重构代码并抽取基础构建库

libraries/HelloShop.EventBus.RabbitMQ/HelloShop.EventBus.RabbitMQ.csproj

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+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <TargetFramework>net9.0</TargetFramework>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="Aspire.RabbitMQ.Client" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\HelloShop.EventBus.Abstractions\HelloShop.EventBus.Abstractions.csproj" />
+  </ItemGroup>
+
+</Project>

libraries/HelloShop.EventBus.RabbitMQ/RabbitMQEventBus.cs

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+// Copyright (c) HelloShop Corporation. All rights reserved.
+// See the license file in the project root for more information.
+
+using HelloShop.EventBus.Abstractions;
+using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.Hosting;
+using Microsoft.Extensions.Logging;
+using Microsoft.Extensions.Options;
+using Polly;
+using Polly.Retry;
+using RabbitMQ.Client;
+using RabbitMQ.Client.Events;
+using RabbitMQ.Client.Exceptions;
+using System.Net.Sockets;
+using System.Text;
+using System.Text.Json;
+
+namespace HelloShop.EventBus.RabbitMQ
+{
+    public sealed class RabbitMQEventBus(ILogger<RabbitMQEventBus> logger, IServiceProvider serviceProvider, IOptions<RabbitMQEventBusOptions> rabbitMQEventBusOptions, IOptions<EventBusOptions> eventBusOptions) : IEventBus, IDisposable, IHostedService
+    {
+        private readonly ResiliencePipeline _pipeline = CreateResiliencePipeline(rabbitMQEventBusOptions.Value.RetryCount);
+        private readonly string _queueName = rabbitMQEventBusOptions.Value.QueueName;
+        private readonly string _exchangeName = rabbitMQEventBusOptions.Value.ExchangeName;
+        private readonly EventBusOptions _eventBusOptions = eventBusOptions.Value;
+
+        private IConnection? _rabbitMQConnection;
+        private IModel? _consumerChannel;
+
+        public Task StartAsync(CancellationToken cancellationToken)
+        {
+            Task.Factory.StartNew(() =>
+            {
+                try
+                {
+                    _rabbitMQConnection = serviceProvider.GetRequiredService<IConnection>();
+                    _consumerChannel = _rabbitMQConnection.CreateModel();
+                    _consumerChannel.ExchangeDeclare(exchange: _exchangeName, type: ExchangeType.Direct);
+                    _consumerChannel.QueueDeclare(queue: _queueName, durable: true, exclusive: false, autoDelete: false, arguments: null);
+
+                    var consumer = new AsyncEventingBasicConsumer(_consumerChannel);
+                    consumer.Received += OnMessageReceivedAsync;
+                    _consumerChannel.BasicConsume(queue: _queueName, autoAck: false, consumer: consumer);
+
+                    foreach (var (eventName, _) in _eventBusOptions.EventTypes)
+                    {
+                        _consumerChannel.QueueBind(queue: _queueName, exchange: _exchangeName, routingKey: eventName);
+                    }
+                }
+                catch (Exception ex)
+                {
+                    logger.LogError(ex, "An error occurred while starting the RabbitMQ event bus.");
+                }
+            }, TaskCreationOptions.LongRunning);
+
+            return Task.CompletedTask;
+        }
+
+        public Task StopAsync(CancellationToken cancellationToken) => Task.CompletedTask;
+
+        public void Dispose() => _consumerChannel?.Dispose();
+
+        public Task PublishAsync(DistributedEvent @event, CancellationToken cancellationToken = default)
+        {
+            string routingKey = @event.GetType().Name;
+
+            using var channel = _rabbitMQConnection?.CreateModel() ?? throw new InvalidOperationException("RabbitMQ connection is not available.");
+
+            channel.ExchangeDeclare(exchange: _exchangeName, type: ExchangeType.Direct);
+
+            var body = JsonSerializer.SerializeToUtf8Bytes(@event, @event.GetType(), _eventBusOptions.JsonSerializerOptions);
+
+            return _pipeline.Execute(() =>
+            {
+                IBasicProperties properties = channel.CreateBasicProperties();
+                properties.DeliveryMode = 2;
+                channel.BasicPublish(exchange: _exchangeName, routingKey: routingKey, mandatory: true, basicProperties: properties, body: body);
+                return Task.CompletedTask;
+            });
+        }
+
+        private async Task OnMessageReceivedAsync(object sender, BasicDeliverEventArgs eventArgs)
+        {
+            string eventName = eventArgs.RoutingKey;
+            string message = Encoding.UTF8.GetString(eventArgs.Body.Span);
+
+            if (!_eventBusOptions.EventTypes.TryGetValue(eventName, out var eventType))
+            {
+                return;
+            }
+
+            await using var scope = serviceProvider.CreateAsyncScope();
+
+            var distributedEvent = JsonSerializer.Deserialize(message, eventType, _eventBusOptions.JsonSerializerOptions) as DistributedEvent;
+
+            foreach (var handler in scope.ServiceProvider.GetKeyedServices<IDistributedEventHandler>(eventType))
+            {
+                if (distributedEvent is not null)
+                {
+                    await handler.HandleAsync(distributedEvent);
+                }
+            }
+
+            _consumerChannel?.BasicAck(eventArgs.DeliveryTag, multiple: false);
+        }
+
+        private static ResiliencePipeline CreateResiliencePipeline(int retryCount)
+        {
+            var retryOptions = new RetryStrategyOptions
+            {
+                ShouldHandle = new PredicateBuilder().Handle<BrokerUnreachableException>().Handle<SocketException>(),
+                MaxRetryAttempts = retryCount,
+                DelayGenerator = (context) => ValueTask.FromResult(GenerateDelay(context.AttemptNumber))
+            };
+
+            return new ResiliencePipelineBuilder().AddRetry(retryOptions).Build();
+
+            static TimeSpan? GenerateDelay(int attempt) => TimeSpan.FromSeconds(Math.Pow(2, attempt));
+        }
+    }
+}

