[#1164] cli: Improve `object nodes` performance

Do complex EC object parts flatten concurrently.

Signed-off-by: Dmitrii Stepanov <d.stepanov@yadro.com>

cmd/frostfs-cli/modules/object/nodes.go

@@ -33,7 +33,10 @@ const (
 	verifyPresenceAllFlag = "verify-presence-all"
 )
 
-var errNoAvailableEndpoint = errors.New("failed to create client: no available endpoint")
+var (
+	errNoAvailableEndpoint    = errors.New("failed to create client: no available endpoint")
+	errMalformedComplexObject = errors.New("object consists of EC and non EC parts")
+)
 
 type phyObject struct {
 	containerID               cid.ID
@@ -180,30 +183,66 @@ func getCompexObjectMembers(cmd *cobra.Command, cnrID cid.ID, objID oid.ID, cli
 
 func flattenComplexMembersIfECContainer(cmd *cobra.Command, cnrID cid.ID, members []oid.ID, prmHead internalclient.HeadObjectPrm) []phyObject {
 	result := make([]phyObject, 0, len(members))
+	var resultGuard sync.Mutex
+
+	if len(members) == 0 {
+		return result
+	}
+
+	prmHead.SetRawFlag(true) // to get an error instead of whole object
+
+	first := members[0]
 	var addrObj oid.Address
 	addrObj.SetContainer(cnrID)
-	prmHead.SetRawFlag(true) // to get an error instead of whole object
-	for _, partObjID := range members {
-		addrObj.SetObject(partObjID)
-		prmHead.SetAddress(addrObj)
+	addrObj.SetObject(first)
+	prmHead.SetAddress(addrObj)
 
-		_, err := internalclient.HeadObject(cmd.Context(), prmHead)
-		var ecInfoError *objectSDK.ECInfoError
-		if errors.As(err, &ecInfoError) {
-			chunks := getECObjectChunks(cmd, cnrID, partObjID, ecInfoError)
-			result = append(result, chunks...)
-			continue
-		} else if err == nil { // not EC object, so all members must be phy objects
-			for _, member := range members {
-				result = append(result, phyObject{
-					containerID: cnrID,
-					objectID:    member,
-				})
-			}
-			break
+	_, err := internalclient.HeadObject(cmd.Context(), prmHead)
+	var ecInfoError *objectSDK.ECInfoError
+	if errors.As(err, &ecInfoError) {
+		chunks := getECObjectChunks(cmd, cnrID, first, ecInfoError)
+		result = append(result, chunks...)
+	} else if err == nil { // not EC object, so all members must be phy objects
+		for _, member := range members {
+			result = append(result, phyObject{
+				containerID: cnrID,
+				objectID:    member,
+			})
 		}
-		commonCmd.ExitOnErr(cmd, "failed to read EC chunk of complex object: %w", err)
+		return result
+	} else {
+		commonCmd.ExitOnErr(cmd, "failed to flatten parts of complex object: %w", err)
 	}
+
+	eg, egCtx := errgroup.WithContext(cmd.Context())
+	for idx := 1; idx < len(members); idx++ {
+		partObjID := members[idx]
+
+		eg.Go(func() error {
+			partHeadPrm := prmHead
+			var partAddr oid.Address
+			partAddr.SetContainer(cnrID)
+			partAddr.SetObject(partObjID)
+			partHeadPrm.SetAddress(partAddr)
+
+			_, err := internalclient.HeadObject(egCtx, partHeadPrm)
+			var ecInfoError *objectSDK.ECInfoError
+			if errors.As(err, &ecInfoError) {
+				chunks := getECObjectChunks(cmd, cnrID, partObjID, ecInfoError)
+
+				resultGuard.Lock()
+				defer resultGuard.Unlock()
+				result = append(result, chunks...)
+
+				return nil
+			} else if err == nil {
+				return errMalformedComplexObject
+			}
+			return err
+		})
+	}
+
+	commonCmd.ExitOnErr(cmd, "failed to flatten parts of complex object: %w", eg.Wait())
 	return result
 }