golang如何优雅处理退出

有时候我们想在Go程序中处理Signal信号，比如收到SIGTERM信号后优雅的关闭程序(参看下一节的应用)。
Go信号通知机制可以通过往一个channel中发送os.Signal实现。

首先我们创建一个os.Signal channel，然后使用signal.Notify注册要接收的信号。

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")
}

go run main.go执行这个程序，敲入ctrl-C会发送SIGINT信号。 此程序接收到这个信号后会打印退出。

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