public async Task RunLoadBalancingAsyncDoesNotStealOwnershipAsRecovery()
{
const int NumberOfPartitions = 8;
const int MinimumPartitionCount = 4;
const int OrphanedPartitionCount = 2;
var otherLoadBalancerIdentifier = Guid.NewGuid().ToString();
var partitionIds = Enumerable.Range(1, NumberOfPartitions).Select(p => p.ToString()).ToArray();
var storageManager = new InMemoryStorageManager((s) => Console.WriteLine(s));
var loadBalancer = new PartitionLoadBalancer(storageManager, Guid.NewGuid().ToString(), ConsumerGroup, FullyQualifiedNamespace, EventHubName, TimeSpan.FromMinutes(1), TimeSpan.FromSeconds(10));
// Ownership should start empty.
var completeOwnership = await storageManager.ListOwnershipAsync(FullyQualifiedNamespace, EventHubName, ConsumerGroup);
Assert.That(completeOwnership.Count(), Is.EqualTo(0), "Storage should be tracking no ownership to start.");
Assert.That(loadBalancer.OwnedPartitionIds.Count(), Is.EqualTo(0), "The load balancer should start with no ownership.");
// Claim the minimum set of partitions for the "other" load balancer.
completeOwnership = await storageManager.ClaimOwnershipAsync(CreatePartitionOwnership(partitionIds.Take(MinimumPartitionCount), otherLoadBalancerIdentifier));
Assert.That(completeOwnership.Count(), Is.EqualTo(MinimumPartitionCount), "Storage should be tracking half the partitions as owned by another processor.");
Assert.That(loadBalancer.OwnedPartitionIds.Count(), Is.EqualTo(0), "The load balancer should have no ownership of any partitions.");
// Mimic the state of a processor when recovering from a crash; storage says that the processor has ownership of some
// number of partitions, but the processor state does not reflect that ownership.
//
// Assign the processor ownership over half of the partitions in storage, but do not formally claim them.
await storageManager.ClaimOwnershipAsync(CreatePartitionOwnership( partitionIds.Skip(MinimumPartitionCount).Take(OrphanedPartitionCount), loadBalancer.OwnerIdentifier));
completeOwnership = await storageManager.ListOwnershipAsync(FullyQualifiedNamespace, EventHubName, ConsumerGroup);
Assert.That(completeOwnership.Count(), Is.EqualTo(OrphanedPartitionCount + MinimumPartitionCount), "Storage should be tracking half the partitions as owned by another processor as well as some orphans.");
Assert.That(loadBalancer.OwnedPartitionIds.Count(), Is.EqualTo(0), "The load balancer should have no ownership of orphaned or otherwise owned partitions.");
// Run one load balancing cycle. At the end of the cycle, it should have claimed a random partition
// and recovered ownership of the orphans.
await loadBalancer.RunLoadBalancingAsync(partitionIds, CancellationToken.None);
completeOwnership = await storageManager.ListOwnershipAsync(FullyQualifiedNamespace, EventHubName, ConsumerGroup);
Assert.That(completeOwnership.Count(), Is.EqualTo(OrphanedPartitionCount + MinimumPartitionCount + 1), "Storage should be tracking the orphaned partitions, other processor partitions, and one additional as owned.");
Assert.That(loadBalancer.OwnedPartitionIds.Count(), Is.EqualTo(OrphanedPartitionCount + 1), "The load balancer should have ownership of all orphaned partitions and one additional.");
// Run load balancing cycles until the load balancer believes that the state is balanced or the partition count is quadrupled.
var cycleCount = 0;
while ((!loadBalancer.IsBalanced) && (cycleCount < (NumberOfPartitions * 4)))
{
await loadBalancer.RunLoadBalancingAsync(partitionIds, CancellationToken.None);
++cycleCount;
}
// All partitions should be owned by load balancer.
completeOwnership = await storageManager.ListOwnershipAsync(FullyQualifiedNamespace, EventHubName, ConsumerGroup);
Assert.That(completeOwnership.Count(), Is.EqualTo(NumberOfPartitions));
}
public async Task RunLoadBalancingAsyncStealsPartitionsWhenThisLoadbalancerOwnsLessThanMinPartitionsAndOtherLoadbalancerOwnsMaxPartitions()
{
const int MinimumpartitionCount = 4;
const int MaximumpartitionCount = 5;
const int NumberOfPartitions = 12;
var partitionIds = Enumerable.Range(1, NumberOfPartitions).Select(p => p.ToString()).ToArray();
var storageManager = new InMemoryStorageManager((s) => Console.WriteLine(s));
var loadbalancer = new PartitionLoadBalancer(
storageManager, Guid.NewGuid().ToString(), ConsumerGroup, FullyQualifiedNamespace, EventHubName, TimeSpan.FromMinutes(1), TimeSpan.FromSeconds(10));
// Create more partitions owned by this load balancer.
