在退出http服务的时候,可能要等待后台的某一个协程完成。此时,需要这样:
go的信号处理很巧妙,用的是chan转发。 这是一个官方示例:
package main
import "fmt"
import "os"
import "os/signal"
import "syscall"
func main() {
// Go signal notification works by sending `os.Signal`
// values on a channel. We'll create a channel to
// receive these notifications (we'll also make one to
// notify us when the program can exit).
sigs := make(chan os.Signal, 1)
done := make(chan bool, 1)
// `signal.Notify` registers the given channel to
// receive notifications of the specified signals.
signal.Notify(sigs, syscall.SIGINT, syscall.SIGTERM)
// This goroutine executes a blocking receive for
// signals. When it gets one it'll print it out
// and then notify the program that it can finish.
go func() {
sig := <-sigs
fmt.Println()
fmt.Println(sig)
done <- true
}()
// The program will wait here until it gets the
// expected signal (as indicated by the goroutine
// above sending a value on `done`) and then exit.
fmt.Println("awaiting signal")
<-done
fmt.Println("exiting")
}
此外,server.ListenAndServe()不能跑在main中,因为在main中,要处理其它任务。如何使main阻塞呢?上段代码done这个协程是能派上用场的。 示例代码如下:
https://stackoverflow.com/questions/39320025/how-to-stop-http-listenandserve
package main
import (
"log"
"io"
"time"
"net/http"
)
func startHttpServer() *http.Server {
srv := &http.Server{Addr: ":8080"}
http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
io.WriteString(w, "hello world\n")
})
go func() {
if err := srv.ListenAndServe(); err != nil {
// cannot panic, because this probably is an intentional close
log.Printf("Httpserver: ListenAndServe() error: %s", err)
}
}()
// returning reference so caller can call Shutdown()
return srv
}
func main() {
log.Printf("main: starting HTTP server")
srv := startHttpServer()
log.Printf("main: serving for 10 seconds")
time.Sleep(10 * time.Second)
log.Printf("main: stopping HTTP server")
// now close the server gracefully ("shutdown")
// timeout could be given instead of nil as a https://golang.org/pkg/context/
if err := srv.Shutdown(nil); err != nil {
panic(err) // failure/timeout shutting down the server gracefully
}
log.Printf("main: done. exiting")
}
将这两段代码整合下,相信就很简单了。