libraries/HelloShop.EventBus.RabbitMQ/RabbitMQEventBusExtensions.cs

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+// Copyright (c) HelloShop Corporation. All rights reserved.
+// See the license file in the project root for more information.
+
+using HelloShop.EventBus.Abstractions;
+using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.Hosting;
+
+namespace HelloShop.EventBus.RabbitMQ
+{
+    public static class RabbitMQEventBusExtensions
+    {
+        private const string DefaultSectionName = "RabbitMQEventBus";
+
+        public static IEventBusBuilder AddRabbitMqEventBus(this IHostApplicationBuilder builder, string connectionName, string sectionName = DefaultSectionName)
+        {
+            ArgumentNullException.ThrowIfNull(builder);
+
+            builder.AddRabbitMQClient(connectionName, configureConnectionFactory: factory =>
+            {
+                factory.DispatchConsumersAsync = true;
+            });
+
+            builder.Services.Configure<EventBusOptions>(builder.Configuration.GetSection(sectionName));
+
+            builder.Services.AddSingleton<IEventBus, RabbitMQEventBus>();
+            builder.Services.AddSingleton<IHostedService>(sp => (RabbitMQEventBus)sp.GetRequiredService<IEventBus>());
+
+            return new EventBusBuilder(builder.Services);
+        }
+
+        private class EventBusBuilder(IServiceCollection services) : IEventBusBuilder
+        {
+            public IServiceCollection Services => services;
+        }
+    }
+}

libraries/HelloShop.EventBus.RabbitMQ/RabbitMQEventBusOptions.cs

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+// Copyright (c) HelloShop Corporation. All rights reserved.
+// See the license file in the project root for more information.
+
+namespace HelloShop.EventBus.RabbitMQ
+{
+    public class RabbitMQEventBusOptions
+    {
+        public string ExchangeName { get; set; } = "event-bus-exchange";
+
+        public required string QueueName { get; set; }
+
+        public int RetryCount { get; set; } = 10;
+    }
+}