[#1439] object: Sort nodes by priority metrics to compute GET request

Signed-off-by: Anton Nikiforov <an.nikiforov@yadro.com>

pkg/services/object_manager/placement/traverser.go

@@ -3,6 +3,7 @@ package placement
 import (
 	"errors"
 	"fmt"
+	"slices"
 	"sync"
 
 	"git.frostfs.info/TrueCloudLab/frostfs-node/pkg/network"
@@ -23,6 +24,11 @@ type Builder interface {
 	BuildPlacement(cid.ID, *oid.ID, netmap.PlacementPolicy) ([][]netmap.NodeInfo, error)
 }
 
+type NodeState interface {
+	// LocalNodeInfo return current node state in FrostFS API v2 NodeInfo structure.
+	LocalNodeInfo() *netmap.NodeInfo
+}
+
 // Option represents placement traverser option.
 type Option func(*cfg)
 
@@ -50,6 +56,10 @@ type cfg struct {
 	policy    netmap.PlacementPolicy
 
 	builder Builder
+
+	metrics []Metric
+
+	nodeState NodeState
 }
 
 const invalidOptsMsg = "invalid traverser options"
@@ -99,7 +109,22 @@ func NewTraverser(opts ...Option) (*Traverser, error) {
 	}
 
 	var rem []int
-	if cfg.flatSuccess != nil {
+	if len(cfg.metrics) > 0 && cfg.nodeState != nil {
+		rem = defaultCopiesVector(cfg.policy)
+		var unsortedVector []netmap.NodeInfo
+		var regularVector []netmap.NodeInfo
+		for i := range rem {
+			unsortedVector = append(unsortedVector, ns[i][:rem[i]]...)
+			regularVector = append(regularVector, ns[i][rem[i]:]...)
+		}
+		rem = []int{-1, -1}
+
+		sortedVector, err := sortVector(cfg, unsortedVector)
+		if err != nil {
+			return nil, err
+		}
+		ns = [][]netmap.NodeInfo{sortedVector, regularVector}
+	} else if cfg.flatSuccess != nil {
 		ns = flatNodes(ns)
 		rem = []int{int(*cfg.flatSuccess)}
 	} else {
@@ -157,6 +182,35 @@ func flatNodes(ns [][]netmap.NodeInfo) [][]netmap.NodeInfo {
 	return [][]netmap.NodeInfo{flat}
 }
 
+type nodeMetrics struct {
+	index   int
+	metrics []int
+}
+
+func sortVector(cfg *cfg, unsortedVector []netmap.NodeInfo) ([]netmap.NodeInfo, error) {
+	nm := make([]nodeMetrics, len(unsortedVector))
+	node := cfg.nodeState.LocalNodeInfo()
+
+	for i := range unsortedVector {
+		m := make([]int, len(cfg.metrics))
+		for j, pm := range cfg.metrics {
+			m[j] = pm.CalculateValue(node, &unsortedVector[i])
+		}
+		nm[i] = nodeMetrics{
+			index:   i,
+			metrics: m,
+		}
+	}
+	slices.SortFunc(nm, func(a, b nodeMetrics) int {
+		return slices.Compare(a.metrics, b.metrics)
+	})
+	sortedVector := make([]netmap.NodeInfo, len(unsortedVector))
+	for i := range unsortedVector {
+		sortedVector[i] = unsortedVector[nm[i].index]
+	}
+	return sortedVector, nil
+}
+
 // Node is a descriptor of storage node with information required for intra-container communication.
 type Node struct {
 	addresses network.AddressGroup
@@ -322,3 +376,17 @@ func WithCopyNumbers(v []uint32) Option {
 		c.copyNumbers = v
 	}
 }
+
+// WithPriorityMetrics use provided priority metrics to sort nodes.
+func WithPriorityMetrics(m []Metric) Option {
+	return func(c *cfg) {
+		c.metrics = m
+	}
+}
+
+// WithNodeState provide state of the current node.
+func WithNodeState(s NodeState) Option {
+	return func(c *cfg) {
+		c.nodeState = s
+	}
+}