public void LeastShardAllocationStrategy_should_allocate_to_region_with_least_number_of_shards()
{
var allocations = new Dictionary <IActorRef, IImmutableList <string> >
{
{ _regionA, new [] { "shard1" }.ToImmutableList() },
{ _regionB, new [] { "shard2" }.ToImmutableList() },
{ _regionC, ImmutableList <string> .Empty }
}.ToImmutableDictionary();
var result = _allocationStrategy.AllocateShard(_regionA, "shard3", allocations).Result;
Assert.Equal(result, _regionC);
}
private void HandleGetShardHome(GetShardHome getShardHome)
{
var shard = getShardHome.Shard;
if (_rebalanceInProgress.Contains(shard))
{
Log.Debug("GetShardHome [{0}] request ignored, because rebalance is in progress for this shard.", shard);
}
else if (!HasAllRegionsRegistered())
{
Log.Debug("GetShardHome [{0}] request ignored, because not all regions have registered yet.", shard);
}
else
{
if (_currentState.Shards.TryGetValue(shard, out var region))
{
if (_regionTerminationInProgress.Contains(region))
{
Log.Debug("GetShardHome [{0}] request ignored, due to region [{1}] termination in progress.", shard, region);
}
else
{
Sender.Tell(new ShardHome(shard, region));
}
}
else
{
var activeRegions = _currentState.Regions.RemoveRange(_gracefullShutdownInProgress);
if (activeRegions.Count != 0)
{
var getShardHomeSender = Sender;
var regionTask = AllocationStrategy.AllocateShard(getShardHomeSender, shard, activeRegions);
// if task completed immediately, just continue
if (regionTask.IsCompleted && !regionTask.IsFaulted)
{
ContinueGetShardHome(shard, regionTask.Result, getShardHomeSender);
}
else
{
regionTask.ContinueWith(t => !(t.IsFaulted || t.IsCanceled)
? new AllocateShardResult(shard, t.Result, getShardHomeSender)
: new AllocateShardResult(shard, null, getShardHomeSender), TaskContinuationOptions.ExecuteSynchronously)
.PipeTo(Self);
}
}
}
}
}
internal static IImmutableDictionary <IActorRef, IImmutableList <string> > AfterRebalance(
IShardAllocationStrategy allocationStrategy,
IImmutableDictionary <IActorRef, IImmutableList <string> > allocations,
IImmutableSet <string> rebalance)
{
var allocationsAfterRemoval = allocations.SetItems(allocations.Select(i => new KeyValuePair <IActorRef, IImmutableList <string> >(i.Key, i.Value.ToImmutableHashSet().Except(rebalance).OrderBy(j => j).ToImmutableList())));
IImmutableDictionary <IActorRef, IImmutableList <string> > acc = allocationsAfterRemoval;
foreach (var shard in rebalance.OrderBy(i => i))
{
var region = allocationStrategy.AllocateShard(new DummyActorRef(), shard, acc).Result;
acc = acc.SetItem(region, acc[region].Add(shard));
}
return(acc);
}