/// <summary>
/// Attempts to obtain a connection to the provided <paramref name="validHost"/> and send the request with it.
/// If no connection could be obtained for the provided host, then attempts to obtain a connection
/// for the next host, following the query plan.
/// </summary>
/// <param name="validHost">First host to which the method tries to obtain a connection.</param>
/// <returns></returns>
private async Task SendToNextHostAsync(ValidHost validHost)
{
try
{
IConnection connection = null;
while (connection == null)
{
connection = await _parent.GetConnectionToValidHostAsync(validHost, _triedHosts).ConfigureAwait(false);
if (connection == null)
{
validHost = _parent.GetNextValidHost(_triedHosts);
}
}
_connection = connection;
_host = validHost.Host;
Send(_request, validHost.Host, HandleResponse);
}
catch (Exception ex)
{
_host = validHost.Host;
HandleResponse(RequestError.CreateClientError(ex, true), null, validHost.Host);
}
}
/// <summary>
/// Useful method to retry the execution safely. While <see cref="Start"/> throws exceptions,
/// this method catches them and marks the <see cref="_parent"/> request as complete,
/// making it suitable to be called in a fire and forget manner.
/// </summary>
private void RetryExecution(bool currentHostRetry, Host host)
{
try
{
Start(currentHostRetry);
}
catch (Exception ex)
{
//There was an Exception before sending (probably no host is available).
//This will mark the Task as faulted.
HandleResponse(RequestError.CreateClientError(ex, true), null, host);
}
}
/// <summary>
/// Marks this operation as timed-out, callbacks with the exception
/// and sets a handler when the response is received
/// </summary>
public bool MarkAsTimedOut(OperationTimedOutException ex, Action onReceive, long timestamp)
{
var previousState = Interlocked.CompareExchange(ref _state, StateTimedout, StateInit);
if (previousState != StateInit)
{
return(false);
}
//When the data is received, invoke on receive callback
var callback = Interlocked.Exchange(ref _callback, (_, __, ___) => onReceive());
Thread.MemoryBarrier();
_timeoutCallbackSet = true;
Task.Factory.StartNew(() => callback(RequestError.CreateClientError(ex, false), null, timestamp), CancellationToken.None, TaskCreationOptions.None, TaskScheduler.Default);
return(true);
}
internal static RetryDecision GetRetryDecisionFromClientError(Exception ex, IExtendedRetryPolicy policy, IStatement statement, Configuration config, int retryCount)
{
return(RequestExecution.GetRetryDecisionWithReason(RequestError.CreateClientError(ex, false), policy, statement, config, retryCount).Decision);
}