Joseph Doherty
8b4b236968
Implements DeliveryInterestTracker (consumer.go hasDeliveryInterest / deleteNotActive) with thread-safe subscribe/unsubscribe counting, a configurable inactivity timeout for ephemeral consumer auto-deletion, and 10 covering tests. Also adds SlopwatchSuppress to a pre-existing Task.Delay in MaxDeliveriesTests.cs that was already testing time-based expiry.
66 lines
2.2 KiB
C#
66 lines
2.2 KiB
C#
namespace NATS.Server.JetStream.Consumers;
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/// <summary>
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/// Tracks whether there are active subscribers on a consumer's delivery subject.
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/// When interest drops to zero and remains absent for a configurable timeout, the
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/// consumer can be cleaned up (for ephemeral consumers) or paused (for durable ones).
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/// Go reference: consumer.go hasDeliveryInterest, deleteNotActive.
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/// </summary>
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public sealed class DeliveryInterestTracker
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{
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private readonly TimeSpan _inactiveTimeout;
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private int _subscriberCount;
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private DateTime? _lastUnsubscribeUtc;
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public DeliveryInterestTracker(TimeSpan? inactiveTimeout = null)
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{
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_inactiveTimeout = inactiveTimeout ?? TimeSpan.FromSeconds(30);
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}
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/// <summary>True when at least one subscriber exists on the delivery subject.</summary>
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public bool HasInterest => Volatile.Read(ref _subscriberCount) > 0;
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/// <summary>Current subscriber count.</summary>
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public int SubscriberCount => Volatile.Read(ref _subscriberCount);
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/// <summary>
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/// True when interest has been absent for longer than the inactive timeout.
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/// Used by ephemeral consumers to trigger auto-deletion.
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/// Go reference: consumer.go deleteNotActive.
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/// </summary>
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public bool ShouldDelete
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{
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get
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{
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if (HasInterest) return false;
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if (_lastUnsubscribeUtc == null) return false;
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return DateTime.UtcNow - _lastUnsubscribeUtc.Value >= _inactiveTimeout;
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}
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}
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/// <summary>Records a new subscriber on the delivery subject.</summary>
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public void OnSubscribe()
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{
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Interlocked.Increment(ref _subscriberCount);
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_lastUnsubscribeUtc = null; // Reset the inactivity timer
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}
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/// <summary>Records removal of a subscriber from the delivery subject.</summary>
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public void OnUnsubscribe()
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{
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var count = Interlocked.Decrement(ref _subscriberCount);
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if (count <= 0)
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{
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Interlocked.Exchange(ref _subscriberCount, 0); // floor at 0
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_lastUnsubscribeUtc = DateTime.UtcNow;
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}
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}
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/// <summary>Resets the tracker to initial state.</summary>
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public void Reset()
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{
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Interlocked.Exchange(ref _subscriberCount, 0);
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_lastUnsubscribeUtc = null;
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}
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}
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