golang http 服务器在信号后正常关闭

Question

我正在尝试编写代码，在收到信号时优雅地关闭 http 服务器。

我的代码有两个 go 例程 - signalHandler() 和 simpleServiceStarter() - 一个用于信号处理，另一个用于 http 服务器。收到信号后，处理程序应关闭 http 服务器所以 simpleServiceStarter() 从 ListenAndServe() 中断。下面是我的代码。

package main

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

var (
    simpleHTTPServer      http.Server
    sigChan               chan os.Signal
    simpleServiceShutdown chan bool
)

func simpleServiceStarter() {
    mux := http.NewServeMux()
    simpleHTTPServer := &http.Server{
        Addr:           ":9000",
        Handler:        mux,
        ReadTimeout:    10 * time.Second,
        WriteTimeout:   10 * time.Second,
        MaxHeaderBytes: 1 << 20,
    }
    fmt.Printf("\nstarting http server on :9000 ")
    err := simpleHTTPServer.ListenAndServe()
    if err != http.ErrServerClosed {
        fmt.Printf("error starting simple service or closing listener - %v\n", err)
    }
    fmt.Printf("simple service http server shutdown completed - %v\n", err)

    // communicate with main thread
    simpleServiceShutdown <- true
}

func signalHandler() {
    // Handle SIGINT and SIGHUP.
    signal.Notify(sigChan, syscall.SIGINT, syscall.SIGHUP)

    sig := <-sigChan
    fmt.Printf("\nsignalHandler() received signal: %v\n", sig)

    // gracefully shutdown http server
    err := simpleHTTPServer.Shutdown(context.Background())
    fmt.Printf("simple service shutdown on signal %v, error: %v\n", sig, err)
    close(sigChan)

}

func main() {
    // block all async signals to this server. And we register only SIGINT and SIGHUP for now.
    signal.Ignore()

    sigChan = make(chan os.Signal, 1)
    simpleServiceShutdown = make(chan bool)
    go signalHandler()

    go simpleServiceStarter()
    <-simpleServiceShutdown // wait server to shutdown
    close(simpleServiceShutdown)
}

发送信号后，服务器没有中断，还在等待。

Run the program as:
$ ./simpleHttp 

starting http server on :9000 
signalHandler() received signal: interrupt
simple service shutdown on signal interrupt, error: <nil>
$

From another terminal send the signal as:
tester 30202  4379  0 09:14 pts/8    00:00:00 ./simpleHttp
kill -s SIGINT 30202

我正在使用 go1.12.6 linux/amd64。

Answer 1

在 func simpleServiceStarter() 中声明局部 simpleHTTPServer := &http.Server which shadow global

var (
    simpleHTTPServer      http.Server

不能在 func simpleServiceStarter() 范围之外引用此局部变量。只需在 func simpleServiceStarter()

中执行 simpleHTTPServer = &http.Server(无冒号)