[#70] Add arrays of copies numbers for location constraints

Signed-off-by: Artem Tataurov <a.tataurov@yadro.com>

api/handler/api.go

@@ -3,7 +3,10 @@ package handler
 import (
 	"encoding/xml"
 	"errors"
+	"fmt"
 	"io"
+	"strconv"
+	"strings"
 	"time"
 
 	"git.frostfs.info/TrueCloudLab/frostfs-s3-gw/api"
@@ -32,6 +35,7 @@ type (
 		DefaultMaxAge              int
 		NotificatorEnabled         bool
 		CopiesNumber               uint32
+		CopiesNumbers              map[string][]uint32
 		ResolveZoneList            []string
 		IsResolveListAllow         bool // True if ResolveZoneList contains allowed zones
 		CompleteMultipartKeepalive time.Duration
@@ -78,3 +82,44 @@ func New(log *zap.Logger, obj layer.Client, notificator Notificator, cfg *Config
 		notificator: notificator,
 	}, nil
 }
+
+// pickCopiesNumbers chooses the return values following this logic:
+// 1) array of copies numbers sent in request's header has the highest priority
+// 2) array of copies numbers with corresponding location constraint provided in the config file
+// 3) default copies number from the config file wrapped into array
+func (h *handler) pickCopiesNumbers(metadata map[string]string, locationConstraint string) ([]uint32, error) {
+	copiesNumbersStr, ok := metadata[layer.AttributeFrostfsCopiesNumber]
+	if ok {
+		result, err := parseCopiesNumbers(copiesNumbersStr)
+		if err != nil {
+			return nil, err
+		}
+		return result, nil
+	}
+
+	copiesNumbers, ok := h.cfg.CopiesNumbers[locationConstraint]
+	if ok {
+		return copiesNumbers, nil
+	}
+
+	return []uint32{h.cfg.CopiesNumber}, nil
+}
+
+func parseCopiesNumbers(copiesNumbersStr string) ([]uint32, error) {
+	var result []uint32
+	copiesNumbersSplit := strings.Split(copiesNumbersStr, ",")
+
+	for i := range copiesNumbersSplit {
+		item := strings.ReplaceAll(copiesNumbersSplit[i], " ", "")
+		if len(item) == 0 {
+			continue
+		}
+		copiesNumber, err := strconv.ParseUint(item, 10, 32)
+		if err != nil {
+			return nil, fmt.Errorf("pasrse copies number: %w", err)
+		}
+		result = append(result, uint32(copiesNumber))
+	}
+
+	return result, nil
+}