126 lines
4.2 KiB
C#
126 lines
4.2 KiB
C#
using NewLife.Caching.Queues;
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using NewLife.Log;
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using NewLife.Messaging;
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using System.Diagnostics.CodeAnalysis;
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namespace NewLife.Caching.Services;
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/// <summary>Redis事件上下文</summary>
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public class RedisEventContext<TEvent>(IEventBus<TEvent> eventBus, Queues.Message message) : IEventContext<TEvent>
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{
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/// <summary>事件总线</summary>
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public IEventBus<TEvent> EventBus { get; set; } = eventBus;
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/// <summary>原始消息</summary>
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public Queues.Message Message { get; set; } = message;
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}
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/// <summary>Redis事件总线</summary>
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/// <typeparam name="TEvent"></typeparam>
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/// <remarks>实例化消息队列事件总线</remarks>
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public class RedisEventBus<TEvent>(FullRedis cache, String topic, String group) : EventBus<TEvent>
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{
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private RedisStream<TEvent>? _queue;
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private CancellationTokenSource? _source;
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/// <summary>销毁</summary>
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/// <param name="disposing"></param>
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protected override void Dispose(Boolean disposing)
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{
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base.Dispose(disposing);
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_source?.TryDispose();
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}
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/// <summary>初始化</summary>
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[MemberNotNull(nameof(_queue))]
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protected virtual void Init()
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{
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if (_queue != null) return;
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// 创建Stream队列，指定消费组，从最后位置开始消费
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var stream = cache.GetStream<TEvent>(topic);
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stream.Group = group;
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stream.FromLastOffset = true;
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stream.Expire = TimeSpan.FromDays(3);
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_queue = stream;
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if (_source != null)
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_ = Task.Run(() => ConsumeMessage(_source));
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}
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/// <summary>发布消息到消息队列</summary>
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/// <param name="event">事件</param>
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/// <param name="context">上下文</param>
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/// <param name="cancellationToken">取消令牌</param>
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public override Task<Int32> PublishAsync(TEvent @event, IEventContext<TEvent>? context = null, CancellationToken cancellationToken = default)
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{
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Init();
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var rs = _queue.Add(@event);
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return Task.FromResult(1);
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}
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/// <summary>订阅消息。启动大循环，从消息队列订阅消息，再分发到本地订阅者</summary>
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/// <param name="handler">处理器</param>
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/// <param name="clientId">客户标识。每个客户只能订阅一次，重复订阅将会挤掉前一次订阅</param>
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public override Boolean Subscribe(IEventHandler<TEvent> handler, String clientId = "")
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{
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if (_source == null)
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{
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var source = new CancellationTokenSource();
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if (Interlocked.CompareExchange(ref _source, source, null) == null)
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{
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Init();
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}
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}
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// 本进程订阅。从队列中消费到消息时，会发布到本进程的事件总线，这里订阅可以让目标处理器直接收到消息
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return base.Subscribe(handler, clientId);
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}
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/// <summary>从队列中消费消息，经事件总线送给设备会话</summary>
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/// <param name="source"></param>
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/// <returns></returns>
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protected virtual async Task ConsumeMessage(CancellationTokenSource source)
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{
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DefaultSpan.Current = null;
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var cancellationToken = source.Token;
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var stream = _queue!;
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try
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{
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if (!stream.Group.IsNullOrEmpty()) stream.SetGroup(stream.Group);
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while (!cancellationToken.IsCancellationRequested)
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{
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var msg = await stream!.TakeMessageAsync(15, cancellationToken).ConfigureAwait(false);
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if (msg != null)
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{
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var msg2 = msg.GetBody<TEvent>();
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if (msg2 != null)
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{
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// 发布到事件总线
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await base.PublishAsync(msg2, new RedisEventContext<TEvent>(this, msg), cancellationToken).ConfigureAwait(false);
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}
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}
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else
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{
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await Task.Delay(1_000, cancellationToken).ConfigureAwait(false);
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}
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}
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}
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catch (TaskCanceledException) { }
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catch (OperationCanceledException) { }
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catch (Exception ex)
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{
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XTrace.WriteException(ex);
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}
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finally
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{
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source.Cancel();
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_queue = null;
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}
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}
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}
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