private void TestRebalance(
IShardAllocationStrategy allocationStrategy,
IImmutableDictionary <IActorRef, IImmutableList <string> > allocations,
ImmutableList <IImmutableDictionary <IActorRef, IImmutableList <string> > > steps,
int maxSteps)
{
var round = steps.Count;
var rebalanceResult = allocationStrategy.Rebalance(allocations, ImmutableHashSet <string> .Empty).Result;
var newAllocations = LeastShardAllocationStrategySpec.AfterRebalance(allocationStrategy, allocations, rebalanceResult);
LeastShardAllocationStrategySpec.CountShards(newAllocations).Should().Be(LeastShardAllocationStrategySpec.CountShards(allocations), $"test {allocationStrategy}[{ string.Join(", ", LeastShardAllocationStrategySpec.CountShardsPerRegion(allocations))}]: ");
var min = LeastShardAllocationStrategySpec.CountShardsPerRegion(newAllocations).Min();
var max = LeastShardAllocationStrategySpec.CountShardsPerRegion(newAllocations).Max();
var diff = max - min;
var newSteps = steps.Add(newAllocations);
if (diff <= 1)
{
if (round >= 3 && maxSteps <= 10)
{
// Should be very rare (I have not seen it)
Sys.Log.Info($"rebalance solved in round {round}, [{string.Join(" => ", newSteps.Select(step => string.Join(", ", LeastShardAllocationStrategySpec.CountShardsPerRegion(step))))}]");
}
}
else if (round == maxSteps)
{
throw new AssertionFailedException($"Couldn't solve rebalance in $round rounds, [{string.Join(" => ", newSteps.Select(step => string.Join(", ", LeastShardAllocationStrategySpec.CountShardsPerRegion(step))))}]");
}
else
{
TestRebalance(allocationStrategy, newAllocations, newSteps, maxSteps);
}
}
private void TestRebalance(
IShardAllocationStrategy allocationStrategy,
int maxRegions,
int maxShardsPerRegion,
int expectedMaxSteps)
{
foreach (var i in Enumerable.Range(1, iterationsPerTest))
{
iteration += 1;
var numberOfRegions = rnd.Next(maxRegions) + 1;
var memberArray = Enumerable.Range(1, numberOfRegions).Select(n => LeastShardAllocationStrategySpec.NewUpMember("127.0.0.1", port: n)).ToArray();
clusterMembers = ImmutableSortedSet.Create(memberArray);//.toIndexedSeq: _ *);
var regions = Enumerable.Range(1, numberOfRegions).Select(n => LeastShardAllocationStrategySpec.NewFakeRegion($"{iteration}-R{n}", memberArray[n - 1]));
//var regions = Enumerable.Range(1, numberOfRegions).Select(n => Sys.ActorOf(Props.Empty, $"{iteration}-R{n}")).ToImmutableList();
var countPerRegion = regions.ToImmutableDictionary(region => region, region => rnd.Next(maxShardsPerRegion));
var allocations = CreateAllocations(countPerRegion);
TestRebalance(allocationStrategy, allocations, ImmutableList.Create(allocations), expectedMaxSteps);
foreach (var region in regions)
{
Sys.Stop(region);
}
}
}
internal static IActorRef NewFakeRegion(string idForDebug, Member member) => LeastShardAllocationStrategySpec.NewFakeRegion(idForDebug, member);
internal static Member NewUpMember(string host, int port = 252525, AppVersion version = null) => LeastShardAllocationStrategySpec.NewUpMember(host, port, version);