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// +build linux darwin freebsd
package utils
import (
"errors"
"fmt"
"net"
"os"
"strings"
"syscall"
"github.com/valyala/tcplisten"
)
// CreateListener crates socket listener based on DSN definition.
func CreateListener(address string) (net.Listener, error) {
dsn := strings.Split(address, "://")
if len(dsn) != 2 {
return nil, errors.New("invalid DSN (tcp://:6001, unix://file.sock)")
}
if dsn[0] != "unix" && dsn[0] != "tcp" {
return nil, errors.New("invalid Protocol (tcp://:6001, unix://file.sock)")
}
// create unix listener
if dsn[0] == "unix" {
// check if the file exist
if fileExists(dsn[1]) {
err := syscall.Unlink(dsn[1])
if err != nil {
return nil, fmt.Errorf("error during the unlink syscall: error %v", err)
}
}
return net.Listen(dsn[0], dsn[1])
}
// configure and create tcp4 listener
cfg := tcplisten.Config{
ReusePort: true,
DeferAccept: true,
FastOpen: true,
Backlog: 0,
}
// only tcp4 is currently supported
return cfg.NewListener("tcp4", dsn[1])
}
// fileExists checks if a file exists and is not a directory before we
// try using it to prevent further errors.
func fileExists(filename string) bool {
info, err := os.Stat(filename)
if os.IsNotExist(err) {
return false
}
return !info.IsDir()
}
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