private async Task <bool> SendPulsesOrHeartbeatToWebSocket(Task <WebSocketReceiveResult> receive, WebSocket webSocket,
LiveReplicationPulsesCollector collector, MemoryStream ms, int timeToWait)
{
if (receive.IsCompleted || webSocket.State != WebSocketState.Open)
{
return(false);
}
var tuple = await collector.Pulses.TryDequeueAsync(TimeSpan.FromMilliseconds(timeToWait));
if (tuple.Item1 == false)
{
await webSocket.SendAsync(WebSocketHelper.Heartbeat, WebSocketMessageType.Text, true, Database.DatabaseShutdown);
return(true);
}
ms.SetLength(0);
using (ContextPool.AllocateOperationContext(out JsonOperationContext context))
using (var writer = new BlittableJsonTextWriter(context, ms))
{
var pulse = tuple.Item2;
context.Write(writer, pulse.ToJson());
}
ms.TryGetBuffer(out ArraySegment <byte> bytes);
await webSocket.SendAsync(bytes, WebSocketMessageType.Text, true, Database.DatabaseShutdown);
return(true);
}
public async Task EnsureNoReplicationLoop(RavenServer server, string database)
{
var storage = await server.ServerStore.DatabasesLandlord.TryGetOrCreateResourceStore(database);
using (var collector = new LiveReplicationPulsesCollector(storage))
{
var etag1 = storage.DocumentsStorage.GenerateNextEtag();
await Task.Delay(3000);
var etag2 = storage.DocumentsStorage.GenerateNextEtag();
Assert.True(etag1 + 1 == etag2, "Replication loop found :(");
var groups = collector.Pulses.GetAll().GroupBy(p => p.Direction);
foreach (var group in groups)
{
var key = group.Key;
var count = group.Count();
Assert.True(count < 50, $"{key} seems to be excessive ({count})");
}
}
}
public async Task PulsesLive()
{
using (var webSocket = await HttpContext.WebSockets.AcceptWebSocketAsync())
{
var receiveBuffer = new ArraySegment <byte>(new byte[1024]);
var receive = webSocket.ReceiveAsync(receiveBuffer, Database.DatabaseShutdown);
using (var ms = new MemoryStream())
using (var collector = new LiveReplicationPulsesCollector(Database))
{
// 1. Send data to webSocket without making UI wait upon opening webSocket
await SendPulsesOrHeartbeatToWebSocket(receive, webSocket, collector, ms, 100);
// 2. Send data to webSocket when available
while (Database.DatabaseShutdown.IsCancellationRequested == false)
{
if (await SendPulsesOrHeartbeatToWebSocket(receive, webSocket, collector, ms, 4000) == false)
{
break;
}
}
}
}
}
