| | | 1 | | using Microsoft.Extensions.Hosting; |
| | | 2 | | using Microsoft.Extensions.Logging; |
| | | 3 | | using Microsoft.Extensions.Options; |
| | | 4 | | |
| | | 5 | | namespace AsyncResponse.Transports.SQS; |
| | | 6 | | |
| | | 7 | | internal abstract class SqsSubscriberService : BackgroundService |
| | | 8 | | { |
| | | 9 | | private readonly ISqsClient _client; |
| | | 10 | | |
| | | 11 | | protected SqsSubscriberService( |
| | | 12 | | IOptions<SqsAsyncResponseOptions> options, |
| | | 13 | | ISqsClient client, |
| | | 14 | | ILogger logger) |
| | | 15 | | { |
| | | 16 | | Options = options.Value; |
| | | 17 | | SqsOptionsValidator.ValidateCommon(Options); |
| | | 18 | | _client = client; |
| | | 19 | | Logger = logger; |
| | | 20 | | } |
| | | 21 | | |
| | | 22 | | protected SqsAsyncResponseOptions Options { get; } |
| | | 23 | | protected ILogger Logger { get; } |
| | | 24 | | |
| | | 25 | | protected abstract string QueueName { get; } |
| | | 26 | | protected abstract SqsSubscriberOptions SubscriberOptions { get; } |
| | | 27 | | protected abstract SqsSubscriberRole SubscriberRole { get; } |
| | | 28 | | /// <summary>Handles the delivered message.</summary> |
| | | 29 | | protected abstract Task HandleMessageAsync(SqsTransportDelivery delivery, CancellationToken cancellationToken); |
| | | 30 | | |
| | | 31 | | /// <summary>Runs this background operation until cancellation is requested.</summary> |
| | | 32 | | protected override async Task ExecuteAsync(CancellationToken stoppingToken) |
| | | 33 | | { |
| | | 34 | | var queue = QueueName; |
| | | 35 | | SqsMessageDispatcher.ValidateOptions(Options, SubscriberOptions, SubscriberRole); |
| | | 36 | | var failures = 0; |
| | | 37 | | |
| | | 38 | | while (!stoppingToken.IsCancellationRequested) |
| | | 39 | | { |
| | | 40 | | try |
| | | 41 | | { |
| | | 42 | | await RunSubscriberAsync(queue, stoppingToken).ConfigureAwait(false); |
| | | 43 | | return; |
| | | 44 | | } |
| | | 45 | | catch (OperationCanceledException) when (stoppingToken.IsCancellationRequested) |
| | | 46 | | { |
| | | 47 | | return; |
| | | 48 | | } |
| | | 49 | | catch (Exception ex) when (!stoppingToken.IsCancellationRequested) |
| | | 50 | | { |
| | | 51 | | failures++; |
| | | 52 | | var retryDelay = AsyncResponseRetry.Backoff( |
| | | 53 | | failures, |
| | | 54 | | Options.SubscriberRetryBaseDelay, |
| | | 55 | | Options.SubscriberRetryMaxDelay); |
| | | 56 | | Logger.LogWarning( |
| | | 57 | | ex, |
| | | 58 | | "SQS subscriber failed for queue {Queue} ({Role}); retrying in {RetryDelay}.", |
| | | 59 | | queue, |
| | | 60 | | SubscriberRole, |
| | | 61 | | retryDelay); |
| | | 62 | | await Task.Delay(retryDelay, stoppingToken).ConfigureAwait(false); |
| | | 63 | | } |
| | | 64 | | } |
| | | 65 | | } |
| | | 66 | | |
| | | 67 | | private async Task RunSubscriberAsync(string queue, CancellationToken stoppingToken) |
| | | 68 | | { |
| | | 69 | | // A queue configured by name resolves through GetQueueUrl; failures here (queue not yet |
| | | 70 | | // provisioned, endpoint still starting) surface to the retry loop above. |
| | | 71 | | var queueUrl = SqsQueueAddress.IsUrl(queue) |
| | | 72 | | ? queue |
| | | 73 | | : await _client.GetQueueUrlAsync(queue, stoppingToken).ConfigureAwait(false); |
| | | 74 | | |
| | | 75 | | await using var dispatcher = SqsMessageDispatcher.Create( |
| | | 76 | | HandleMessageAsync, |
| | | 77 | | Options, |
| | | 78 | | SubscriberOptions, |
| | | 79 | | Logger, |
| | | 80 | | queue, |
| | | 81 | | SubscriberRole); |
| | | 82 | | |
| | | 83 | | Logger.LogInformation( |
