go bidirectional copying

gistfile1.go

func BidirectionalCopy(conn net.Conn, channel net.Conn) {
    
    start := time.Now()

    var done = make(chan int, 1)
    go copy("to ssh channel", conn, channel, done)
    go copy("from ssh channel", channel, conn, done)
    written := <-done
    conn.Close()
    channel.Close()
    written += <-done

    seconds := time.Since(start).Seconds()
    p := float64(written) / seconds / 1024 / 1024
    nlog.WRN("transferred %d byte: %v: %.2f MByte/sec", written, time.Since(start), p)
}


func copy(label string, src io.Reader, dest io.Writer, done chan int) {
    buf := make([]byte, 1024 * 16)

    var written int
    var err error
    
    for {
        var bytes int
        bytes, err = src.Read(buf)
        if err == nil {
            bytes, err = dest.Write(buf[:bytes])
        }
        if err != nil {
            break
        }
        
        nlog.DBG("%s: transferred %d bytes", label, bytes)
        written += bytes
    }

    if err != io.EOF && strings.Index(err.Error(), "use of closed network connection") == -1 {
        nlog.INF("copied %d byte %s before failing w/%v", written, label, err)
    } else {
        nlog.INF("copied %d byte %s", written, label)
    }
    done <- written
}