public async Task Start(CancellationToken cancellationToken)
{
while (!cancellationToken.IsCancellationRequested)
{
try
{
var options = new EventHubProducerClientOptions
{
RetryOptions = new EventHubsRetryOptions
{
TryTimeout = Configuration.SendTimeout
}
};
var producer = new EventHubProducerClient(Configuration.EventHubsConnectionString, Configuration.EventHub, options);
await using (producer.ConfigureAwait(false))
{
while (!cancellationToken.IsCancellationRequested)
{
// Query partitions each iteration to allow any new partitions to be discovered. Dynamic upscaling of partitions
// is a near-term feature being added to the Event Hubs service.
var partitions = await producer.GetPartitionIdsAsync(cancellationToken).ConfigureAwait(false);
var selectedPartition = partitions[RandomNumberGenerator.Value.Next(0, partitions.Length)];
var batchEvents = new List <EventData>();
// Create the batch and generate a set of random events, keeping only those that were able to fit into the batch.
using var batch = await producer.CreateBatchAsync(new CreateBatchOptions { PartitionId = selectedPartition }).ConfigureAwait(false);
var events = EventGenerator.CreateEvents(
Configuration.PublishBatchSize,
Configuration.LargeMessageRandomFactorPercent,
Configuration.PublishingBodyMinBytes,
Configuration.PublishingBodyRegularMaxBytes,
currentSequence,
selectedPartition);
foreach (var currentEvent in events)
{
if (!batch.TryAdd(currentEvent))
{
break;
}
batchEvents.Add(currentEvent);
}
// Publish the events and report them, capturing any failures specific to the send operation.
try
{
if (batch.Count > 0)
{
await producer.SendAsync(batch, cancellationToken).ConfigureAwait(false);
foreach (var batchEvent in batchEvents)
{
batchEvent.Properties.TryGetValue(EventGenerator.IdPropertyName, out var id);
PublishedEvents.AddOrUpdate(id.ToString(), _ => batchEvent, (k, v) => batchEvent);
}
Interlocked.Add(ref Metrics.EventsPublished, batch.Count);
Interlocked.Increment(ref Metrics.TotalServiceOperations);
}
}
catch (TaskCanceledException)
{
}
catch (EventHubsException ex)
{
Interlocked.Increment(ref Metrics.TotalExceptions);
Interlocked.Increment(ref Metrics.SendExceptions);
ex.TrackMetrics(Metrics);
ErrorsObserved.Add(ex);
}
catch (Exception ex)
{
Interlocked.Increment(ref Metrics.TotalExceptions);
Interlocked.Increment(ref Metrics.SendExceptions);
Interlocked.Increment(ref Metrics.GeneralExceptions);
ErrorsObserved.Add(ex);
}
// Honor any requested delays to throttle publishing so that it doesn't overwhelm slower consumers.
if ((Configuration.PublishingDelay.HasValue) && (Configuration.PublishingDelay.Value > TimeSpan.Zero))
{
await Task.Delay(Configuration.PublishingDelay.Value).ConfigureAwait(false);
}
}
}
}
catch (TaskCanceledException)
{
// No action needed.
}
catch (Exception ex) when
(ex is OutOfMemoryException ||
ex is StackOverflowException ||
ex is ThreadAbortException)
{
throw;
}
catch (Exception ex)
{
Interlocked.Increment(ref Metrics.ProducerRestarted);
ErrorsObserved.Add(ex);
}
}
}