public void ChangeRole(ReplicaRole newRole)
{
//// AppTrace.TraceMsg(TraceLogEventType.Information, "OperationFetcher.ChangeRole", "ChangeRole from {0} to {1}", this.role, newRole);
//// what are the state transistions possible?
ReplicaRole oldRole = this.role;
this.role = newRole;
if (oldRole == ReplicaRole.None && newRole == ReplicaRole.IdleSecondary)
{
if (this.drainQueuesInParallel)
{
OperationFetcher.DrainQueueAsyncHelper(this.copyOperationQueue);
OperationFetcher.DrainQueueAsyncHelper(this.replicationOperationQueue);
}
else
{
OperationFetcher.DrainQueueAsyncHelper(this.copyOperationQueue).ContinueWith(copyQueueDrainTask =>
{
//// AppTrace.TraceMsg(TraceLogEventType.Verbose, "OperationFetcher.QueueDrain", "Starting replication queue");
if (this.role == ReplicaRole.None)
{
//// AppTrace.TraceMsg(TraceLogEventType.Information, "OperationFetcher.QueueDrain", "ReplicaRole is None so not draining replication queue");
return;
}
OperationFetcher.DrainQueueAsyncHelper(this.replicationOperationQueue);
});
}
}
else if (oldRole == ReplicaRole.IdleSecondary && newRole == ReplicaRole.ActiveSecondary)
{
// No-Op
}
else if (oldRole == ReplicaRole.ActiveSecondary && newRole == ReplicaRole.Primary)
{
// No-Op
}
else if (oldRole == ReplicaRole.Primary && newRole == ReplicaRole.ActiveSecondary)
{
OperationFetcher.DrainQueueAsyncHelper(this.replicationOperationQueue);
}
else if (oldRole == ReplicaRole.None && newRole == ReplicaRole.Primary)
{
// No-op
}
else if (newRole == ReplicaRole.None)
{
// No-Op
}
else
{
// AppTrace.TraceMsg(TraceLogEventType.Error, "OperationFetcher.ChangeRole", "Invalid state change");
ReleaseAssert.Failfast(string.Format(CultureInfo.InvariantCulture, "Invalid State Change from {0} to {1}", oldRole, newRole));
}
}
public Instance(bool drainInParallel = false)
{
this.DrainInParallel = drainInParallel;
this.ReplicationQueue = new TQueue()
{
Name = "Replication"
};
this.CopyQueue = new TQueue()
{
Name = "Copy"
};
this.Fetcher = new OperationFetcher(this.CopyQueue, this.ReplicationQueue, this.DrainInParallel);
}
private static Task DrainQueueAsyncHelper(IOperationQueue queue)
{
return(queue.DrainAsync().ContinueWith(t => OperationFetcher.LogQueueDrainCompletion(t, queue.Name), TaskContinuationOptions.ExecuteSynchronously));
}