// TODO(mathip): add support for requestId parsing.
public async Task <string> GetFilenameAsync(string request)
{
var client = await _lookupDispatcher.TakeAsync();
var filename = Path.GetRandomFileName();
var binaryWriter = new BinaryWriter(File.Open(filename, FileMode.OpenOrCreate));
var ct = new CancellationTokenSource(_timeout);
var res = new TaskCompletionSource <string>();
ct.Token.Register(() => res.TrySetCanceled(), false);
void SocketClientOnMessageReceived(object sender, SocketMessageEventArgs args)
{
// check for errors
if (args.Message[0] == IQFeedDefault.PrototolErrorCharacter && args.Message[1] == IQFeedDefault.ProtocolDelimiterCharacter)
{
// at this level, we might have true negative, further checks needed
var received = Encoding.ASCII.GetString(args.Message, 0, args.Count);
var messages = received.SplitFeedLine();
var errorMessage = ParseErrorMessage(messages);
if (!string.IsNullOrEmpty(errorMessage))
{
// error has been confirmed
res.TrySetException(_exceptionFactory.CreateNew(request, errorMessage, received));
return;
}
}
binaryWriter.Write(args.Message, 0, args.Count);
// check if the message end
if (args.Message.EndsWith(args.Count, _endOfMsgBytes))
{
res.TrySetResult(filename);
}
}
client.MessageReceived += SocketClientOnMessageReceived;
await _lookupRateLimiter.WaitAsync().ConfigureAwait(false);
client.Send(request);
await res.Task.ContinueWith(x =>
{
binaryWriter.Close();
client.MessageReceived -= SocketClientOnMessageReceived;
_lookupDispatcher.Add(client);
ct.Dispose();
if (res.Task.IsFaulted)
{
File.Delete(filename);
}
}, TaskContinuationOptions.None).ConfigureAwait(false);
return(await res.Task.ConfigureAwait(false));
}
protected async Task <IEnumerable <T> > GetMessagesAsync <T>(string request, Func <byte[], int, MessageContainer <T> > messageHandler)
{
var client = await _lookupDispatcher.TakeAsync();
var messages = new List <T>();
var invalidMessages = new List <InvalidMessage <T> >();
var ct = new CancellationTokenSource(_timeout);
var res = new TaskCompletionSource <IEnumerable <T> >();
ct.Token.Register(() => res.TrySetCanceled(), false);
void SocketClientOnMessageReceived(object sender, SocketMessageEventArgs args)
{
var container = messageHandler(args.Message, args.Count);
// exception must be throw at the very end when all messages have been received and parsed to avoid
// continuation in the next request since we don't use request id
if (container.ErrorMessage != null)
{
res.TrySetException(_exceptionFactory.CreateNew(request, container.ErrorMessage, container.MessageTrace));
return;
}
messages.AddRange(container.Messages);
invalidMessages.AddRange(container.InvalidMessages);
if (!container.End)
{
return;
}
if (invalidMessages.Count > 0)
{
res.TrySetException(_exceptionFactory.CreateNew(request, invalidMessages, messages));
return;
}
res.TrySetResult(messages);
}
client.MessageReceived += SocketClientOnMessageReceived;
await _lookupRateLimiter.WaitAsync().ConfigureAwait(false);
client.Send(request);
await res.Task.ContinueWith(x =>
{
client.MessageReceived -= SocketClientOnMessageReceived;
_lookupDispatcher.Add(client);
ct.Dispose();
}, TaskContinuationOptions.None).ConfigureAwait(false);
return(await res.Task.ConfigureAwait(false));
}
public async Task Should_Rate_Limit_By_Throughput()
{
// Arrange
var totalSeconds = TimeSpan.FromSeconds(15).TotalSeconds;
var seconds = 0;
var requestsPerSecond = 50;
var requestsCount = 0;
var requests = new List <int>();
var lookupRateLimiter = new LookupRateLimiter(requestsPerSecond);
var cts = new CancellationTokenSource();
// Act
_ = Task.Run(async() =>
{
while (true)
{
await lookupRateLimiter.WaitAsync();
Interlocked.Increment(ref requestsCount);
}
}, cts.Token);
while (seconds < totalSeconds)
{
var sw = Stopwatch.StartNew();
await Task.Delay(TimeSpan.FromSeconds(1));
sw.Stop();
Console.WriteLine($"requests: {requestsCount}/{sw.Elapsed.TotalMilliseconds}ms");
requests.Add(requestsCount);
Interlocked.Exchange(ref requestsCount, 0);
seconds++;
}
cts.Cancel();
cts.Dispose();
// Assert
Assert.That(requests.Average(), Is.EqualTo(requestsPerSecond).Within(2).Percent);
}
public async Task Should_Rate_Limit_By_Throughput()
{
// Arrange
var debug = false;
var totalSeconds = TimeSpan.FromSeconds(10).TotalSeconds;
var requestsPerSecond = 50;
var numberOfClients = 15;
var testResults = new List <TestResult>();
var lookupRateLimiter = new LookupRateLimiter(requestsPerSecond);
var cts = new CancellationTokenSource();
await Task.Delay(1000);
var tasks = new Task[numberOfClients];
var mutex = new object();
var requestsCount = 0;
var seconds = 0;
for (var i = 0; i < numberOfClients; i++)
{
var taskId = i;
tasks[i] = new Task(async() =>
{
while (true)
{
await lookupRateLimiter.WaitAsync().ConfigureAwait(false);
if (debug)
{
Console.WriteLine($"Executed task #{taskId}");
}
lock (mutex)
requestsCount++;
}
}, cts.Token);
}
// Act
for (var i = 0; i < numberOfClients; i++)
{
tasks[i].Start();
}
while (seconds < totalSeconds)
{
var sw = Stopwatch.StartNew();
await Task.Delay(TimeSpan.FromSeconds(1));
sw.Stop();
Console.WriteLine($"requests: {requestsCount}/{sw.Elapsed.TotalMilliseconds}ms");
lock (mutex)
{
testResults.Add(new TestResult(requestsCount, sw.Elapsed.TotalMilliseconds));
requestsCount = 0;
}
seconds++;
}
cts.Cancel();
cts.Dispose();
// Assert
// initial burst
var initialBurst = testResults.First();
var calcInitialBustRequestsPerSecond = initialBurst.NumberOfRequest * 1000 / initialBurst.TotalMilliseconds;
var expectedInitialBurst = lookupRateLimiter.RequestsPerSecond + lookupRateLimiter.MaxCount;
Assert.That(calcInitialBustRequestsPerSecond, Is.LessThan(expectedInitialBurst).Within(5).Percent);
Console.WriteLine($"Initial burst {calcInitialBustRequestsPerSecond} requests/second");
// average
var testResultsWithoutInitialBurst = testResults.Skip(1).ToList();
var totalMs = testResultsWithoutInitialBurst.Sum(x => x.TotalMilliseconds);
var totalRequests = testResultsWithoutInitialBurst.Sum(x => x.NumberOfRequest);
var calcRequestsPerSecond = totalRequests * 1000 / totalMs;
var variationPercentage = Math.Abs(calcRequestsPerSecond - requestsPerSecond) / requestsPerSecond * 100;
Console.WriteLine($"Average {calcRequestsPerSecond} requests/second");
Console.WriteLine($"Variation {variationPercentage} %");
Assert.That(calcRequestsPerSecond, Is.EqualTo(requestsPerSecond).Within(1).Percent);
}