var loadbalancer1PartitionIds = Enumerable.Range(1, MinimumpartitionCount - 1);
var completeOwnership = CreatePartitionOwnership(loadbalancer1PartitionIds.Select(i => i.ToString()), loadbalancer.OwnerIdentifier);
// Create more partitions owned by a different load balancer.
var loadbalancer2Id = Guid.NewGuid().ToString();
var loadbalancer2PartitionIds = Enumerable.Range(loadbalancer1PartitionIds.Max() + 1, MinimumpartitionCount);
completeOwnership = completeOwnership
.Concat(CreatePartitionOwnership(loadbalancer2PartitionIds.Select(i => i.ToString()), loadbalancer2Id));
// Create more partitions owned by a different load balancer above the MaximumPartitionCount.
var loadbalancer3Id = Guid.NewGuid().ToString();
var stealablePartitionIds = Enumerable.Range(loadbalancer2PartitionIds.Max() + 1, MaximumpartitionCount);
completeOwnership = completeOwnership
.Concat(CreatePartitionOwnership(stealablePartitionIds.Select(i => i.ToString()), loadbalancer3Id));
// Seed the storageManager with the owned partitions.
await storageManager.ClaimOwnershipAsync(completeOwnership);
// Get owned partitions.
var totalOwnedPartitions = await storageManager.ListOwnershipAsync(loadbalancer.FullyQualifiedNamespace, loadbalancer.EventHubName, loadbalancer.ConsumerGroup);
var ownedByloadbalancer1 = totalOwnedPartitions.Where(p => p.OwnerIdentifier == loadbalancer.OwnerIdentifier);
var ownedByloadbalancer3 = totalOwnedPartitions.Where(p => p.OwnerIdentifier == loadbalancer3Id);
// Verify owned partitionIds match the owned partitions.
Assert.That(ownedByloadbalancer1.Any(owned => stealablePartitionIds.Contains(int.Parse(owned.PartitionId))), Is.False);
// Verify load balancer 3 has stealable partitions.
Assert.That(ownedByloadbalancer3.Count(), Is.EqualTo(MaximumpartitionCount));
// Start the load balancer to steal ownership from of a when ownedPartitionCount == MinimumOwnedPartitionsCount but a load balancer owns > MaximumPartitionCount.
await loadbalancer.RunLoadBalancingAsync(partitionIds, CancellationToken.None);
// Get owned partitions.
totalOwnedPartitions = await storageManager.ListOwnershipAsync(loadbalancer.FullyQualifiedNamespace, loadbalancer.EventHubName, loadbalancer.ConsumerGroup);
ownedByloadbalancer1 = totalOwnedPartitions.Where(p => p.OwnerIdentifier == loadbalancer.OwnerIdentifier);
ownedByloadbalancer3 = totalOwnedPartitions.Where(p => p.OwnerIdentifier == loadbalancer3Id);
// Verify that we took ownership of the additional partition.
Assert.That(ownedByloadbalancer1.Any(owned => stealablePartitionIds.Contains(int.Parse(owned.PartitionId))), Is.True);
// Verify load balancer 3 now does not own > MaximumPartitionCount.
Assert.That(ownedByloadbalancer3.Count(), Is.LessThan(MaximumpartitionCount));
}
public async Task ProcessorClientBeginsWithTheNextEventAfterCheckpointing()
{
// Setup the environment.
await using EventHubScope scope = await EventHubScope.CreateAsync(1);
var connectionString = TestEnvironment.BuildConnectionStringForEventHub(scope.EventHubName);
using var cancellationSource = new CancellationTokenSource();
cancellationSource.CancelAfter(TimeSpan.FromMinutes(4));
// Send a set of events.
var segmentEventCount = 25;
var beforeCheckpointEvents = CreateEvents(segmentEventCount).ToList();
var afterCheckpointEvents = CreateEvents(segmentEventCount, segmentEventCount).ToList();
var sourceEvents = Enumerable.Concat(beforeCheckpointEvents, afterCheckpointEvents).ToList();
var checkpointEvent = beforeCheckpointEvents.Last();
var sentCount = await SendEvents(connectionString, sourceEvents, cancellationSource.Token);
Assert.That(sentCount, Is.EqualTo(sourceEvents.Count), "Not all of the source events were sent.");
// Attempt to read back the first half of the events and checkpoint.
