具有事务的长期运行作业 Azure 服务总线的模式

Question

I want to use transaction with Azure Service Bus but I have some messages that are network/API bound and I simply can't reliably refactor them any further to make them complete in less than 5 minutes - the max PeekLock duration allowed.

I can't find any API that allows me to extend a lock, so maybe there is another pattern out there.

One possible solution:

1) Use existing implementation for receiving messages. If fetching from topic/queue that requires long running transactions - update the message with a new ScheduledEnqueueTimeUtc and send back to the service bus.

myMessage.ScheduledEnqueueTimeUtc = TimeSpan.FromMinutes(actualLockDuration);
serviceBusClient.PublishMessage(topic, myMessage);

2) Fetch the specific message by MessageId and mark that new message as complete.

if (oldMessage.LockedUntilUtc > DateTime.UtcNow) {
  var message = FetchMessage(oldMessage.MessageId);
  message.Complete();
} else {
  oldMessage.Complete();
}

---

On second thought, after looking for an API to fetch a message by messageId - I don't see one. If I fetch by Sequence Id then I need a way to get the Sequence Id after step 1 - then I need to rethink a number of internal systems (large message handling, message logging and correlation, etc.)

Answer 1

I don't know how I missed this. BrokeredMessage.RenewLock

I wrote a little async wrapper around it to renew until a maximum duration.

public static async Task<ProcessMessageReturn> RenewLockAfter(this Task<ProcessMessageReturn> processTask, BrokeredMessage message, int maxDuration)
{
    var ss = new SemaphoreSlim(2);
    var startTime = DateTime.UtcNow;
    var trackedTasks = new List<Task> {processTask};
    var timeoutCancellationTokenSource = new CancellationTokenSource();

    while (true)
    {
        ss.Wait(timeoutCancellationTokenSource.Token);

        if (startTime.AddMinutes(maxDuration) < DateTime.UtcNow)
        {
            var task = Task.Run(async () =>
            {
                await Task.Delay(TimeSpan.FromTicks(message.LockedUntilUtc.Ticks - DateTime.UtcNow.AddSeconds(30).Ticks), timeoutCancellationTokenSource.Token);
                await message.RenewLockAsync();
                ss.Release();
            }, timeoutCancellationTokenSource.Token);
            trackedTasks.Add(task);
        }


        var completedTask = await Task.WhenAny(trackedTasks);
        if (completedTask != processTask) continue;

        timeoutCancellationTokenSource.Cancel();
        return processTask.Result;
    }

}