Memcached support

README.md

@@ -36,12 +36,20 @@ Zookeeper HTTP rest API
 Usage of ./zoorest:
   -listen string
     	Address to listen (default "127.0.0.1:8889")
+  -mc
+    	Enable memcached support
+  -mchosts string
+    	Memcached servers. Comma separated (default "127.0.0.1:11211")
+  -mcprefix string
+    	Memcached key prefix (default "zoorest")
   -path string
     	Zk root path (default "/")
   -zk string
     	Zk servers. Comma separated (default "127.0.0.1:2181")
 ```
 
+NOTE: If memcached support is enabled zkStat metrics will not be returned.
+
 ## API
 
 ### List node childrens

build.sh

@@ -16,7 +16,7 @@ ENTRYPOINT go build -ldflags "-linkmode external -extldflags -static" && mv zoor
 EOF
 
 # Build builder
-docker build -t zoorest_builder -f Dockerfile.builder .
+docker build --no-cache -t zoorest_builder -f Dockerfile.builder .
 # Build bin
 docker run -v $(pwd)/out:/out zoorest_builder
 

main.go

@@ -7,9 +7,12 @@ import (
 )
 
 var (
-	zk     string
+	zk       string
-	listen string
+	listen   string
-	path   string
+	path     string
+	mc       bool
+	mcHosts  string
+	mcPrefix string
 )
 
 // init ...
@@ -17,24 +20,39 @@ func init() {
 	flag.StringVar(&zk, "zk", "127.0.0.1:2181", "Zk servers. Comma separated")
 	flag.StringVar(&listen, "listen", "127.0.0.1:8889", "Address to listen")
 	flag.StringVar(&path, "path", "/", "Zk root path")
+	flag.BoolVar(&mc, "mc", false, "Enable memcached support")
+	flag.StringVar(&mcHosts, "mchosts", "127.0.0.1:11211", "Memcached servers. Comma separated")
+	flag.StringVar(&mcPrefix, "mcprefix", "zoorest", "Memcached key prefix")
 	flag.Parse()
 }
 
 // main ...
 func main() {
 	var z rest.Zk
-	hosts := strings.Split(zk, ",")
+	hosts := getSlice(zk, ",")
 	z.Hosts = hosts
 	conn, err := z.InitConnection()
 	if err != nil {
 		panic(err)
 	}
 
-	zoo := rest.ZooNode{
+	var zoo rest.ZooNode
-		path,
+	zoo.Path = path
-		conn,
+	zoo.Conn = conn
-		z,
+	zoo.Zoo = z
-	}
+
+	var MC rest.MC
+	MC.Hosts = getSlice(mcHosts, ",")
+	MC.Prefix = mcPrefix
+	MC.Enabled = mc
+	MC.Client = MC.InitConnection()
+
+	zoo.MC = MC
 
 	rest.Serve(listen, zoo)
 }
+
+// getSlice returm slice
+func getSlice(s string, delimeter string) []string {
+	return strings.Split(s, ",")
+}

rest/cache.go

@@ -0,0 +1,58 @@
+package rest
+
+import (
+	"crypto/md5"
+	"github.com/bradfitz/gomemcache/memcache"
+	"strings"
+)
+
+// Memcached connection settings
+type MC struct {
+	Enabled bool     `json:"enabled"`
+	Hosts   []string `json:"hosts"`
+	Prefix  string   `json:"prefix"`
+	Client  *memcache.Client
+}
+
+// InitConnection to memcached cluster
+func (mc MC) InitConnection() *memcache.Client {
+	client := memcache.New(mc.Hosts...)
+	return client
+}
+
+// StoreToCache save data to memecache
+func (mc MC) StoreToCache(key string, data []byte) error {
+	prefixed_key := strings.Join([]string{mc.Prefix, key}, "_")
+
+	var item memcache.Item
+	// item.Key = hashKey(prefixed_key)
+	item.Key = prefixed_key
+	item.Value = data
+
+	// store
+	err := mc.Client.Set(&item)
+
+	return err
+}
+
+// (mc MC) GetFromCache ...
