private async Task UnregisterChannels(WebSocket webSocket)
{
logger_.LogInformation("Unregistering websockets channels");
bool removedSocket = false;
int tries = 0;
logger_.LogInformation("Removing websocket");
while (!removedSocket && tries < MAX_CHANNEL_REMOVAL_TRIES)
{
removedSocket = subscriptions_.TryRemove(webSocket, out _);
if (!removedSocket)
{
++tries;
await Task.Delay(TimeSpan.FromSeconds(DICT_REMOVAL_HOLDOFF));
}
}
WebSocketStats.DecrementSubscriberCount();
logger_.LogDebug("WebSocket status " + webSocket.State);
logger_.LogInformation("Closing websocket");
if (WebSocketCanSend(webSocket))
{
await webSocket.CloseOutputAsync(WebSocketCloseStatus.EndpointUnavailable, "All subscriptions cancelled", CancellationToken.None);
logger_.LogInformation("Websocket closed");
}
logger_.LogInformation("Channel unregistered");
//TODO
// If the last subscriber is removed , clear the pending queue
}
private void RegisterChannel(WebSocket webSocket, string channelName)
{
if (subscriptions_.TryAdd(webSocket, new ConcurrentDictionary <string, byte>()))
{
WebSocketStats.IncrementSubscriberCount();
}
subscriptions_[webSocket].TryAdd(channelName, 1);
}
private async Task PublisherThread()
{
logger_.LogInformation("Initializing websocket publisher thread");
try
{
var keepRunning = true;
while (keepRunning)
{
//This call blocks on an empty queue
var message = await messageQueue_.DequeueAsync();
WebSocketStats.IncrementOutputMessages();
WebSocketStats.DecrementPendingQueueSize();
keepRunning = message.MessageType != BitprimWebSocketMessageType.SHUTDOWN;
if (keepRunning)
{
var buffer = Encoding.UTF8.GetBytes(message.Content);
foreach (var ws in subscriptions_)
{
if (ws.Value.TryGetValue(message.ChannelName, out var dummy))
{
try
{
await retryPolicy_.ExecuteAsync(async() =>
{
await ws.Key.SendAsync
(
new ArraySegment <byte>(buffer, 0, message.Content.Length),
WebSocketMessageType.Text,
true,
CancellationToken.None
);
WebSocketStats.IncrementSentMessages();
logger_.LogDebug($"Sent Frame {WebSocketMessageType.Text}: Len={message.Content.Length}, Fin={true}: {message.Content}");
});
}
catch (WebSocketException ex)
{
logger_.LogWarning(ex, "Maxed out retries sending to client, closing channels");
await UnregisterChannels(ws.Key);
}
}
}
}
}
}
catch (Exception ex)
{
logger_.LogError(ex, "PublisherThread error");
}
logger_.LogInformation("Closing websocket publisher thread");
}
private async Task Publish(string channelName, string item)
{
logger_.LogDebug($"Adding websocket message to queue ({channelName})");
if (subscriptions_.Count <= 0)
{
logger_.LogDebug("Zero subscriptions. websocket message dropped");
}
else
{
await messageQueue_.EnqueueAsync
(
new BitprimWebSocketMessage
{
ChannelName = channelName,
Content = item,
MessageType = BitprimWebSocketMessageType.PUBLICATION
}
);
WebSocketStats.IncrementInputMessages();
WebSocketStats.IncrementPendingQueueSize();
}
}
