public void MetricsChanged(ClusterMetricsChanged @event)
{
var oldValue = _weightedRouteesRef.Value;
var routees = oldValue.Item1;
var weightedRoutees = new WeightedRoutees(routees,
_cluster.SelfAddress,
_metricsSelector.Weights(@event.NodeMetrics).ToImmutableDictionary(pair => pair.Key, pair => pair.Value));
// retry when CAS failure
if (!_weightedRouteesRef.CompareAndSet(oldValue, Tuple.Create(routees, @event.NodeMetrics, weightedRoutees.AsOption())))
{
MetricsChanged(@event);
}
}
/// <inheritdoc />
public override Routee Select(object message, Routee[] routees)
{
if (routees.Length == 0)
{
return(Routee.NoRoutee);
}
Option <WeightedRoutees> UpdateWeightedRoutees()
{
var oldValue = _weightedRouteesRef.Value;
var(oldRoutees, oldMetrics, oldWeightedRoutees) = oldValue;
if (oldRoutees.Equals(routees.ToImmutableArray()))
{
return(oldWeightedRoutees);
}
var weightedRoutees = new WeightedRoutees(routees.ToImmutableArray(), _cluster.SelfAddress,
_metricsSelector.Weights(oldMetrics).ToImmutableDictionary(pair => pair.Key, pair => pair.Value));
// ignore, don't update, in case of CAS failure
_weightedRouteesRef.CompareAndSet(oldValue, Tuple.Create(routees.ToImmutableArray(), oldMetrics, weightedRoutees.AsOption()));
return(weightedRoutees);
}
var updated = UpdateWeightedRoutees();
if (updated.HasValue)
{
var weighted = updated.Value;
if (weighted.IsEmpty)
{
return(Routee.NoRoutee);
}
return(weighted[ThreadLocalRandom.Current.Next(weighted.Total) + 1]);
}
else
{
return(routees[ThreadLocalRandom.Current.Next(routees.Length)]);
}
}