Go后端发布拓扑发布回滚与故障恢复 - 第2节

• 部署简单，运维成本最低
• 存在单点故障（SPOF），进程崩溃即服务中断
• 发布期间必须停机更新，无法做到零停机
• 回滚操作直接替换二进制或镜像，速度最快

// main.go
package main

import (
    "context"
    "net/http"
    "os"
    "os/signal"
    "syscall"
    "time"
)

func healthzHandler(w http.ResponseWriter, r *http.Request) {
    w.WriteHeader(http.StatusOK)
    w.Write([]byte("ok"))
}

func readyzHandler(w http.ResponseWriter, r *http.Request) {
    // 检查数据库连接、缓存等依赖
    if dbReady() && cacheReady() {
        w.WriteHeader(http.StatusOK)
        w.Write([]byte("ready"))
        return
    }
    w.WriteHeader(http.StatusServiceUnavailable)
}

func main() {
    mux := http.NewServeMux()
    mux.HandleFunc("/healthz", healthzHandler)
    mux.HandleFunc("/readyz", readyzHandler)
    // 业务路由...

    srv := &http.Server{Addr: ":8080", Handler: mux}

    // 优雅启停
    go func() {
        sigCh := make(chan os.Signal, 1)
        signal.Notify(sigCh, syscall.SIGINT, syscall.SIGTERM)
        <-sigCh
        ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
        defer cancel()
        srv.Shutdown(ctx)
    }()

    srv.ListenAndServe()
}