+func (mc MC) GetFromCache(key string) ([]byte, error) {
+	var data *memcache.Item
+	prefixed_key := strings.Join([]string{mc.Prefix, key}, "_")
+
+	// data, err := mc.Client.Get(hashKey(prefixed_key))
+	data, err := mc.Client.Get(prefixed_key)
+	if err != nil {
+		return []byte(""), err
+	}
+
+	return data.Value, err
+}
+
+// hashKey return md5sum of prefixed_key
+func hashKey(key string) string {
+	h := md5.New()
+	sum := h.Sum([]byte(key))
+
+	return string(sum)
+}

rest/zoo.go

@@ -12,6 +12,7 @@ type ZooNode struct {
 	Path string
 	Conn *zk.Conn
 	Zoo  Zk
+	MC   MC
 }
 
 //Zk Zookeeper connection settings
@@ -43,10 +44,23 @@ func (z ZooNode) GetChildrens(path string) Ls {
 		lsPath = strings.Replace(lsPath, "//", "/", 1)
 	}
 
-	log.Print("ls: ", lsPath)
+	log.Print("V1 LS: ", lsPath)
 
 	var l Ls
 	l.State = "OK"
+	l.Path = path
+
+	if z.MC.Enabled {
+		data, err := z.MC.GetFromCache(lsPath)
+		if err != nil {
+			log.Print("V1 LS ERROR: ", err.Error())
+		} else {
+			log.Print("We are get it from memecache!")
+			childrens := strings.Split(string(data), ",")
+			l.Childrens = childrens
+			return l
+		}
+	}
 
 	childrens, zkStat, err := z.Conn.Children(lsPath)
 	if err != nil {
@@ -55,15 +69,22 @@ func (z ZooNode) GetChildrens(path string) Ls {
 		return l
 	}
 
+	// Store to cache
+	if z.MC.Enabled {
+		err := z.MC.StoreToCache(lsPath, []byte(strings.Join(childrens, ",")))
+		if err != nil {
+			log.Print("V1 LS: ", err.Error())
+		}
+	}
+
 	l.Error = ""
 	l.Childrens = childrens
-	l.Path = path
 	l.ZkStat = zkStat
 
 	return l
 }
 
-// GetNode ...
+// GetNode data
 func (z ZooNode) GetNode(path string) Get {
 	var getPath string
 	getPath = strings.Join([]string{z.Path, path}, "")
@@ -75,10 +96,21 @@ func (z ZooNode) GetNode(path string) Get {
 		getPath = strings.Replace(getPath, "//", "/", 1)
 	}
 
-	log.Print("get: ", getPath)
+	log.Print("V1 GET: ", getPath)
 
 	var g Get
 	g.State = "OK"
+	g.Path = path
+
+	// Get data from memcached
+	if z.MC.Enabled {
+		if data, err := z.MC.GetFromCache(getPath); err != nil {
+			log.Print("V1 GET: ", err.Error())
+		} else {
+			g.Data = data
+			return g
+		}
+	}
 
 	data, zkStat, err := z.Conn.Get(getPath)
 	if err != nil {
@@ -87,9 +119,16 @@ func (z ZooNode) GetNode(path string) Get {
 		return g
 	}
 
+	// Store to cache
+	if z.MC.Enabled {
+		err := z.MC.StoreToCache(getPath, data)
+		if err != nil {
+			log.Print("V1 LS: ", err.Error())
+		}
+	}
+
 	g.Error = ""
 	g.Data = data
-	g.Path = path
 	g.ZkStat = zkStat
 
 	return g
@@ -149,6 +188,12 @@ func (z ZooNode) UpdateNode(path string, content []byte) string {
 		return err.Error()
 	}
 
+	if z.MC.Enabled {
+		if err := z.MC.StoreToCache(upPath, content); err != nil {
+			log.Print("V1 update ERROR: ", err.Error())
+		}
+	}
+
 	return path
 }
 
@@ -167,6 +212,12 @@ func (z ZooNode) CreateChild(path string, content []byte) string {
 		return err.Error()
 	}
 
+	if z.MC.Enabled {
+		if err := z.MC.StoreToCache(crPath, content); err != nil {
+			log.Print("V1 create ERROR: ", err.Error())
+		}
+	}
+
 	return path
 }