PlacementStrategyExtensions.cs

using System;
using Microsoft.Extensions.DependencyInjection;
using Orleans.Runtime;
using Orleans.Runtime.Placement;

namespace Orleans.Hosting
{
    /// <summary>
    /// Extensions for configuring grain placement.
    /// </summary>
    public static class PlacementStrategyExtensions
    {
        /// <summary>
        /// Configures a <typeparamref name="TDirector"/> as the placement director for placement strategy <typeparamref name="TStrategy"/>.
        /// </summary>
        /// <typeparam name="TStrategy">The placement strategy.</typeparam>
        /// <typeparam name="TDirector">The placement director.</typeparam>
        /// <param name="builder">The builder.</param>
        /// <returns>The builder.</returns>
        public static ISiloHostBuilder AddPlacementDirector<TStrategy, TDirector>(this ISiloHostBuilder builder)
            where TStrategy : PlacementStrategy
            where TDirector : class, IPlacementDirector
        {
            return builder.ConfigureServices(services => services.AddPlacementDirector<TStrategy, TDirector>());
        }

        /// <summary>
        /// Adds a placement director.
        /// </summary>
        /// <typeparam name="TStrategy">The placement strategy.</typeparam>
        /// <param name="builder">The builder.</param>
        /// <param name="createDirector">The delegate used to create the placement director.</param>
        /// <returns>The builder.</returns>
        public static ISiloHostBuilder AddPlacementDirector<TStrategy>(this ISiloHostBuilder builder, Func<IServiceProvider, IPlacementDirector> createDirector)
            where TStrategy : PlacementStrategy
        {
            return builder.ConfigureServices(services => services.AddPlacementDirector<TStrategy>(createDirector));
        }

        /// <summary>
        /// Configures a <typeparamref name="TDirector"/> as the placement director for placement strategy <typeparamref name="TStrategy"/>.
        /// </summary>
        /// <typeparam name="TStrategy">The placement strategy.</typeparam>
        /// <typeparam name="TDirector">The placement director.</typeparam>
        /// <param name="builder">The builder.</param>
        /// <returns>The builder.</returns>
        public static ISiloBuilder AddPlacementDirector<TStrategy, TDirector>(this ISiloBuilder builder)
            where TStrategy : PlacementStrategy
            where TDirector : class, IPlacementDirector
        {
            return builder.ConfigureServices(services => services.AddPlacementDirector<TStrategy, TDirector>());
        }

        /// <summary>
        /// Adds a placement director.
        /// </summary>
        /// <typeparam name="TStrategy">The placement strategy.</typeparam>
        /// <param name="builder">The builder.</param>
        /// <param name="createDirector">The delegate used to create the placement director.</param>
        /// <returns>The builder.</returns>
        public static ISiloBuilder AddPlacementDirector<TStrategy>(this ISiloBuilder builder, Func<IServiceProvider, IPlacementDirector> createDirector)
            where TStrategy : PlacementStrategy
        {
            return builder.ConfigureServices(services => services.AddPlacementDirector<TStrategy>(createDirector));
        }

        internal static void AddPlacementDirector<TStrategy, TDirector>(this IServiceCollection services)
            where TStrategy : PlacementStrategy
            where TDirector : class, IPlacementDirector
        {
            services.AddSingletonNamedService<PlacementStrategy, TStrategy>(typeof(TStrategy).Name);
            services.AddSingletonKeyedService<Type, IPlacementDirector, TDirector>(typeof(TStrategy));
        }

        private static void AddPlacementDirector<TStrategy>(this IServiceCollection services, Func<IServiceProvider, IPlacementDirector> createDirector)
            where TStrategy : PlacementStrategy
        {
            services.AddSingletonNamedService<PlacementStrategy, TStrategy>(typeof(TStrategy).Name);
            services.AddSingletonKeyedService<Type, IPlacementDirector>(typeof(TStrategy), (sp, type) => createDirector(sp));
        }
    }
}