init commit

archive/go/hot-restart/main.go

@@ -0,0 +1,113 @@
+package main
+
+import (
+	"context"
+	"flag"
+	"net"
+	"net/http"
+	"os"
+	"os/exec"
+	"os/signal"
+	"sync"
+	"syscall"
+	"time"
+)
+
+// 一个停止的信号量
+var (
+	isStop   bool
+	lock     sync.WaitGroup
+	server   *http.Server
+	listener net.Listener
+	isReload bool
+)
+
+func init() {
+	flag.BoolVar(&isReload, "reload", false, "")
+	flag.Parse()
+}
+
+// 优雅停止中间件
+func GracefulStop(handel func(http.ResponseWriter, *http.Request)) func(http.ResponseWriter, *http.Request) {
+	return func(writer http.ResponseWriter, request *http.Request) {
+		lock.Add(1)
+		if isStop {
+			//不再接收新的请求
+			writer.WriteHeader(400)
+			writer.Write([]byte("server is stop"))
+		} else {
+			handel(writer, request)
+		}
+		lock.Done()
+	}
+}
+
+// 一个会耗时很长的方法
+func LongTime(writer http.ResponseWriter, request *http.Request) {
+	time.Sleep(time.Second * 5)
+	writer.Write([]byte("Hello"))
+}
+
+func Normal(writer http.ResponseWriter, request *http.Request) {
+	writer.Write([]byte("Hello"))
+}
+
+func main() {
+
+	http.HandleFunc("/normal", Normal)
+	http.HandleFunc("/long-time", GracefulStop(LongTime))
+
+	//监听信号
+	go func() {
+		ch := make(chan os.Signal, 1)
+		signal.Notify(ch, syscall.SIGINT, syscall.SIGTERM, syscall.SIGUSR1)
+		for {
+			sign := <-ch
+			ctx, _ := context.WithTimeout(context.Background(), 20*time.Second)
+			switch sign {
+			case syscall.SIGINT, syscall.SIGTERM:
+				{
+					println("stop...")
+					//停止
+					isStop = true
+					lock.Wait()
+					//结束
+					signal.Stop(ch)
+					server.Shutdown(ctx)
+					println("stop")
+					return
+				}
+			case syscall.SIGUSR1:
+				{
+					println("reload...")
+					//热重启
+					tl, _ := listener.(*net.TCPListener)
+					f, _ := tl.File()
+					cmd := exec.Command(os.Args[0], "--reload")
+					cmd.Stdout = os.Stdout
+					cmd.Stdin = os.Stdin
+					cmd.Stderr = os.Stderr
+					cmd.ExtraFiles = []*os.File{f}
+					cmd.Start()
+					signal.Stop(ch)
+					server.Shutdown(ctx)
+					println("father stop")
+					return
+				}
+			}
+		}
+	}()
+	if isReload {
+		f := os.NewFile(3, "")
+		listener, _ = net.FileListener(f)
+		println("child start")
+	} else {
+		listener, _ = net.Listen("tcp", ":8080")
+	}
+	server = &http.Server{
+		Addr:    ":8080",
+		Handler: nil,
+	}
+
+	server.Serve(listener)
+}

archive/go/hot-restart/readme.md

@@ -0,0 +1,14 @@
+# 热重启
+
+可以通过nginx来实现热重启
+
+这里尝试使用fork的方式实现热重启
+
+某些信号量需要linux才有
+
+使用`kill pid `
+
+# 优雅结束
+将请求处理完之后再结束
+
+