在Golang中执行net.DialTCP时如何设置超时时间？

Question

net.DialTCP 似乎是获取net.TCPConn的唯一办法，我不确定在执行 DialTCP时如何设置超时。

func connectAddress(addr *net.TCPAddr, wg *sync.WaitGroup) error {
    start := time.Now()
    conn, err := net.DialTCP("tcp", nil, addr)
    if err != nil {
        log.Printf("Dial failed for address: %s, err: %s", addr.String(), err.Error())
        return err
    }
    elasped := time.Since(start)
    log.Printf("Connected to address: %s in %dms", addr.String(), elasped.Nanoseconds()/1000000)
    conn.Close()
    wg.Done()
    return nil
}

Answer 1

Use net.Dialer with either the Timeout or Deadline fields set.

d := net.Dialer{Timeout: timeout}
conn, err := d.Dial("tcp", addr)
if err != nil {
   // handle error
}

A variation is to call Dialer.DialContext with a deadline or timeout applied to the context.

Type assert to *net.TCPConn if you specifically need that type instead of a net.Conn:

tcpConn, ok := conn.(*net.TCPConn)