EvaluateShards()
{
// Get the send queue shard.
var sendShard = this.queueShardMonitor.SendShard;
if (sendShard == null)
{
var firstShardName = SlinqyQueueShard.GenerateFirstShardName(
this.queueShardMonitor.QueueName,
this.shardIndexPadding
);
await this.queueService
.CreateQueue(firstShardName)
.ConfigureAwait(false);
}
else
{
// Scale if needed.
if (sendShard.StorageUtilization > this.storageCapacityScaleOutThreshold)
{
await this.ScaleOut(sendShard).ConfigureAwait(false);
}
// Make sure shard states are set properly.
await this.SetShardStates()
.ConfigureAwait(
false);
}
// Finally queue it all to happen again!
await this.agentQueue
.Send(new EvaluateShardsCommand(), DateTimeOffset.UtcNow.AddSeconds(5))
.ConfigureAwait(false);
}
ScaleOut(
SlinqyQueueShard currentSendShard)
{
// Add next shard!
var nextShardName = SlinqyQueueShard.GenerateNextShardName(currentSendShard.PhysicalQueue.Name);
await this.queueService.CreateSendOnlyQueue(nextShardName)
.ConfigureAwait(false);
}
CreateQueueAsync(
string queueName,
int shardIndexPadding)
{
// TODO: Refactor - Much of this functionality overlaps with the Agent,
// let Agent create first shard too and remove this code.
if (string.IsNullOrWhiteSpace(queueName))
{
throw new ArgumentNullException(nameof(queueName));
}
var queueShardName = SlinqyQueueShard.GenerateFirstShardName(
slinqyQueueName: queueName,
shardIndexPadding: shardIndexPadding
);
// Call the function to create the first physical queue shard to establish the virtual queue.
// No need to do anything with the returned shard...
var shard = await this.physicalQueueService
.CreateQueue(queueShardName)
.ConfigureAwait(false);
var shardMonitor = new SlinqyQueueShardMonitor(
queueName,
this.physicalQueueService
);
await shardMonitor
.Start()
.ConfigureAwait(false);
var queue = new SlinqyQueue(
shardMonitor
);
this.slinqyQueues.TryAdd(queueName, queue);
return(queue);
}
ScaleOut(
SlinqyQueueShard currentSendShard)
{
// Add next shard!
var nextShardName = SlinqyQueueShard.GenerateNextShardName(currentSendShard.PhysicalQueue.Name);
await this.queueService.CreateSendOnlyQueue(nextShardName)
.ConfigureAwait(false);
}
