds a <see cref="ICacheStackAccessor"/> to the service collection and configures a named <see cref="CacheStack"/>.
+	/// </summary>
+	/// <param name="services"></param>
+	/// <param name="name">The name of the <see cref="CacheStack"/> to configure.</param>
+	/// <param name="configureBuilder">The builder to configure the <see cref="CacheStack"/>.</param>
+	public static void AddCacheStack(this IServiceCollection services, string name, Action<IServiceProvider, ICacheStackBuilder> configureBuilder)
+	{
+		services.TryAddSingleton<NamedCacheStackLookup>();
+		services.TryAddSingleton<ICacheStackAccessor, CacheStackAccessor>();
+		services.AddSingleton(provider =>
+		{
+			return new NamedCacheStackProvider(name, provider =>
+			{
+				return BuildCacheStack(provider, configureBuilder);
+			});
+		});
+	}
+
+	/// <inheritdoc cref="AddCacheStack{TContext}(IServiceCollection, Action{IServiceProvider, ICacheStackBuilder{TContext}})"/>
+	[EditorBrowsable(EditorBrowsableState.Never)]
+	public static void AddCacheStack<TContext>(this IServiceCollection services, Action<ICacheStackBuilder> configureBuilder)
+	{
+		services.AddCacheStack<TContext>((provider, builder) => configureBuilder(builder));
 	}
 
 	/// <summary>
@@ -74,16 +149,29 @@ public static void AddCacheStack(this IServiceCollection services, Action<ICache
 	/// <typeparam name="TContext"></typeparam>
 	/// <param name="services"></param>
 	/// <param name="configureBuilder">The builder to configure the <see cref="CacheStack"/>.</param>
-	public static void AddCacheStack<TContext>(this IServiceCollection services, Action<ICacheStackBuilder> configureBuilder)
+	public static void AddCacheStack<TContext>(this IServiceCollection services, Action<IServiceProvider, ICacheStackBuilder<TContext>> configureBuilder)
 	{
-		var builder = new CacheStackBuilder();
-		configureBuilder(builder);
-		ThrowIfInvalidBuilder(builder);
-		services.AddSingleton<ICacheStack<TContext>>(sp => new CacheStack<TContext>(
-			new ServiceProviderContextActivator(sp),
-			builder.CacheLayers.ToArray(),
-			builder.Extensions.ToArray()
-		));
+		services.AddSingleton(provider => BuildCacheStack(provider, configureBuilder));
+	}
+
+	/// <summary>
+	/// Adds a <see cref="ICacheStackAccessor{TContext}"/> to the service collection and configures a named <see cref="CacheStack{TContext}"/>.
+	/// </summary>
+	/// <param name="services"></param>
+	/// <param name="name">The name of the <see cref="CacheStack"/> to configure.</param>
+	/// <param name="configureBuilder">The builder to configure the <see cref="CacheStack"/>.</param>
+	public static void AddCacheStack<TContext>(this IServiceCollection services, string name, Action<IServiceProvider, ICacheStackBuilder<TContext>> configureBuilder)
+	{
+		services.TryAddSingleton<NamedCacheStackLookup>();
+		services.TryAddSingleton<ICacheStackAccessor, CacheStackAccessor>();
+		services.TryAddSingleton<ICacheStackAccessor<TContext>, CacheStackAccessor<TContext>>();
+		services.AddSingleton(provider =>
+		{
+			return new NamedCacheStackProvider(name, provider =>
+			{
+				return BuildCacheStack(provider, configureBuilder);
+			});
+		});
 	}
 
 	/// <summary>
@@ -93,16 +181,14 @@ public static void AddCacheStack<TContext>(this IServiceCollection services, Act
 	/// <param name="services"></param>
 	/// <param name="contextActivator">The activator to instantiate the <typeparamref name="TContext"/> during cache refreshing.</param>
 	/// <param name="configureBuilder">The builder to configure the <see cref="CacheStack"/>.</param>
+	[EditorBrowsable(EditorBrowsableState.Never)]
 	public static void AddCacheStack<TContext>(this IServiceCollection services, ICacheContextActivator contextActivator, Action<ICacheStackBuilder> configureBuilder)
 	{
-		var builder = new CacheStackBuilder();
-		configureBuilder(builder);
-		ThrowIfInvalidBuilder(builder);
-		services.AddSingleton<ICacheStack<TContext>>(sp => new CacheStack<TContext>(
-			contextActivator,
-			builder.CacheLayers.ToArray(),
-			builder.Extensions.ToArray()
-		));
+		services.AddSingleton(provider => BuildCacheStack<TContext>(provider, (provider, builder) =>
+		{
+			builder.CacheContextActivator = contextActivator;
+			configureBuilder(builder);
+		}));
 	}
 
 	/// <summary>