[英]Restricting SendAsync calls to 5 messages per second
我正在實施 Binance 的 API。
文檔說:
WebSocket 連接每秒有 5 條傳入消息的限制。 一條消息被認為是:
- 一個 PING 幀
- 一個 PONG 框架
- JSON 控制的消息(例如訂閱、取消訂閱)
例如。 有一個簡單的網絡套接字包裝器,例如來自官方Binance Connector的包裝器。 根據上面的限制, SendAsync
應該限制為每秒 5 條消息。 如果幾個線程同時調用SendAsync 5次(包括ClientWebSocket類內置的PING幀),就會失敗。 我怎樣才能優雅地解決這個限制的問題? 使用有界通道是一種解決方案嗎?
public class BinanceWebSocket : IDisposable
{
private IBinanceWebSocketHandler handler;
private List<Func<string, Task>> onMessageReceivedFunctions;
private List<CancellationTokenRegistration> onMessageReceivedCancellationTokenRegistrations;
private CancellationTokenSource loopCancellationTokenSource;
private Uri url;
private int receiveBufferSize;
public BinanceWebSocket(IBinanceWebSocketHandler handler, string url, int receiveBufferSize = 8192)
{
this.handler = handler;
this.url = new Uri(url);
this.receiveBufferSize = receiveBufferSize;
this.onMessageReceivedFunctions = new List<Func<string, Task>>();
this.onMessageReceivedCancellationTokenRegistrations = new List<CancellationTokenRegistration>();
}
public async Task ConnectAsync(CancellationToken cancellationToken)
{
if (this.handler.State != WebSocketState.Open)
{
this.loopCancellationTokenSource = CancellationTokenSource.CreateLinkedTokenSource(cancellationToken);
await this.handler.ConnectAsync(this.url, cancellationToken);
await Task.Factory.StartNew(() => this.ReceiveLoop(loopCancellationTokenSource.Token, this.receiveBufferSize), loopCancellationTokenSource.Token, TaskCreationOptions.LongRunning, TaskScheduler.Default);
}
}
public async Task DisconnectAsync(CancellationToken cancellationToken)
{
if (this.loopCancellationTokenSource != null)
{
this.loopCancellationTokenSource.Cancel();
}
if (this.handler.State == WebSocketState.Open)
{
await this.handler.CloseOutputAsync(WebSocketCloseStatus.NormalClosure, null, cancellationToken);
await this.handler.CloseAsync(WebSocketCloseStatus.NormalClosure, null, cancellationToken);
}
}
public void OnMessageReceived(Func<string, Task> onMessageReceived, CancellationToken cancellationToken)
{
this.onMessageReceivedFunctions.Add(onMessageReceived);
if (cancellationToken != CancellationToken.None)
{
var reg = cancellationToken.Register(() =>
this.onMessageReceivedFunctions.Remove(onMessageReceived));
this.onMessageReceivedCancellationTokenRegistrations.Add(reg);
}
}
public async Task SendAsync(string message, CancellationToken cancellationToken)
{
byte[] byteArray = Encoding.ASCII.GetBytes(message);
await this.handler.SendAsync(new ArraySegment<byte>(byteArray), WebSocketMessageType.Text, true, cancellationToken);
}
public void Dispose()
{
this.DisconnectAsync(CancellationToken.None).Wait();
this.handler.Dispose();
this.onMessageReceivedCancellationTokenRegistrations.ForEach(ct => ct.Dispose());
this.loopCancellationTokenSource.Dispose();
}
private async Task ReceiveLoop(CancellationToken cancellationToken, int receiveBufferSize = 8192)
{
WebSocketReceiveResult receiveResult = null;
try
{
while (!cancellationToken.IsCancellationRequested)
{
var buffer = new ArraySegment<byte>(new byte[receiveBufferSize]);
receiveResult = await this.handler.ReceiveAsync(buffer, cancellationToken);
if (receiveResult.MessageType == WebSocketMessageType.Close)
{
break;
}
string content = Encoding.UTF8.GetString(buffer.ToArray());
