/// <summary>
/// The set of Akka.Cluster nodes designated for receiving heartbeats from this node.
/// </summary>
/// <param name="sender">The node sending heartbeats.</param>
/// <returns>An organized ring of unique nodes.</returns>
public IImmutableSet <UniqueAddress> Receivers(UniqueAddress sender)
{
if (_useAllAsReceivers)
{
return(NodeRing.Remove(sender));
}
else
{
// Pick nodes from the iterator until n nodes that are not unreachable have been selected.
// Intermediate unreachable nodes up to `monitoredByNrOfMembers` are also included in the result.
// The reason for not limiting it to strictly monitoredByNrOfMembers is that the leader must
// be able to continue its duties (e.g. removal of downed nodes) when many nodes are shutdown
// at the same time and nobody in the remaining cluster is monitoring some of the shutdown nodes.
(int, ImmutableSortedSet <UniqueAddress>) Take(int n, IEnumerator <UniqueAddress> iter, ImmutableSortedSet <UniqueAddress> acc, ImmutableHashSet <UniqueAddress> unreachable, int monitoredByNumberOfNodes)
{
while (true)
{
if (iter.MoveNext() == false || n == 0)
{
iter.Dispose(); // dispose enumerator
return(n, acc);
}
else
{
var next = iter.Current;
var isUnreachable = unreachable.Contains(next);
if (isUnreachable && acc.Count >= monitoredByNumberOfNodes)
{
}
else if (isUnreachable)
{
acc = acc.Add(next);
}
else
{
n = n - 1;
acc = acc.Add(next);
}
}
}
}
var(remaining, slice1) = Take(MonitoredByNumberOfNodes, NodeRing.From(sender).Skip(1).GetEnumerator(), ImmutableSortedSet <UniqueAddress> .Empty, Unreachable, MonitoredByNumberOfNodes);
IImmutableSet <UniqueAddress> slice = remaining == 0
? slice1 // or, wrap-around
: Take(remaining, NodeRing.TakeWhile(x => x != sender).GetEnumerator(), slice1, Unreachable, MonitoredByNumberOfNodes).Item2;
return(slice);
}
}
public ImmutableHashSet <UniqueAddress> Receivers(UniqueAddress sender)
{
if (_useAllAsReceivers)
{
return(NodeRing.Remove(sender).ToImmutableHashSet());
}
var slice = NodeRing.From(sender).Skip(1).Take(MonitoredByNumberOfNodes).ToList(); //grab members furthest from this peer
if (slice.Count < MonitoredByNumberOfNodes)
{
slice = slice.Concat(NodeRing.Take(MonitoredByNumberOfNodes - slice.Count)).ToList();
}
return(slice.ToImmutableHashSet());
}
