/// <summary>
/// Receives changes from peer nodes, merges remote with local gossip nodes, then publishes
/// changes to the event stream for load balancing router consumption, and gossip back.
/// </summary>
private void ReceiveGossip(MetricsGossipEnvelope envelope)
{
// remote node might not have same view of member nodes, this side should only care
// about nodes that are known here, otherwise removed nodes can come back
var otherGossip = envelope.Gossip.Filter(_nodes.Select(n => n).ToImmutableHashSet());
_latestGossip = _latestGossip.Merge(otherGossip);
// changes will be published in the period collect task
if (!envelope.Reply)
{
ReplyGossipTo(envelope.FromAddress);
}
}
private Msg.MetricsGossipEnvelope MetricsGossipEnvelopeToProto(MetricsGossipEnvelope envelope)
{
var mgossip = envelope.Gossip;
var allAddresses = mgossip.Nodes.Select(x => x.Address).ToList();
var addressMapping = allAddresses.ZipWithIndex();
var allMetricNames = mgossip.Nodes.Aggregate(ImmutableHashSet.Create <string>(),
(set, metrics) => set = set.Union(metrics.Metrics.Select(x => x.Name)));
var metricNamesMapping = allMetricNames.ZipWithIndex();
Func <Address, int> mapAddress = address => MapWithErrorMessage(addressMapping, address, "address");
Func <string, int> mapName = name => MapWithErrorMessage(metricNamesMapping, name, "address");
Func <EWMA, Msg.NodeMetrics.Types.EWMA.Builder> ewmaToProto = ewma => ewma == null ? null :
Msg.NodeMetrics.Types.EWMA.CreateBuilder().SetAlpha(ewma.Alpha).SetValue(ewma.Value);
// we set all metric types as doubles, since we don't have a convenient Number base class like Scala
Func <double, Msg.NodeMetrics.Types.Number.Builder> numberToProto = d => Msg.NodeMetrics.Types.Number.CreateBuilder()
.SetType(Msg.NodeMetrics.Types.NumberType.Double)
.SetValue64((ulong)BitConverter.DoubleToInt64Bits(d));
Func <Metric, Msg.NodeMetrics.Types.Metric.Builder> metricToProto = metric =>
{
var builder =
Msg.NodeMetrics.Types.Metric.CreateBuilder()
.SetNameIndex(mapName(metric.Name))
.SetNumber(numberToProto(metric.Value));
var ewmaBuilder = ewmaToProto(metric.Average);
return(ewmaBuilder != null?builder.SetEwma(ewmaBuilder) : builder);
};
Func <NodeMetrics, Msg.NodeMetrics.Builder> nodeMetricsToProto = metrics => Msg.NodeMetrics.CreateBuilder()
.SetAddressIndex(mapAddress(metrics.Address))
.SetTimestamp(metrics.Timestamp)
.AddRangeMetrics(metrics.Metrics.Select(x => metricToProto(x).Build()));
var nodeMetrics = mgossip.Nodes.Select(x => nodeMetricsToProto(x).Build());
return(Msg.MetricsGossipEnvelope.CreateBuilder().SetFrom(AddressToProto(envelope.From)).SetGossip(
Msg.MetricsGossip.CreateBuilder()
.AddRangeAllAddresses(allAddresses.Select(x => AddressToProto(x).Build()))
.AddRangeAllMetricNames(allMetricNames).AddRangeNodeMetrics(nodeMetrics))
.SetReply(envelope.Reply)
.Build());
}
private void SendGossip(Akka.Actor.Address address, MetricsGossipEnvelope envelope)
{
Context.ActorSelection(Self.Path.ToStringWithAddress(address)).Tell(envelope);
}