Func <ProcessEventArgs, Task> processedEventCallback = async args =>
{
if (args.Data.IsEquivalentTo(checkpointEvent))
{
await args.UpdateCheckpointAsync(cancellationSource.Token);
}
};
var processedEvents = new ConcurrentDictionary <string, EventData>();
var completionSource = new TaskCompletionSource <bool>(TaskCreationOptions.RunContinuationsAsynchronously);
var beforeCheckpointProcessHandler = CreateEventTrackingHandler(segmentEventCount, processedEvents, completionSource, cancellationSource.Token, processedEventCallback);
var options = new EventProcessorOptions {
LoadBalancingUpdateInterval = TimeSpan.FromMilliseconds(250)
};
var storageManager = new InMemoryStorageManager(_ => {});
var processor = CreateProcessor(scope.ConsumerGroups.First(), connectionString, storageManager, options);
processor.ProcessErrorAsync += CreateAssertingErrorHandler();
processor.ProcessEventAsync += beforeCheckpointProcessHandler;
await processor.StartProcessingAsync(cancellationSource.Token);
await Task.WhenAny(completionSource.Task, Task.Delay(Timeout.Infinite, cancellationSource.Token));
Assert.That(cancellationSource.IsCancellationRequested, Is.False, "The cancellation token should not have been signaled.");
await processor.StopProcessingAsync(cancellationSource.Token);
// Validate a checkpoint was created and that events were processed.
var checkpoints = (await storageManager.ListCheckpointsAsync(processor.FullyQualifiedNamespace, processor.EventHubName, processor.ConsumerGroup, cancellationSource.Token))?.ToList();
Assert.That(checkpoints, Is.Not.Null, "A checkpoint should have been created.");
Assert.That(checkpoints.Count, Is.EqualTo(1), "A single checkpoint should exist.");
Assert.That(processedEvents.Count, Is.AtLeast(beforeCheckpointEvents.Count), "All events before the checkpoint should have been processed.");
// Reset state and start the processor again; it should resume from the event following the checkpoint.
processedEvents.Clear();
completionSource = new TaskCompletionSource <bool>(TaskCreationOptions.RunContinuationsAsynchronously);
processor.ProcessEventAsync -= beforeCheckpointProcessHandler;
processor.ProcessEventAsync += CreateEventTrackingHandler(segmentEventCount, processedEvents, completionSource, cancellationSource.Token);
await processor.StartProcessingAsync(cancellationSource.Token);
await Task.WhenAny(completionSource.Task, Task.Delay(Timeout.Infinite, cancellationSource.Token));
Assert.That(cancellationSource.IsCancellationRequested, Is.False, "The cancellation token should not have been signaled.");
await processor.StopProcessingAsync(cancellationSource.Token);
cancellationSource.Cancel();
foreach (var sourceEvent in afterCheckpointEvents)
{
var sourceId = sourceEvent.Properties[CustomIdProperty].ToString();
Assert.That(processedEvents.TryGetValue(sourceId, out var processedEvent), Is.True, $"The event with custom identifier [{ sourceId }] was not processed.");
Assert.That(sourceEvent.IsEquivalentTo(processedEvent), $"The event with custom identifier [{ sourceId }] did not match the corresponding processed event.");
}
}
public async Task RunLoadBalancingAsyncClaimsPartitionsWhenOwnedEqualsMinimumOwnedPartitionsCount()
{
const int MinimumPartitionCount = 4;
const int NumberOfPartitions = 13;
var partitionIds = Enumerable.Range(1, NumberOfPartitions).Select(p => p.ToString()).ToArray();
var storageManager = new InMemoryStorageManager((s) => Console.WriteLine(s));
var loadbalancer = new PartitionLoadBalancer(
storageManager, Guid.NewGuid().ToString(), ConsumerGroup, FullyQualifiedNamespace, EventHubName, TimeSpan.FromMinutes(1), TimeSpan.FromSeconds(10));
// Create partitions owned by this load balancer.
var loadbalancer1PartitionIds = Enumerable.Range(1, MinimumPartitionCount);
var completeOwnership = CreatePartitionOwnership(loadbalancer1PartitionIds.Select(i => i.ToString()), loadbalancer.OwnerIdentifier);
// Create partitions owned by a different load balancer.
var loadbalancer2Id = Guid.NewGuid().ToString();
var loadbalancer2PartitionIds = Enumerable.Range(loadbalancer1PartitionIds.Max() + 1, MinimumPartitionCount);
completeOwnership = completeOwnership
.Concat(CreatePartitionOwnership(loadbalancer2PartitionIds.Select(i => i.ToString()), loadbalancer2Id));
// Create partitions owned by a different load balancer.
var loadbalancer3Id = Guid.NewGuid().ToString();
var loadbalancer3PartitionIds = Enumerable.Range(loadbalancer2PartitionIds.Max() + 1, MinimumPartitionCount);
completeOwnership = completeOwnership
.Concat(CreatePartitionOwnership(loadbalancer3PartitionIds.Select(i => i.ToString()), loadbalancer3Id));
// Seed the storageManager with all partitions.
await storageManager.ClaimOwnershipAsync(completeOwnership);
var claimablePartitionIds = partitionIds.Except(completeOwnership.Select(p => p.PartitionId));
// Get owned partitions.
var totalOwnedPartitions = await storageManager.ListOwnershipAsync(loadbalancer.FullyQualifiedNamespace, loadbalancer.EventHubName, loadbalancer.ConsumerGroup);
var ownedByloadbalancer1 = totalOwnedPartitions.Where(p => p.OwnerIdentifier == loadbalancer.OwnerIdentifier);
// Verify owned partitionIds match the owned partitions.