| | | 84 | | "SQS subscriber started. Queue: {Queue}. Role: {Role}. AckMode: {AckMode}.", |
| | | 85 | | queue, |
| | | 86 | | SubscriberRole, |
| | | 87 | | SubscriberOptions.AckMode); |
| | | 88 | | |
| | | 89 | | while (!stoppingToken.IsCancellationRequested) |
| | | 90 | | { |
| | | 91 | | // In early-ACK mode, receiving while the background queue is saturated would burn the |
| | | 92 | | // queue's redrive policy (SQS counts every receive), so wait for free capacity and never |
| | | 93 | | // request more messages than the dispatcher can accept. |
| | | 94 | | await dispatcher.WaitForCapacityAsync(stoppingToken).ConfigureAwait(false); |
| | | 95 | | var maxMessages = Math.Min(Options.MaxMessagesPerReceive, dispatcher.FreeCapacity); |
| | | 96 | | |
| | | 97 | | var deliveries = await _client.ReceiveMessagesAsync( |
| | | 98 | | new SqsReceiveRequest( |
| | | 99 | | queueUrl, |
| | | 100 | | maxMessages, |
| | | 101 | | Options.ReceiveWaitTime, |
| | | 102 | | SubscriberOptions.VisibilityTimeout), |
| | | 103 | | stoppingToken).ConfigureAwait(false); |
| | | 104 | | |
| | | 105 | | await DispatchBatchAsync(dispatcher, deliveries, queue, stoppingToken).ConfigureAwait(false); |
| | | 106 | | } |
| | | 107 | | } |
| | | 108 | | |
| | | 109 | | private async Task DispatchBatchAsync( |
| | | 110 | | SqsMessageDispatcher dispatcher, |
| | | 111 | | IReadOnlyList<SqsTransportDelivery> deliveries, |
| | | 112 | | string queue, |
| | | 113 | | CancellationToken stoppingToken) |
| | | 114 | | { |
| | | 115 | | if (deliveries.Count == 0) |
| | | 116 | | return; |
| | | 117 | | |
| | | 118 | | if (SubscriberOptions.AckMode is not SqsAckMode.AckAfterHandlerCompletes |
| | | 119 | | || SubscriberOptions.VisibilityRenewalInterval is not { } renewalInterval |
| | | 120 | | || SubscriberOptions.VisibilityTimeout is not { } visibilityTimeout) |
| | | 121 | | { |
| | | 122 | | foreach (var delivery in deliveries) |
| | | 123 | | await dispatcher.HandleAsync(delivery, stoppingToken).ConfigureAwait(false); |
| | | 124 | | return; |
| | | 125 | | } |
| | | 126 | | |
| | | 127 | | // The batch is processed serially, so a slow handler lets the visibility timeout of the later |
| | | 128 | | // (still unprocessed) messages lapse and a competing consumer processes them a second time. |
| | | 129 | | // While the batch is in flight, a heartbeat resets every unsettled message's invisibility to |
| | | 130 | | // the configured visibility timeout. |
| | | 131 | | var progress = new BatchProgress(deliveries.Count); |
| | | 132 | | using var renewalCancellation = CancellationTokenSource.CreateLinkedTokenSource(stoppingToken); |
| | | 133 | | var renewalTask = RenewVisibilityLoopAsync( |
| | | 134 | | deliveries, |
| | | 135 | | progress, |
| | | 136 | | renewalInterval, |
| | | 137 | | visibilityTimeout, |
| | | 138 | | queue, |
| | | 139 | | renewalCancellation.Token); |
| | | 140 | | try |
| | | 141 | | { |
| | | 142 | | for (var index = 0; index < deliveries.Count; index++) |
| | | 143 | | { |
| | | 144 | | var delivery = deliveries[index]; |
| | | 145 | | var batchIndex = index; |
| | | 146 | | // The dispatcher's failure path shortens visibility to RedeliveryDelay while the |
| | | 147 | | // heartbeat still counts the message as unsettled (MarkSettled runs only after |
| | | 148 | | // HandleAsync returns). Routing the dispatcher's visibility changes through a |
| | | 149 | | // suppression mark — set before the change itself — keeps a racing heartbeat from |
| | | 150 | | // stretching that fast retry back out to the full visibility timeout. |
