private async Task ResendExpiredMessagesAsync(CancellationToken cancellationToken)
{
while (!cancellationToken.IsCancellationRequested && _channel.IsEstablished())
{
try
{
await Task.Delay(_resendWindow, cancellationToken);
var expiredMessageKeys =
await _messageStorage.GetMessagesToResendKeysAsync(_channelKey, DateTimeOffset.UtcNow,
cancellationToken);
foreach (var expiredMessageKey in expiredMessageKeys)
{
cancellationToken.ThrowIfCancellationRequested();
var expiredMessage =
await _messageStorage.RemoveAsync(_channelKey, expiredMessageKey, cancellationToken);
if (expiredMessage == null)
{
continue; // It may be already removed
}
var resendCount = GetMessageResendCount(expiredMessage);
// Check the message resend limit
if (resendCount < _maxResendCount)
{
// Set the metadata key
resendCount++;
SetMessageResendCount(expiredMessage, resendCount);
try
{
await _channel.SendMessageAsync(expiredMessage, cancellationToken);
}
catch (Exception ex)
{
if (_resendExceptionHandler != null)
{
await _resendExceptionHandler(ex, _channel, expiredMessage);
}
else
{
Trace.TraceError(
"Error resending a message with id {0} on channel {1}: {2}",
expiredMessage.Id,
_channel.SessionId,
ex);
}
// Create a new CTS because the exception can be caused by the cancellation of the method token
using var cts = new CancellationTokenSource(TimeSpan.FromSeconds(5));
try
{
// If any error occurs when resending the message, put the expired message
// back into the storage before throwing the exception.
await _messageStorage.AddAsync(
_channelKey,
expiredMessageKey,
expiredMessage,
DateTimeOffset.UtcNow.Add(_resendWindow),
cts.Token);
}
catch (OperationCanceledException)
{
}
throw;
}
}
else
{
await _deadMessageHandler.HandleDeadMessageAsync(expiredMessage, _channel,
cancellationToken);
}
}
}
catch (ObjectDisposedException) when(_disposing)
{
break;
}
catch (OperationCanceledException) when(cancellationToken.IsCancellationRequested)
{
break;
}
catch (Exception ex)
{
if (_resendExceptionHandler != null)
{
await _resendExceptionHandler(ex, _channel, null);
}
else
{
Trace.TraceError(
"An unhandled exception occurred on ResendMessagesChannelModule on channel {0}: {1}",
_channel.SessionId,
ex);
}
}
}
}
private async Task ResendExpiredMessagesAsync(CancellationToken cancellationToken)
{
while (!cancellationToken.IsCancellationRequested && _channel.State == SessionState.Established && _channel.Transport.IsConnected)
{
try
{
await Task.Delay(_resendWindow, cancellationToken);
var expiredMessageKeys =
await _messageStorage.GetMessagesToResendKeysAsync(_channelKey, DateTimeOffset.UtcNow, cancellationToken);
foreach (var expiredMessageKey in expiredMessageKeys)
{
cancellationToken.ThrowIfCancellationRequested();
var expiredMessage = await _messageStorage.RemoveAsync(_channelKey, expiredMessageKey, cancellationToken);
if (expiredMessage == null)
{
continue; // It may be already removed
}
var resendCount = GetMessageResendCount(expiredMessage);
// Check the message resend limit
if (resendCount < _maxResendCount)
{
// Set the metadata key
resendCount++;
SetMessageResendCount(expiredMessage, resendCount);
try
{
await _channel.SendMessageAsync(expiredMessage, cancellationToken);
}
catch
{
// Create a new CTS because the exception can be caused by the cancellation of the method token
using (var cts = new CancellationTokenSource(TimeSpan.FromSeconds(5)))
{
try
{
// If any error occurs when resending the message, put the expired message
// back into the storage before throwing the exception.
await _messageStorage.AddAsync(_channelKey, expiredMessageKey, expiredMessage,
DateTimeOffset.UtcNow, cts.Token);
}
catch (OperationCanceledException) { }
throw;
}
}
}
else
{
await _deadMessageHandler.HandleDeadMessageAsync(expiredMessage, _channel, cancellationToken);
}
}
}
catch (OperationCanceledException) when(cancellationToken.IsCancellationRequested)
{
break;
}
catch (Exception ex)
{
Trace.TraceError(ex.ToString());
if (_channel.State != SessionState.Established || !_channel.Transport.IsConnected)
{
break;
}
throw;
}
}
}