Assert.That(ownedByloadbalancer1.Count(), Is.EqualTo(MinimumPartitionCount));
Assert.That(ownedByloadbalancer1.Any(owned => claimablePartitionIds.Contains(owned.PartitionId)), Is.False);
// Start the load balancer to claim ownership from of a Partition even though ownedPartitionCount == MinimumOwnedPartitionsCount.
await loadbalancer.RunLoadBalancingAsync(partitionIds, CancellationToken.None);
// Get owned partitions.
totalOwnedPartitions = await storageManager.ListOwnershipAsync(loadbalancer.FullyQualifiedNamespace, loadbalancer.EventHubName, loadbalancer.ConsumerGroup);
ownedByloadbalancer1 = totalOwnedPartitions.Where(p => p.OwnerIdentifier == loadbalancer.OwnerIdentifier);
// Verify that we took ownership of the additional partition.
Assert.That(ownedByloadbalancer1.Count(), Is.GreaterThan(MinimumPartitionCount));
Assert.That(ownedByloadbalancer1.Any(owned => claimablePartitionIds.Contains(owned.PartitionId)), Is.True);
}
public async Task ProcessorClientCreatesOwnership()
{
// Setup the environment.
var partitionCount = 2;
var partitionIds = new HashSet <string>();
await using EventHubScope scope = await EventHubScope.CreateAsync(partitionCount);
var connectionString = TestEnvironment.BuildConnectionStringForEventHub(scope.EventHubName);
using var cancellationSource = new CancellationTokenSource();
cancellationSource.CancelAfter(TimeSpan.FromMinutes(2));
// Discover the partitions.
await using (var producer = new EventHubProducerClient(connectionString))
{
foreach (var partitionId in (await producer.GetPartitionIdsAsync()))
{
partitionIds.Add(partitionId);
}
}
// Send a set of events.
var sourceEvents = CreateEvents(200).ToList();
var sentCount = await SendEvents(connectionString, sourceEvents, cancellationSource.Token);
Assert.That(sentCount, Is.EqualTo(sourceEvents.Count), "Not all of the source events were sent.");
// Attempt to read back the events.
var processedEvents = new ConcurrentDictionary <string, EventData>();
var completionSource = new TaskCompletionSource <bool>(TaskCreationOptions.RunContinuationsAsynchronously);
var storageManager = new InMemoryStorageManager(_ => {});
var options = new EventProcessorOptions {
LoadBalancingUpdateInterval = TimeSpan.FromMilliseconds(250)
};
var processor = CreateProcessorWithIdentity(scope.ConsumerGroups.First(), scope.EventHubName, storageManager, options);
processor.ProcessErrorAsync += CreateAssertingErrorHandler();
processor.ProcessEventAsync += CreateEventTrackingHandler(sentCount, processedEvents, completionSource, cancellationSource.Token);
await processor.StartProcessingAsync(cancellationSource.Token);
await Task.WhenAny(completionSource.Task, Task.Delay(Timeout.Infinite, cancellationSource.Token));
Assert.That(cancellationSource.IsCancellationRequested, Is.False, $"The cancellation token should not have been signaled. { processedEvents.Count } events were processed.");
await processor.StopProcessingAsync(cancellationSource.Token);
cancellationSource.Cancel();
// Validate that events that were processed.
var ownership = (await storageManager.ListOwnershipAsync(TestEnvironment.FullyQualifiedNamespace, scope.EventHubName, scope.ConsumerGroups.First(), cancellationSource.Token))?.ToList();
Assert.That(ownership, Is.Not.Null, "The ownership list should have been returned.");
Assert.That(ownership.Count, Is.AtLeast(1), "At least one partition should have been owned.");
foreach (var partitionOwnership in ownership)
{
Assert.That(partitionIds.Contains(partitionOwnership.PartitionId), Is.True, $"The partition `{ partitionOwnership.PartitionId }` is not valid for the Event Hub.");
Assert.That(partitionOwnership.OwnerIdentifier, Is.Empty, "Ownership should have bee relinquished when the processor was stopped.");
}
}