node: 断网重连

bin/node/server.go

@@ -28,7 +28,7 @@ func main() {
 		return
 	}
 
-	n, err := node.NewNode(conf.Config.Etcd)
+	n, err := node.NewNode(conf.Config)
 	if err != nil {
 		log.Error(err.Error())
 		return
@@ -41,7 +41,7 @@ func main() {
 
 	go n.Run()
 
-	log.Noticef("cronsun node[%s] pid[%s] service started, Ctrl+C or send kill sign to exit", n.Key, n.PID)
+	log.Noticef("cronsun %s service started, Ctrl+C or send kill sign to exit", n.String())
 	// 注册退出事件
 	event.On(event.EXIT, n.Stop)
 	// 监听退出信号

conf/conf.go

@@ -37,6 +37,7 @@ type Conf struct {
 
 	Proc string // proc 路径
 	Cmd  string // cmd 路径
+	Sep  string // etcd key 的连接符
 
 	Ttl int64 // 节点超时时间，单位秒
 

conf/files/base.json.sample

@@ -1,7 +1,8 @@
 {
     "Proc": "/cronsun/proc",
     "Cmd": "/cronsun/cmd",
-    "Timeout": 10,
+    "Sep": "/",
+    "Ttl": 10,
     "Log": "@extend:log.json",
     "Etcd": "@extend:etcd.json"
 }

node/node.go

@@ -10,33 +10,39 @@ import (
 
 	client "github.com/coreos/etcd/clientv3"
 
+	"sunteng/commons/log"
 	"sunteng/commons/util"
 	"sunteng/cronsun/conf"
+	"syscall"
 )
 
 const (
 	ReqTimeout = 2 * time.Second
-
-	Spliter = "/"
 )
 
 // Node 执行 cron 命令服务的结构体
 type Node struct {
 	*client.Client
 
+	ttl    time.Duration
+	prefix string
+
 	Key string
 	PID string
 
 	lID client.LeaseID // lease id
+	lch <-chan *client.LeaseKeepAliveResponse
+
+	done chan struct{}
 }
 
-func NewNode(cfg client.Config) (n *Node, err error) {
+func NewNode(cfg *conf.Conf) (n *Node, err error) {
 	ip, err := util.GetLocalIP()
 	if err != nil {
 		return
 	}
 
-	cli, err := client.New(cfg)
+	cli, err := client.New(cfg.Etcd)
 	if err != nil {
 		return
 	}
@@ -44,12 +50,21 @@ func NewNode(cfg client.Config) (n *Node, err error) {
 	n = &Node{
 		Client: cli,
 
-		Key: conf.Config.Proc + Spliter + ip.String(),
+		ttl:    time.Duration(cfg.Ttl) * time.Second,
+		prefix: cfg.Proc + cfg.Sep,
+
+		Key: cfg.Proc + cfg.Sep + ip.String(),
 		PID: strconv.Itoa(os.Getpid()),
+
+		done: make(chan struct{}),
 	}
 	return
 }
 
+func (n *Node) String() string {
+	return "node[" + n.Key[len(n.prefix):] + "] pid[" + n.PID + "]"
+}
+
 // 注册到 /cronsun/proc/xx
 func (n *Node) Register() (err error) {
 	pid, err := n.Exist()
@@ -58,7 +73,7 @@ func (n *Node) Register() (err error) {
 	}
 
 	if pid != -1 {
-		return fmt.Errorf("node[%s] pid[%d] exist", n.Key, pid)
+		return fmt.Errorf("node[%s] pid[%d] exist", n.Key[len(n.prefix):], pid)
 	}
 
 	resp, err := n.Client.Grant(context.TODO(), conf.Config.Ttl)
@@ -69,11 +84,13 @@ func (n *Node) Register() (err error) {
 	if _, err = n.Client.Put(context.TODO(), n.Key, n.PID, client.WithLease(resp.ID)); err != nil {
 		return
 	}
-	if _, err = n.Client.KeepAlive(context.TODO(), resp.ID); err != nil {
+
+	ch, err := n.Client.KeepAlive(context.TODO(), resp.ID)
+	if err != nil {
 		return
 	}
-	n.lID = resp.ID
 
+	n.lID, n.lch = resp.ID, ch
 	return
 }
 
@@ -95,14 +112,16 @@ func (n *Node) Exist() (pid int, err error) {
 		if _, err = n.Client.Delete(ctx, n.Key, client.WithFromKey()); err != nil {
 			return
 		}
+		return -1, nil
 	}
 
 	p, err := os.FindProcess(pid)
 	if err != nil {
-		return
+		return -1, nil
 	}
 
-	if p != nil {
+	// TODO: 暂时不考虑 linux/unix 以外的系统
+	if p != nil && p.Signal(syscall.Signal(0)) == nil {
 		return
 	}
 
@@ -111,11 +130,37 @@ func (n *Node) Exist() (pid int, err error) {
 
 // 启动服务
 func (n *Node) Run() {
+	go n.keepAlive()
+}
 
+// 断网掉线重新注册
+func (n *Node) keepAlive() {
+	for {
+		for _ = range n.lch {
+		}
+
+		select {
+		case <-n.done:
+			return
+		default:
+		}
+		time.Sleep(time.Duration(n.ttl+1) * time.Second)
+
+		log.Noticef("%s has dropped, try to reconnect...", n.String())
+		if err := n.Register(); err != nil {
+			log.Warn(err.Error())
+		} else {
+			log.Noticef("%s reconnected", n.String())
+		}
+	}
 }
 
 // 启动服务
 func (n *Node) Stop(i interface{}) {
-	n.Client.Revoke(context.TODO(), n.lID)
+	close(n.done)
+	// 防止断网时卡住
+	ctx, cancel := context.WithTimeout(context.Background(), 500*time.Millisecond)
+	n.Client.Delete(ctx, n.Key, client.WithFromKey())
+	cancel()
 	n.Client.Close()
 }