Add helper function to sort children nodes by the sequenced postfix

helpers.go

@@ -4,6 +4,8 @@ import (
 	"github.com/go-zookeeper/zk"
 
 	"fmt"
+	"path"
+	"sort"
 	"strings"
 )
 
@@ -46,3 +48,27 @@ func (s *NodeSync) createRecursively(path string, acl []zk.ACL) error {
 
 	return nil
 }
+
+// sortChildren sorts sequenced zookeeper nodes by sequence id
+// sequence id is a last part of node key and always consists of 10 digits
+func sortChildren(children []string) []string {
+
+	var sorted []string
+	for _, child := range children {
+		if len(child) <= sequenceLen {
+			continue
+		}
+
+		sorted = append(sorted, child)
+	}
+
+	sort.SliceStable(sorted, func(i, j int) bool {
+
+		_, a := path.Split(sorted[i])
+		_, b := path.Split(sorted[j])
+
+		return a[len(a)-sequenceLen:] < b[len(b)-sequenceLen:]
+	})
+
+	return sorted
+}

nodesync.go

@@ -16,6 +16,9 @@ type NodeSync struct {
 // Inside private environment keep everything open
 var defaultAcl = zk.WorldACL(zk.PermAll)
 
+// The length of a postfix sequence, see http://zookeeper.apache.org/doc/current/zookeeperProgrammers.html#Sequence+Nodes+--+Unique+Naming
+var sequenceLen = 10
+
 // New creates a new nodesync instance
 func New(zkconn *zk.Conn, rootPath string) (nodeSync *NodeSync, err error) {