frostfs-node/pkg/util/sdnotify/sdnotify.go

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package sdnotify
import (
"fmt"
"net"
"os"
"strings"
)
const (
ReadyEnabled = "READY=1"
StoppingEnabled = "STOPPING=1"
ReloadingEnabled = "RELOADING=1"
)
var socket *net.UnixAddr
// Initializes socket with provided name of
// environment variable.
func InitSocket() error {
notifySocket := os.Getenv("NOTIFY_SOCKET")
if notifySocket == "" {
return fmt.Errorf("\"NOTIFY_SOCKET\" environment variable is not present")
}
socket = &net.UnixAddr{
Name: notifySocket,
Net: "unixgram",
}
return nil
}
// FlagAndStatus sends systemd a combination of a
// well-known status and STATUS=%s{status}, separated by newline.
func FlagAndStatus(status string) error {
status += "\nSTATUS=" + strings.TrimSuffix(status, "=1")
return Send(status)
}
// Status sends systemd notify STATUS=%s{status}.
func Status(status string) error {
return Send(fmt.Sprintf("STATUS=%s", status))
}
// Send state through the notify socket if any.
// If the notify socket was not detected, it returns an error.
func Send(state string) error {
if socket == nil {
return fmt.Errorf("socket is not initialized")
}
conn, err := net.DialUnix(socket.Net, nil, socket)
if err != nil {
return fmt.Errorf("can't open unix socket: %v", err)
}
defer conn.Close()
if _, err = conn.Write([]byte(state)); err != nil {
return fmt.Errorf("can't write into the unix socket: %v", err)
}
return nil
}