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Merge pull request #2 from xiangli-cmu/addIndex

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Add index
This commit is contained in:
Xiang Li 2013-06-29 15:36:11 -07:00
commit 56244a6d40
3 changed files with 110 additions and 30 deletions
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8
command.go
View File

@ -33,7 +33,7 @@ func (c *SetCommand) CommandName() string {
// Set the value of key to value
func (c *SetCommand) Apply(server *raft.Server) (interface{}, error) {
return store.Set(c.Key, c.Value, c.ExpireTime)
return store.Set(c.Key, c.Value, c.ExpireTime, server.CommittedIndex())
}
// Get the path for http request
@ -73,7 +73,7 @@ func (c *DeleteCommand) CommandName() string {
// Delete the key
func (c *DeleteCommand) Apply(server *raft.Server) (interface{}, error) {
return store.Delete(c.Key)
return store.Delete(c.Key, server.CommittedIndex())
}
// Watch command
@ -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

82
store/store.go
View File

@ -27,6 +27,15 @@ type Store struct {
// the string channel to send messages to the outside world
// 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
}
type Node struct {
@ -43,14 +52,19 @@ type Node struct {
type Response struct {
Action int `json:"action"`
Key string `json:"key"`
OldValue string `json:"oldValue"`
NewValue string `json:"newValue"`
PrevValue string `json:"prevValue"`
Value string `json:"Value"`
// if the key existed before the action, this field should be true
// if the key did not exist before the action, this field should be false
Exist bool `json:"exist"`
Expiration time.Time `json:"expiration"`
// countdown until expiration in seconds
TTL int64 `json:"TTL"`
Index uint64 `json:"index"`
}
func init() {
@ -62,6 +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
}
@ -76,7 +92,12 @@ func (s *Store) SetMessager(messager *chan string) {
}
// set the key to value, return the old value if the key exists
func Set(key string, value string, expireTime time.Time) ([]byte, error) {
func Set(key string, value string, expireTime time.Time, index uint64) ([]byte, error) {
//update index
s.Index = index
key = "/" + key
key = path.Clean(key)
@ -88,7 +109,15 @@ func Set(key string, value string, expireTime time.Time) ([]byte, error) {
// the key may be expired, we should not add the node
// also if the node exist, we need to delete the node
if isExpire && expireTime.Sub(time.Now()) < 0 {
return Delete(key)
return Delete(key, index)
}
var TTL int64
// update ttl
if isExpire {
TTL = int64(expireTime.Sub(time.Now()) / time.Second)
} else {
TTL = -1
}
// get the node
@ -108,12 +137,13 @@ func Set(key string, value string, expireTime time.Time) ([]byte, error) {
node.update = make(chan time.Time)
go expire(key, node.update, expireTime)
}
}
// update the information of the node
s.Nodes[key] = Node{value, expireTime, node.update}
resp := Response{SET, key, node.Value, value, true, expireTime}
resp := Response{SET, key, node.Value, value, true, expireTime, TTL, index}
msg, err := json.Marshal(resp)
@ -125,9 +155,11 @@ func Set(key string, value string, expireTime time.Time) ([]byte, error) {
*s.messager <- string(msg)
}
s.Responses = append(s.Responses, resp)
return msg, err
// add new node
// add new node
} else {
update := make(chan time.Time)
@ -138,7 +170,7 @@ func Set(key string, value string, expireTime time.Time) ([]byte, error) {
go expire(key, update, expireTime)
}
resp := Response{SET, key, "", value, false, expireTime}
resp := Response{SET, key, "", value, false, expireTime, TTL, index}
msg, err := json.Marshal(resp)
@ -150,7 +182,9 @@ func Set(key string, value string, expireTime time.Time) ([]byte, error) {
*s.messager <- string(msg)
}
s.Responses = append(s.Responses, resp)
fmt.Println(len(s.Responses), " ")
return msg, err
}
}
@ -170,7 +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}
resp := Response{DELETE, key, node.Value, "", true, node.ExpireTime, 0, s.Index}
msg, err := json.Marshal(resp)
@ -207,14 +241,30 @@ func Get(key string) Response {
node, ok := s.Nodes[key]
if ok {
return Response{GET, key, node.Value, node.Value, true, node.ExpireTime}
var TTL int64
var isExpire bool = false
isExpire = !node.ExpireTime.Equal(PERMANENT)
// update ttl
if isExpire {
TTL = int64(node.ExpireTime.Sub(time.Now()) / time.Second)
} else {
TTL = -1
}
return Response{GET, key, node.Value, node.Value, true, node.ExpireTime, TTL, s.Index}
} else {
return Response{GET, key, "", "", false, time.Unix(0, 0)}
return Response{GET, key, "", "", false, time.Unix(0, 0), 0, s.Index}
}
}
// delete the key
func Delete(key string) ([]byte, error) {
func Delete(key string, index uint64) ([]byte, error) {
//update index
s.Index = index
key = path.Clean(key)
node, ok := s.Nodes[key]
@ -233,7 +283,7 @@ func Delete(key string) ([]byte, error) {
}
resp := Response{DELETE, key, node.Value, "", true, node.ExpireTime}
resp := Response{DELETE, key, node.Value, "", true, node.ExpireTime, 0, index}
msg, err := json.Marshal(resp)
@ -245,11 +295,15 @@ func Delete(key string) ([]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)})
resp := Response{DELETE, key, "", "", false, time.Unix(0, 0), 0, index}
s.Responses = append(s.Responses, resp)
return json.Marshal(resp)
}
}

50
store/watcher.go
View File

@ -3,11 +3,7 @@ package store
import (
"path"
"strings"
)
const (
SHORT = iota
LONG
"fmt"
)
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 {