watch sinceindex works

command.go

@@ -87,10 +87,10 @@ func (c *WatchCommand) CommandName() string {
 }
 
 func (c *WatchCommand) Apply(server *raft.Server) (interface{}, error) {
-	ch := make(chan store.Response)
+	ch := make(chan store.Response, 1)
 
 	// add to the watchers list
-	store.AddWatcher(c.Key, ch, 0)
+	store.AddWatcher(c.Key, ch, 1)
 
 	// wait for the notification for any changing
 	res := <-ch

store/store.go

@@ -28,8 +28,14 @@ type Store struct {
 	// now we use it to send changes to the hub of the web service
 	messager *chan string
 
+	// previous responses
+	Responses []Response
+
+	// at some point, we may need to compact the Response
+	ResponseStartIndex uint64
+
 	// current Index
-	index uint64
+	Index uint64
 }
 
 type Node struct {
@@ -70,6 +76,8 @@ func init() {
 func createStore() *Store {
 	s := new(Store)
 	s.Nodes = make(map[string]Node)
+	s.Responses = make([]Response, 0)
+	s.ResponseStartIndex = 0
 	return s
 }
 
@@ -87,7 +95,9 @@ func (s *Store) SetMessager(messager *chan string) {
 func Set(key string, value string, expireTime time.Time, index uint64) ([]byte, error) {
 
 	//update index
-	s.index = index
+	s.Index = index
+	
+	key = "/" + key
 
 	key = path.Clean(key)
 
@@ -113,8 +123,6 @@ func Set(key string, value string, expireTime time.Time, index uint64) ([]byte,
 	// get the node
 	node, ok := s.Nodes[key]
 
-	
-
 	if ok {
 		// if node is not permanent before
 		// update its expireTime
@@ -147,6 +155,8 @@ func Set(key string, value string, expireTime time.Time, index uint64) ([]byte,
 			*s.messager <- string(msg)
 		}
 
+		s.Responses = append(s.Responses, resp)
+
 		return msg, err
 
 	// add new node
@@ -173,6 +183,8 @@ func Set(key string, value string, expireTime time.Time, index uint64) ([]byte,
 			*s.messager <- string(msg)
 		}
 		
+		s.Responses = append(s.Responses, resp)
+		fmt.Println(len(s.Responses), " ")
 		return msg, err
 	}
 }
@@ -192,7 +204,7 @@ func expire(key string, update chan time.Time, expireTime time.Time) {
 
 				delete(s.Nodes, key)
 
-				resp := Response{DELETE, key, node.Value, "", true, node.ExpireTime, 0, s.index}
+				resp := Response{DELETE, key, node.Value, "", true, node.ExpireTime, 0, s.Index}
 
 				msg, err := json.Marshal(resp)
 
@@ -241,16 +253,17 @@ func Get(key string) Response {
 			TTL = -1
 		}
 
-		return Response{GET, key, node.Value, node.Value, true, node.ExpireTime, TTL, s.index}
+		return Response{GET, key, node.Value, node.Value, true, node.ExpireTime, TTL, s.Index}
 	} else {
-		return Response{GET, key, "", "", false, time.Unix(0, 0), 0, s.index}
+
+		return Response{GET, key, "", "", false, time.Unix(0, 0), 0, s.Index}
 	}
 }
 
 // delete the key
 func Delete(key string, index uint64) ([]byte, error) {
 	//update index
-	s.index = index
+	s.Index = index
 
 	key = path.Clean(key)
 
@@ -282,11 +295,15 @@ func Delete(key string, index uint64) ([]byte, error) {
 			*s.messager <- string(msg)
 		}
 
+		s.Responses = append(s.Responses, resp)
 		return msg, err
 
 	} else {
 
-		return json.Marshal(Response{DELETE, key, "", "", false, time.Unix(0, 0), 0, index})
+		resp := Response{DELETE, key, "", "", false, time.Unix(0, 0), 0, index}
+		s.Responses = append(s.Responses, resp)
+
+		return json.Marshal(resp)
 	}
 }
 

store/watcher.go

@@ -3,11 +3,7 @@ package store
 import (
 	"path"
 	"strings"
-)
+	"fmt"
-
-const (
-	SHORT = iota
-	LONG
 )
 
 type WatcherHub struct {
@@ -16,7 +12,6 @@ type WatcherHub struct {
 
 type Watcher struct {
 	c     chan Response
-	wType int
 }
 
 // global watcher
@@ -39,22 +34,32 @@ func GetWatcherHub() *WatcherHub {
 }
 
 // register a function with channel and prefix to the watcher
-func AddWatcher(prefix string, c chan Response, wType int) error {
+func AddWatcher(prefix string, c chan Response, sinceIndex uint64) error {
 
 	prefix = "/" + path.Clean(prefix)
 
+	if sinceIndex != 0 && sinceIndex >= s.ResponseStartIndex {
+
+		for i := sinceIndex; i < s.Index; i++ {
+			if check(prefix, i) {
+				c <- s.Responses[i]
+				return nil
+			}
+		}
+	}
+
 	_, ok := w.watchers[prefix]
 
 	if !ok {
 
 		w.watchers[prefix] = make([]Watcher, 0)
 
-		watcher := Watcher{c, wType}
+		watcher := Watcher{c}
 
 		w.watchers[prefix] = append(w.watchers[prefix], watcher)
 	} else {
 
-		watcher := Watcher{c, wType}
+		watcher := Watcher{c}
 
 		w.watchers[prefix] = append(w.watchers[prefix], watcher)
 	}
@@ -62,6 +67,30 @@ func AddWatcher(prefix string, c chan Response, wType int) error {
 	return nil
 }
 
+// check if the response has what we are waching
+func check(prefix string, index uint64) bool {
+
+	index = index - s.ResponseStartIndex
+
+	if index < 0 {
+		return false
+	}
+
+	path := s.Responses[index].Key
+	fmt.Println("checking ", path, " ", prefix)
+	if strings.HasPrefix(path, prefix) {
+		fmt.Println("checking found")
+		prefixLen := len(prefix)
+		if len(path) == prefixLen || path[prefixLen] == '/' {
+			return true
+		}
+
+	}
+
+	return false
+}
+
+
 // notify the watcher a action happened
 func notify(resp Response) error {
 	resp.Key = path.Clean(resp.Key)
@@ -81,9 +110,6 @@ func notify(resp Response) error {
 			// notify all the watchers
 			for _, watcher := range watchers {
 				watcher.c <- resp
-				if watcher.wType == LONG {
-					newWatchers = append(newWatchers, watcher)
-				}
 			}
 
 			if len(newWatchers) == 0 {