public async Task <BecomeCoordinatorResult> BecomeCoordinatorAsync(int currentEpoch)
{
try
{
this.ignoreWatches = false;
await this.zooKeeperService.IncrementAndWatchEpochAsync(currentEpoch, this);
await this.zooKeeperService.WatchNodesAsync(this);
var getResourcesRes = await this.zooKeeperService.GetResourcesAsync(this, null);
this.resourcesVersion = getResourcesRes.Version;
this.status = await this.zooKeeperService.GetStatusAsync();
}
catch (ZkStaleVersionException e)
{
this.logger.Error(this.clientId, "Could not become coordinator as a stale version number was used", e);
return(BecomeCoordinatorResult.StaleEpoch);
}
catch (ZkInvalidOperationException e)
{
this.logger.Error(this.clientId, "Could not become coordinator as an invalid ZooKeeper operation occurred", e);
return(BecomeCoordinatorResult.Error);
}
this.events.Add(CoordinatorEvent.RebalancingTriggered);
return(BecomeCoordinatorResult.Ok);
}
private async Task SendTriggerRebalancingEvent()
{
try
{
StatusZnode status = await zooKeeperService.WatchStatusAsync(this);
statusVersion = status.Version;
events.Add(FollowerEvent.RebalancingTriggered);
}
catch (Exception e)
{
logger.Error("Follower - Could not put a watch on the status node", e);
events.Add(FollowerEvent.PotentialInconsistentState);
}
}
private async Task <RebalancingResult> ProcessStatusChangeAsync(CancellationToken rebalancingToken)
{
StatusZnode status = await zooKeeperService.WatchStatusAsync(this);
if (status.Version != statusVersion)
{
logger.Warn(clientId, "Follower - The status has changed between the notification and response");
}
if (rebalancingToken.IsCancellationRequested)
{
return(RebalancingResult.Cancelled);
}
if (status.RebalancingStatus == RebalancingStatus.StopActivity)
{
logger.Info(clientId, "Follower - Status change received - stop activity");
await store.InvokeOnStopActionsAsync(clientId, "Follower");
if (rebalancingToken.IsCancellationRequested)
{
return(RebalancingResult.Cancelled);
}
await zooKeeperService.SetFollowerAsStopped(clientId);
logger.Info(clientId, "Follower - Created follower stopped node");
}
else if (status.RebalancingStatus == RebalancingStatus.ResourcesGranted)
{
logger.Info(clientId, "Follower - Status change received - resources granted");
ResourcesZnode resources = await zooKeeperService.GetResourcesAsync(null, null);
List <string> assignedResources = resources.ResourceAssignments.Assignments
.Where(x => x.ClientId.Equals(clientId))
.Select(x => x.Resource)
.ToList();
logger.Info(clientId, $"Follower - {assignedResources.Count} resources granted");
if (store.IsInStartedState())
{
logger.Warn(clientId,
"Follower - The resources granted status change has been received while already in the started state. Stopped all activity first");
await store.InvokeOnStopActionsAsync(clientId, "Follower");
}
if (onStartDelay.Ticks > 0)
{
logger.Info(clientId, $"Follower - Delaying on start for {(int)onStartDelay.TotalMilliseconds}ms");
await WaitFor(onStartDelay, rebalancingToken);
}
if (rebalancingToken.IsCancellationRequested)
{
return(RebalancingResult.Cancelled);
}
await store.InvokeOnStartActionsAsync(clientId, "Follower", assignedResources, rebalancingToken,
followerToken);
if (rebalancingToken.IsCancellationRequested)
{
return(RebalancingResult.Cancelled);
}
await zooKeeperService.SetFollowerAsStarted(clientId);
logger.Info(clientId, "Follower - Removed follower stopped node");
}
else if (status.RebalancingStatus == RebalancingStatus.StartConfirmed)
{
logger.Info(clientId, "Follower - All followers confirm started"); // no longer used
}
else
{
logger.Error(clientId, "Follower - Non-supported status received - ignoring");
}
return(RebalancingResult.Complete);
}
