The library to syncronize app nodes by using zookeeper backend.
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nodesync/nodesync.go

60 lines
1.2 KiB

package sync
import (
"path"
"github.com/go-zookeeper/zk"
)
// NodeSync structure
type NodeSync struct {
Zk *zk.Conn
rootPath string
}
// Inside private environment keep everything open
var defaultAcl = zk.WorldACL(zk.PermAll)
// New creates a new nodesync instance
func New(zkconn *zk.Conn, rootPath string) (nodeSync *NodeSync, err error) {
nodeSync = &NodeSync{Zk: zkconn, rootPath: rootPath}
err = nodeSync.createRecursively(rootPath, defaultAcl)
if err != nil {
nodeSync = nil
}
return
}
// Fetch returns node data
func (s *NodeSync) Fetch(where string, key string) (current []byte, err error) {
workingPath := path.Join(s.rootPath, where, key)
current, _, err = s.Zk.Get(workingPath)
return
}
// FetchAndSet replaces zookeeper key with new value bytes and returns old if exists
func (s *NodeSync) FetchAndSet(where string, key string, value []byte) (old []byte, err error) {
workingPath := path.Join(s.rootPath, where, key)
err = s.createRecursively(workingPath, defaultAcl)
if err != nil {
return
}
var ver int32 = -1
old, stat, err := s.Zk.Get(workingPath)
if err == nil {
ver = stat.Version
}
_, err = s.Zk.Set(workingPath, value, ver)
return old, err
}