| | | 151 | | var tracked = delivery with |
| | | 152 | | { |
| | | 153 | | ChangeVisibilityAsync = timeout => |
| | | 154 | | { |
| | | 155 | | progress.SuppressRenewal(batchIndex); |
| | | 156 | | return delivery.ChangeVisibilityAsync(timeout); |
| | | 157 | | } |
| | | 158 | | }; |
| | | 159 | | try |
| | | 160 | | { |
| | | 161 | | await dispatcher.HandleAsync(tracked, stoppingToken).ConfigureAwait(false); |
| | | 162 | | } |
| | | 163 | | finally |
| | | 164 | | { |
| | | 165 | | progress.MarkSettled(); |
| | | 166 | | } |
| | | 167 | | } |
| | | 168 | | } |
| | | 169 | | finally |
| | | 170 | | { |
| | | 171 | | renewalCancellation.Cancel(); |
| | | 172 | | await renewalTask.ConfigureAwait(false); |
| | | 173 | | } |
| | | 174 | | } |
| | | 175 | | |
| | | 176 | | private async Task RenewVisibilityLoopAsync( |
| | | 177 | | IReadOnlyList<SqsTransportDelivery> deliveries, |
| | | 178 | | BatchProgress progress, |
| | | 179 | | TimeSpan renewalInterval, |
| | | 180 | | TimeSpan visibilityTimeout, |
| | | 181 | | string queue, |
| | | 182 | | CancellationToken cancellationToken) |
| | | 183 | | { |
| | | 184 | | try |
| | | 185 | | { |
| | | 186 | | while (true) |
| | | 187 | | { |
| | | 188 | | await Task.Delay(renewalInterval, cancellationToken).ConfigureAwait(false); |
| | | 189 | | |
| | | 190 | | // Renew from the first unsettled message onward: that covers the message currently in |
| | | 191 | | // the handler plus everything still waiting its turn. Two settle paths race this |
| | | 192 | | // sweep, and only one of them is harmless. A handled message was deleted, so a late |
| | | 193 | | // renewal merely fails and is logged — SQS redelivery keeps at-least-once intact. A |
| | | 194 | | // failed message was NOT deleted (its receipt handle stays live) and already carries |
| | | 195 | | // the failure path's shortened RedeliveryDelay, so a late renewal here would SUCCEED |
| | | 196 | | // and stretch that fast retry back out to the full visibility timeout — the |
| | | 197 | | // suppression mark and the per-message re-read of the settled prefix keep the sweep |
| | | 198 | | // away from it. |
| | | 199 | | for (var i = progress.SettledCount; i < deliveries.Count; i++) |
| | | 200 | | { |
| | | 201 | | if (i < progress.SettledCount || progress.IsRenewalSuppressed(i)) |
| | | 202 | | continue; |
| | | 203 | | |
| | | 204 | | var delivery = deliveries[i]; |
| | | 205 | | try |
| | | 206 | | { |
| | | 207 | | await delivery.ChangeVisibilityAsync(visibilityTimeout).ConfigureAwait(false); |
| | | 208 | | } |
| | | 209 | | catch (Exception ex) |
| | | 210 | | { |
| | | 211 | | Logger.LogWarning( |
| | | 212 | | ex, |
| | | 213 | | "Failed to renew visibility of SQS message {MessageId} on {Queue}; it may redeliver while st |
| | | 214 | | delivery.MessageId, |
| | | 215 | | queue); |
| | | 216 | | } |
| | | 217 | | } |
| | | 218 | | } |
| | | 219 | | } |
| | | 220 | | catch (OperationCanceledException) |
| | | 221 | | { |
| | | 222 | | // The batch finished or the subscriber is stopping. |
| | | 223 | | } |
| | | 224 | | } |
| | | 225 | | |
| | | 226 | | private sealed class BatchProgress |
| | | 227 | | { |
| | | 228 | | // One slot per batch message. Settled and suppressed only ever transition false→true, so |
| | | 229 | | // monotonic volatile writes/reads are enough — no lock, and a stale read only delays a |
| | | 230 | | // skip by one sweep pass. |
| | | 231 | | private readonly bool[] _renewalSuppressed; |
| | | 232 | | private int _settledCount; |
| | | 233 | | |