this.onMessageReceivedFunctions.ForEach(omrf => omrf(content));
}
}
catch (TaskCanceledException)
{
await this.DisconnectAsync(CancellationToken.None);
}
}
}
SendAsync
正在使用 Channels 循環調用。 SingleReader
設置為 true,這意味着一次只有一個消費者。 從技術上講,它應該可以解決這個問題,但我不能 100% 確定,因為通道可能只會限制緩沖區中的數量。
private readonly Channel<string> _messagesTextToSendQueue = Channel.CreateUnbounded<string>(new UnboundedChannelOptions()
{
SingleReader = true,
SingleWriter = false
});
public ValueTask SendAsync(string message)
{
Validations.Validations.ValidateInput(message, nameof(message));
return _messagesTextToSendQueue.Writer.WriteAsync(message);
}
public void Send(string message)
{
Validations.Validations.ValidateInput(message, nameof(message));
_messagesTextToSendQueue.Writer.TryWrite(message);
}
private async Task SendTextFromQueue()
{
try
{
while (await _messagesTextToSendQueue.Reader.WaitToReadAsync())
{
while (_messagesTextToSendQueue.Reader.TryRead(out var message))
{
try
{
await SendInternalSynchronized(message).ConfigureAwait(false);
}
catch (Exception e)
{
Logger.Error(e, L($"Failed to send text message: '{message}'. Error: {e.Message}"));
}
}
}
}
catch (TaskCanceledException)
{
// task was canceled, ignore
}
catch (OperationCanceledException)
{
// operation was canceled, ignore
}
catch (Exception e)
{
if (_cancellationTotal.IsCancellationRequested || _disposing)
{
// disposing/canceling, do nothing and exit
return;
}
Logger.Trace(L($"Sending text thread failed, error: {e.Message}. Creating a new sending thread."));
StartBackgroundThreadForSendingText();
}
}
我會盡量保持簡單並使用Semaphore Slim來實現這一點,我創建了一個類來執行此任務。
public class ThrottlingLimiter
{
private readonly SemaphoreSlim _semaphore;
private readonly TimeSpan _timeUnit;
public ThrottlingLimiter(int maxActionsPerTimeUnit, TimeSpan timeUnit)
{
if (maxActionsPerTimeUnit < 1)
throw new ArgumentOutOfRangeException(nameof(maxActionsPerTimeUnit));
if (timeUnit < TimeSpan.Zero || timeUnit.TotalMilliseconds > int.MaxValue)
throw new ArgumentOutOfRangeException(nameof(timeUnit));
_semaphore = new SemaphoreSlim(maxActionsPerTimeUnit, maxActionsPerTimeUnit);
_timeUnit = timeUnit;
}
public async Task WaitAsync(CancellationToken cancellationToken = default)
{
await _semaphore.WaitAsync(cancellationToken).ConfigureAwait(false);
ScheduleSemaphoreRelease();
}
private async void ScheduleSemaphoreRelease()
{
await Task.Delay(_timeUnit).ConfigureAwait(false);
_semaphore.Release();
}
}
現在要使用這個類,你所要做的就是設置你的限制和時間跨度
public async Task SendData(List<string> allMessages)
{
// Limiting 5 calls per second
ThrottlingLimiter throttlingLimiter = new ThrottlingLimiter(5, TimeSpan.FromSeconds(1));
await Task.WhenAll(allMessages.Select(async message =>
{
await throttlingLimiter.WaitAsync();
try {
await SendInternalSynchronized(message);
// I am not sure what this SendInternalSynchronized returns but I would return some thing to keep a track if this call is successful or not
}
catch (Exception e)
{
Logger.Error(e, L($"Failed to send text message: {message}'. Error: {e.Message}"));
}
});
}
所以基本上這里會發生的是,無論你的列表有多大,ThrottlingLimiter 每秒只會發送 5 條消息,並等待下一秒發送接下來的 5 條消息。
所以,在你的情況下,從你的電話中獲取所有數據
await _messagesTextToSendQueue.Reader.WaitToReadAsync();
將其存儲到列表或任何集合中,並將其傳遞給 SendData 函數。
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