/// <summary>
/// Sends a set of events to the associated Event Hub using a batched approach.
/// </summary>
///
/// <param name="eventBatch">The event batch to send.</param>
/// <param name="cancellationToken">An optional <see cref="CancellationToken"/> instance to signal the request to cancel the operation.</param>
///
/// <returns>A task to be resolved on when the operation has completed.</returns>
///
/// <remarks>
/// The caller is assumed to retain ownership of the <paramref name="eventBatch" /> and
/// is responsible for managing its lifespan, including disposal.
/// </remarks>
///
public override async Task SendAsync(EventDataBatch eventBatch,
CancellationToken cancellationToken)
{
Argument.AssertNotNull(eventBatch, nameof(eventBatch));
Argument.AssertNotClosed(_closed, nameof(AmqpEventHubProducer));
AmqpMessage messageFactory() => MessageConverter.CreateBatchFromMessages(
eventBatch.AsEnumerable <AmqpMessage>(),
eventBatch.SendOptions?.PartitionKey);
await SendAsync(messageFactory, eventBatch.SendOptions?.PartitionKey, cancellationToken).ConfigureAwait(false);
}
/// <summary>
/// Sends an AMQP message that contains a batch of events to the associated Event Hub. If the size of events exceed the
/// maximum size of a single batch, an exception will be triggered and the send will fail.
/// </summary>
///
/// <param name="messages">The set of AMQP messages to packaged in a batch envelope and sent.</param>
/// <param name="partitionKey">The hashing key to use for influencing the partition to which events should be routed.</param>
/// <param name="cancellationToken">An optional <see cref="CancellationToken"/> instance to signal the request to cancel the operation.</param>
///
/// <remarks>
/// Callers retain ownership of the <paramref name="messages" /> passed and hold responsibility for
/// ensuring that they are disposed.
/// </remarks>
///
protected virtual async Task SendAsync(IReadOnlyCollection <AmqpMessage> messages,
string partitionKey,
CancellationToken cancellationToken)
{
var failedAttemptCount = 0;
var logPartition = PartitionId ?? partitionKey;
var operationId = Guid.NewGuid().ToString("D", CultureInfo.InvariantCulture);
TimeSpan? retryDelay;
SendingAmqpLink link;
try
{
var tryTimeout = RetryPolicy.CalculateTryTimeout(0);
while (!cancellationToken.IsCancellationRequested)
{
EventHubsEventSource.Log.EventPublishStart(EventHubName, logPartition, operationId);
try
{
using AmqpMessage batchMessage = MessageConverter.CreateBatchFromMessages(messages);
if (!SendLink.TryGetOpenedObject(out link))
{
link = await SendLink.GetOrCreateAsync(UseMinimum(ConnectionScope.SessionTimeout, tryTimeout), cancellationToken).ConfigureAwait(false);
}
// Validate that the batch of messages is not too large to send. This is done after the link is created to ensure
// that the maximum message size is known, as it is dictated by the service using the link.
if (batchMessage.SerializedMessageSize > MaximumMessageSize)
{
throw new EventHubsException(EventHubName, string.Format(CultureInfo.CurrentCulture, Resources.MessageSizeExceeded, operationId, batchMessage.SerializedMessageSize, MaximumMessageSize), EventHubsException.FailureReason.MessageSizeExceeded);
}
// Attempt to send the message batch.
var deliveryTag = new ArraySegment <byte>(BitConverter.GetBytes(Interlocked.Increment(ref _deliveryCount)));
var outcome = await link.SendMessageAsync(batchMessage, deliveryTag, AmqpConstants.NullBinary, cancellationToken).ConfigureAwait(false);
if (outcome.DescriptorCode != Accepted.Code)
{
throw AmqpError.CreateExceptionForError((outcome as Rejected)?.Error, EventHubName);
}
// The send operation should be considered successful; return to
// exit the retry loop.
return;
}
catch (Exception ex)
{
Exception activeEx = ex.TranslateServiceException(EventHubName);
// Determine if there should be a retry for the next attempt; if so enforce the delay but do not quit the loop.
// Otherwise, bubble the exception.
++failedAttemptCount;
retryDelay = RetryPolicy.CalculateRetryDelay(activeEx, failedAttemptCount);
if ((retryDelay.HasValue) && (!ConnectionScope.IsDisposed) && (!_closed) && (!cancellationToken.IsCancellationRequested))
{
EventHubsEventSource.Log.EventPublishError(EventHubName, logPartition, operationId, activeEx.Message);
await Task.Delay(retryDelay.Value, cancellationToken).ConfigureAwait(false);
tryTimeout = RetryPolicy.CalculateTryTimeout(failedAttemptCount);
}
else if (ex is AmqpException)
{
ExceptionDispatchInfo.Capture(activeEx).Throw();
}
else
{
throw;
}
}
}
// If no value has been returned nor exception thrown by this point,
// then cancellation has been requested.
throw new TaskCanceledException();
}
catch (TaskCanceledException)
{
throw;
}
catch (Exception ex)
{
EventHubsEventSource.Log.EventPublishError(EventHubName, logPartition, operationId, ex.Message);
throw;
}
finally
{
EventHubsEventSource.Log.EventPublishComplete(EventHubName, logPartition, operationId, failedAttemptCount);
}
}