| | | 234 | | public BatchProgress(int batchSize) => _renewalSuppressed = new bool[batchSize]; |
| | | 235 | | |
| | | 236 | | public int SettledCount => Volatile.Read(ref _settledCount); |
| | | 237 | | |
| | | 238 | | public void MarkSettled() => Interlocked.Increment(ref _settledCount); |
| | | 239 | | |
| | | 240 | | /// <summary>Marks the message at <paramref name="index"/> as owning its own visibility; the renewal sweep must |
| | | 241 | | public void SuppressRenewal(int index) => Volatile.Write(ref _renewalSuppressed[index], true); |
| | | 242 | | |
| | | 243 | | public bool IsRenewalSuppressed(int index) => Volatile.Read(ref _renewalSuppressed[index]); |
| | | 244 | | } |
| | | 245 | | } |
| | | 246 | | |
| | | 247 | | internal sealed class SqsWorkerSubscriber : SqsSubscriberService |
| | | 248 | | { |
| | | 249 | | private readonly IAsyncResponseIngress _ingress; |
| | | 250 | | |
| | | 251 | | /// <summary>Creates a worker subscriber for the configured SQS worker queue.</summary> |
| | | 252 | | public SqsWorkerSubscriber( |
| | | 253 | | IOptions<SqsAsyncResponseOptions> options, |
| | | 254 | | ISqsClient client, |
| | | 255 | | IAsyncResponseIngress ingress, |
| | | 256 | | ILogger<SqsWorkerSubscriber> logger) |
| | | 257 | | : base(options, client, logger) |
| | | 258 | | { |
| | | 259 | | _ingress = ingress; |
| | | 260 | | } |
| | | 261 | | |
| | | 262 | | protected override string QueueName |
| | | 263 | | => SqsOptionsValidator.Required(Options.WorkerQueue, nameof(Options.WorkerQueue)); |
| | | 264 | | |
| | | 265 | | protected override SqsSubscriberOptions SubscriberOptions => Options.WorkerSubscriber; |
| | | 266 | | protected override SqsSubscriberRole SubscriberRole => SqsSubscriberRole.Worker; |
| | | 267 | | |
| | | 268 | | /// <summary>Handles the delivered message.</summary> |
| | | 269 | | protected override Task HandleMessageAsync(SqsTransportDelivery delivery, CancellationToken cancellationToken) |
| | | 270 | | => _ingress.HandleWorkerMessageAsync(delivery.Body); |
| | | 271 | | } |
| | | 272 | | |
| | | 273 | | internal sealed class SqsResponseIngressSubscriber : SqsSubscriberService |
| | | 274 | | { |
| | | 275 | | private readonly IAsyncResponseIngress _ingress; |
| | | 276 | | |
| | | 277 | | /// <summary>Creates a response subscriber for the configured SQS response queue.</summary> |
| | | 278 | | public SqsResponseIngressSubscriber( |
| | | 279 | | IOptions<SqsAsyncResponseOptions> options, |
| | | 280 | | ISqsClient client, |
| | | 281 | | IAsyncResponseIngress ingress, |
| | | 282 | | ILogger<SqsResponseIngressSubscriber> logger) |
| | 3 | 283 | | : base(options, client, logger) |
| | | 284 | | { |
| | 3 | 285 | | _ingress = ingress; |
| | 3 | 286 | | } |
| | | 287 | | |
| | | 288 | | protected override string QueueName |
| | 3 | 289 | | => SqsOptionsValidator.Required(Options.ResponseQueue, nameof(Options.ResponseQueue)); |
| | | 290 | | |
| | 3 | 291 | | protected override SqsSubscriberOptions SubscriberOptions => Options.ResponseSubscriber; |
| | 3 | 292 | | protected override SqsSubscriberRole SubscriberRole => SqsSubscriberRole.ResponseIngress; |
| | | 293 | | |
| | | 294 | | /// <summary>Handles the delivered message.</summary> |
| | | 295 | | protected override Task HandleMessageAsync(SqsTransportDelivery delivery, CancellationToken cancellationToken) |
| | | 296 | | { |
| | 3 | 297 | | var correlationId = SqsCorrelationIdExtractor.Extract(delivery, delivery.Body, Options); |
| | 3 | 298 | | return _ingress.HandleResponseMessageAsync(delivery.Body, correlationId); |
| | | 299 | | } |
| | | 300 | | } |