/// <summary>
/// adjusts the batch delay according to success rate and thresholds
/// we're focusing on batch delay here but batch size can also be adjusted
/// </summary>
/// <param name="restQueue">the rest queue instance</param>
/// <param name="minBatchDelay">the minimum batch delay that would like to have, don't have this too low as it will consume more CPU</param>
/// <param name="maxBatchDelay">the maximum batch delay that we can afford</param>
/// <param name="minSuccessRate">minimum success rate to adjustment</param>
/// <param name="maxSuccessRate">maximum success rate to adjustment</param>
private static void AdjustQueue(RestQueue.Queue restQueue, double minBatchDelay, double maxBatchDelay, int minSuccessRate, int maxSuccessRate)
{
double batchDelay = restQueue.BatchDelay.TotalMilliseconds;
if (successfulCount > 0)
{
var rate = GetSuccessRate();
// if we're below the success rate that we're looking for and the batch delay can be adjusted then try to increase it by 10%
if (rate < minSuccessRate && batchDelay < maxBatchDelay)
{
Trace.WriteLine("success rate too low, increasing batch delay");
// increase delay
restQueue.BatchDelay = TimeSpan.FromMilliseconds(Math.Min((batchDelay + maxBatchDelay) / 2, maxBatchDelay));
}
// if we're above the success rate that we're looking for, we have pending requests and the batch delay can be adjusted then try to decrease it by 10%
if (rate > maxSuccessRate && restQueue.Pending > 0 && batchDelay < minBatchDelay)
{
Trace.WriteLine("success rate too high, decreasing batch delay");
// decrease delay
restQueue.BatchDelay = TimeSpan.FromMilliseconds(Math.Max((batchDelay + minBatchDelay) / 2, minBatchDelay));
}
}
}
static void Main(string[] args)
{
Log log;
// we'll give a head start to the server so it'll be ready before the first request
Thread.Sleep(2000);
var restQueue = new RestQueue.Queue(new Uri("http://localhost:52159/api/"), handler)
{
RequestTimeout = TimeSpan.FromSeconds(10),
FixedRetryDelay = TimeSpan.FromMilliseconds(500),
BatchSize = 100,
BatchDelay = TimeSpan.FromSeconds(1)
};
// event listeners
restQueue.OnRequestError += (ex, timeout) =>
{
if (ex != null && !string.IsNullOrEmpty(ex.Message))
{
Trace.WriteLine(ex.Message);
}
Interlocked.Increment(ref errorCount);
};
restQueue.OnHttpError += statusCode => Interlocked.Increment(ref httpErrorCount);
restQueue.OnRequestSent += () => Interlocked.Increment(ref successfulCount);
// add requests to queue
Task.Run(() =>
{
for (int i = 0; i < 10000; i++)
{
log = new Log()
{
Timestamp = DateTime.Now,
Message = "test " + i
};
restQueue.Enqueue("logs/", log);
}
Trace.WriteLine("added all requests to queue");
});
// trace a status every second
Task.Run(() =>
{
while (true)
{
Trace.WriteLine($"success rate: {GetSuccessRate()}%, " +
$"pending: {restQueue.Pending}, " +
$"successful: {successfulCount}, " +
$"retry: {errorCount + httpErrorCount}, " +
$"errors: {errorCount}, " +
$"HTTP errors: { httpErrorCount}, " +
$"requests in queue { restQueue.Count}");
Thread.Sleep(1000);
}
});
// adjust the queue settings automatically according to performance
Task.Run(() =>
{
while (true)
{
// we're intentionally failing some of the request on the server to simulate real usage so the highest possible success rate for this test is about %80
AdjustQueue(restQueue, 100, 60000, 95, 75);
// sample the queue again after half of the delay has taken place to see if anything approved
// we want to gradually react to changes
Thread.Sleep((int)restQueue.BatchDelay.TotalMilliseconds / 2);
}
});
Console.ReadKey();
Trace.WriteLine("stopping processing..");
restQueue.Stop();
Trace.WriteLine($"done");
}
