[#1640] object: Add priority metric based on geo distance

Change-Id: I3a7ea4fc4807392bf50e6ff1389c61367c953074
Signed-off-by: Anton Nikiforov <an.nikiforov@yadro.com>

pkg/services/object_manager/placement/metrics.go

@@ -2,24 +2,90 @@ package placement
 
 import (
 	"errors"
+	"fmt"
+	"maps"
+	"math"
 	"strings"
+	"sync"
+	"sync/atomic"
 
+	locodedb "git.frostfs.info/TrueCloudLab/frostfs-locode-db/pkg/locode/db"
+	locodebolt "git.frostfs.info/TrueCloudLab/frostfs-locode-db/pkg/locode/db/boltdb"
 	"git.frostfs.info/TrueCloudLab/frostfs-sdk-go/netmap"
 )
 
 const (
 	attrPrefix = "$attribute:"
+
+	geoDistance = "$geoDistance"
 )
 
 type Metric interface {
 	CalculateValue(*netmap.NodeInfo, *netmap.NodeInfo) int
 }
 
-func ParseMetric(raw string) (Metric, error) {
-	if attr, found := strings.CutPrefix(raw, attrPrefix); found {
-		return NewAttributeMetric(attr), nil
+type metricsParser struct {
+	locodeDBPath string
+	locodes      map[string]locodedb.Point
+}
+
+type MetricParser interface {
+	ParseMetrics([]string) ([]Metric, error)
+}
+
+func NewMetricsParser(locodeDBPath string) (MetricParser, error) {
+	return &metricsParser{
+		locodeDBPath: locodeDBPath,
+	}, nil
+}
+
+func (p *metricsParser) initLocodes() error {
+	if len(p.locodes) != 0 {
+		return nil
 	}
-	return nil, errors.New("unsupported priority metric")
+	if len(p.locodeDBPath) > 0 {
+		p.locodes = make(map[string]locodedb.Point)
+		locodeDB := locodebolt.New(locodebolt.Prm{
+			Path: p.locodeDBPath,
+		},
+			locodebolt.ReadOnly(),
+		)
+		err := locodeDB.Open()
+		if err != nil {
+			return err
+		}
+		defer locodeDB.Close()
+		err = locodeDB.IterateOverLocodes(func(k string, v locodedb.Point) {
+			p.locodes[k] = v
+		})
+		if err != nil {
+			return err
+		}
+		return nil
+	}
+	return errors.New("set path to locode database")
+}
+
+func (p *metricsParser) ParseMetrics(priority []string) ([]Metric, error) {
+	var metrics []Metric
+	for _, raw := range priority {
+		if attr, found := strings.CutPrefix(raw, attrPrefix); found {
+			metrics = append(metrics, NewAttributeMetric(attr))
+		} else if raw == geoDistance {
+			err := p.initLocodes()
+			if err != nil {
+				return nil, err
+			}
+			if len(p.locodes) == 0 {
+				return nil, fmt.Errorf("provide locodes database for metric %s", raw)
+			}
+			m := NewGeoDistanceMetric(p.locodes)
+			metrics = append(metrics, m)
+		} else {
+			return nil, fmt.Errorf("unsupported priority metric %s", raw)
+		}
+	}
+	return metrics, nil
 }
 
 // attributeMetric describes priority metric based on attribute.
@@ -41,3 +107,79 @@ func (am *attributeMetric) CalculateValue(from *netmap.NodeInfo, to *netmap.Node
 func NewAttributeMetric(attr string) Metric {
 	return &attributeMetric{attribute: attr}
 }
+
+// geoDistanceMetric describes priority metric based on attribute.
+type geoDistanceMetric struct {
+	locodes  map[string]locodedb.Point
+	distance *atomic.Pointer[map[string]int]
+	mtx      sync.Mutex
+}
+
+func NewGeoDistanceMetric(locodes map[string]locodedb.Point) Metric {
+	d := atomic.Pointer[map[string]int]{}
+	m := make(map[string]int)
+	d.Store(&m)
+	gm := &geoDistanceMetric{
+		locodes:  locodes,
+		distance: &d,
+	}
+	return gm
+}
+
+// CalculateValue return distance in kilometers between current node and provided,
+// if coordinates for provided node found. In other case return math.MaxInt.
+func (gm *geoDistanceMetric) CalculateValue(from *netmap.NodeInfo, to *netmap.NodeInfo) int {
+	fl := from.LOCODE()
+	tl := to.LOCODE()
+	if fl == tl {
+		return 0
+	}
+	m := gm.distance.Load()
+	if v, ok := (*m)[fl+tl]; ok {
+		return v
+	}
+	return gm.calculateDistance(fl, tl)
+}
+
+func (gm *geoDistanceMetric) calculateDistance(from, to string) int {
+	gm.mtx.Lock()
+	defer gm.mtx.Unlock()
+	od := gm.distance.Load()
+	if v, ok := (*od)[from+to]; ok {
+		return v
+	}
+	nd := maps.Clone(*od)
+	var dist int
+	pointFrom, okFrom := gm.locodes[from]
+	pointTo, okTo := gm.locodes[to]
+	if okFrom && okTo {
+		dist = int(distance(pointFrom.Latitude(), pointFrom.Longitude(), pointTo.Latitude(), pointTo.Longitude()))
+	} else {
+		dist = math.MaxInt
+	}
+	nd[from+to] = dist
+	gm.distance.Store(&nd)
+
+	return dist
+}
+
+// distance return amount of KM between two points.
+// Parameters are latitude and longitude of point 1 and 2 in decimal degrees.
+// Original implementation can be found here https://www.geodatasource.com/developers/go.
+func distance(lt1 float64, ln1 float64, lt2 float64, ln2 float64) float64 {
+	radLat1 := math.Pi * lt1 / 180
+	radLat2 := math.Pi * lt2 / 180
+	radTheta := math.Pi * (ln1 - ln2) / 180
+
+	dist := math.Sin(radLat1)*math.Sin(radLat2) + math.Cos(radLat1)*math.Cos(radLat2)*math.Cos(radTheta)
+
+	if dist > 1 {
+		dist = 1
+	}
+
+	dist = math.Acos(dist)
+	dist = dist * 180 / math.Pi
+	dist = dist * 60 * 1.1515 * 1.609344
+
+	return dist
+}