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// +build linux darwin freebsd
package utils
import (
"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, "://")
switch len(dsn) {
case 1:
// assume, that there is no prefix here [127.0.0.1:8000]
return createTCPListener(dsn[0])
case 2:
// we got two part here, first part is the transport, second - address
// [tcp://127.0.0.1:8000] OR [unix:///path/to/unix.socket] OR [error://path]
// where error is wrong transport name
switch dsn[0] {
case "unix":
// check of file exist. If exist, unlink
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])
case "tcp":
return createTCPListener(dsn[1])
// not an tcp or unix
default:
return nil, fmt.Errorf("invalid Protocol ([tcp://]:6001, unix://file.sock), address: %s", address)
}
// wrong number of split parts
default:
return nil, fmt.Errorf("wrong number of parsed protocol parts, address: %s", address)
}
}
func createTCPListener(addr string) (net.Listener, error) {
cfg := tcplisten.Config{
ReusePort: true,
DeferAccept: true,
FastOpen: true,
Backlog: 0,
}
listener, err := cfg.NewListener("tcp4", addr)
if err != nil {
return nil, err
}
return listener, nil
}
// 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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