circolog/cmd/circologd/sockets.go

package main

import (
	"net"
)

// SyslogSocket is a struct eventually containing a net.Listener
// ready with messages, and a Path in case the Listener is not present.
type SyslogSocket struct {
	Listener          net.Listener
	Conn              net.PacketConn
	Path              string
	isSocketActivated bool
}

// Set from command-line
func (s *SyslogSocket) Set(v string) error {
	err := s.getActivationSocket()
	if err == nil && (s.Conn != nil || s.Listener != nil) {
		s.isSocketActivated = true
	}
	if !s.isSocketActivated {
		s.Path = v
	}
	return nil
}

func (s *SyslogSocket) String() string {
	if s.isSocketActivated {
		return "systemd-provided"
	}
	return s.Path
}

func (s *SyslogSocket) getActivationSocket() error {
	conns, err := PacketConns()
	if err == nil && len(conns) > 0 && conns[0] != nil {
		s.Conn = conns[0]
		return nil
	}
	listeners, err := Listeners()
	if err != nil {
		return err
	}
	if len(listeners) == 0 {
		return nil
	}
	s.Listener = listeners[0]
	return nil
}