Initial commit

Initial public review release v0.10.0

lib/placement/neighbours.go

@@ -0,0 +1,69 @@
+package placement
+
+import (
+	"math"
+
+	"github.com/nspcc-dev/hrw"
+	"github.com/nspcc-dev/neofs-node/lib/netmap"
+	"github.com/nspcc-dev/neofs-node/lib/peers"
+	"go.uber.org/zap"
+)
+
+func calculateCount(n int) int {
+	if n < 30 {
+		return n
+	}
+
+	return int(1.4*math.Log(float64(n))+9) + 1
+}
+
+// Neighbours peers that which are distributed by hrw(seed)
+// If full flag is set, all set of peers returns.
+// Otherwise, result size depends on calculateCount function.
+func (p *placement) Neighbours(seed, epoch uint64, full bool) []peers.ID {
+	nm := p.nmStore.get(epoch)
+	if nm == nil {
+		p.log.Error("could not receive network state",
+			zap.Uint64("epoch", epoch),
+		)
+
+		return nil
+	}
+
+	rPeers := p.listPeers(nm.ItemsCopy(), !full)
+
+	hrw.SortSliceByValue(rPeers, seed)
+
+	if full {
+		return rPeers
+	}
+
+	var (
+		ln  = len(rPeers)
+		cut = calculateCount(ln)
+	)
+
+	if cut > ln {
+		cut = ln
+	}
+
+	return rPeers[:cut]
+}
+
+func (p *placement) listPeers(nodes netmap.Nodes, exclSelf bool) []peers.ID {
+	var (
+		id     = p.ps.SelfID()
+		result = make([]peers.ID, 0, len(nodes))
+	)
+
+	for i := range nodes {
+		key := peers.IDFromBinary(nodes[i].PubKey)
+		if exclSelf && id.Equal(key) {
+			continue
+		}
+
+		result = append(result, key)
+	}
+
+	return result
+}