[#97] Add a method IterateUserAttributes in Container

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

container/container.go

@@ -6,6 +6,7 @@ import (
 	"errors"
 	"fmt"
 	"strconv"
+	"strings"
 	"time"
 
 	"git.frostfs.info/TrueCloudLab/frostfs-api-go/v2/container"
@@ -296,7 +297,7 @@ func (x Container) PlacementPolicy() (res netmap.PlacementPolicy) {
 //
 // SetAttribute overwrites existing attribute value.
 //
-// See also Attribute, IterateAttributes.
+// See also Attribute, IterateAttributes, IterateUserAttributes.
 func (x *Container) SetAttribute(key, value string) {
 	if key == "" {
 		panic("empty attribute key")
@@ -324,7 +325,7 @@ func (x *Container) SetAttribute(key, value string) {
 // Attribute reads value of the Container attribute by key. Empty result means
 // attribute absence.
 //
-// See also SetAttribute, IterateAttributes.
+// See also SetAttribute, IterateAttributes, IterateUserAttributes.
 func (x Container) Attribute(key string) string {
 	attrs := x.v2.GetAttributes()
 	for i := range attrs {
@@ -347,6 +348,21 @@ func (x Container) IterateAttributes(f func(key, val string)) {
 	}
 }
 
+// IterateUserAttributes iterates over user Container attributes and passes them
+// into f. The handler MUST NOT be nil.
+//
+// See also SetAttribute, Attribute.
+func (x Container) IterateUserAttributes(f func(key, val string)) {
+	attrs := x.v2.GetAttributes()
+	for _, attr := range attrs {
+		var key = attr.GetKey()
+		if !strings.HasPrefix(key, container.SysAttributePrefix) &&
+			!strings.HasPrefix(key, container.SysAttributePrefixNeoFS) {
+			f(key, attr.GetValue())
+		}
+	}
+}
+
 // SetName sets human-readable name of the Container. Name MUST NOT be empty.
 //
 // See also Name.

container/container_test.go

@@ -150,7 +150,7 @@ func assertContainsAttribute(t *testing.T, m v2container.Container, key, val str
 }
 
 func TestContainer_Attribute(t *testing.T) {
-	const attrKey1, attrKey2 = "key1", "key2"
+	const attrKey1, attrKey2 = v2container.SysAttributePrefix + "key1", v2container.SysAttributePrefixNeoFS + "key2"
 	const attrVal1, attrVal2 = "val1", "val2"
 
 	val := containertest.Container()
@@ -158,6 +158,12 @@ func TestContainer_Attribute(t *testing.T) {
 	val.SetAttribute(attrKey1, attrVal1)
 	val.SetAttribute(attrKey2, attrVal2)
 
+	var i int
+	val.IterateUserAttributes(func(key, val string) {
+		i++
+	})
+	require.Equal(t, 1, i)
+
 	var msg v2container.Container
 	val.WriteToV2(&msg)