82 lines
2.3 KiB
Go
82 lines
2.3 KiB
Go
package sdnotify
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import (
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"errors"
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"fmt"
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"net"
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"os"
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"strings"
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"time"
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)
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const (
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ReadyEnabled = "READY=1"
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StoppingEnabled = "STOPPING=1"
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ReloadingEnabled = "RELOADING=1"
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)
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var (
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socket *net.UnixAddr
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start = time.Now()
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errSocketVariableIsNotPresent = errors.New("\"NOTIFY_SOCKET\" environment variable is not present")
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errSocketIsNotInitialized = errors.New("socket is not initialized")
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)
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// Initializes socket with provided name of
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// environment variable.
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func InitSocket() error {
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notifySocket := os.Getenv("NOTIFY_SOCKET")
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if notifySocket == "" {
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return errSocketVariableIsNotPresent
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}
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socket = &net.UnixAddr{
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Name: notifySocket,
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Net: "unixgram",
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}
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return nil
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}
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// FlagAndStatus sends systemd a combination of a
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// well-known status and STATUS=%s{status}, separated by newline.
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func FlagAndStatus(status string) error {
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if status == ReloadingEnabled {
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// From https://www.man7.org/linux/man-pages/man5/systemd.service.5.html
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//
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// When initiating the reload process the service is
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// expected to reply with a notification message via
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// sd_notify(3) that contains the "RELOADING=1" field in
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// combination with "MONOTONIC_USEC=" set to the current
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// monotonic time (i.e. CLOCK_MONOTONIC in
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// clock_gettime(2)) in μs, formatted as decimal string.
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// Once reloading is complete another notification message
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// must be sent, containing "READY=1".
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//
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// For MONOTONIC_USEC format refer to https://www.man7.org/linux/man-pages/man3/sd_notify.3.html
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status += fmt.Sprintf("\nMONOTONIC_USEC=%d", uint64(time.Since(start))/1e3 /* microseconds in nanoseconds */)
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}
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status += "\nSTATUS=" + strings.TrimSuffix(status, "=1")
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return Send(status)
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}
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// Status sends systemd notify STATUS=%s{status}.
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func Status(status string) error {
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return Send("STATUS=" + status)
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}
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// Send state through the notify socket if any.
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// If the notify socket was not detected, it returns an error.
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func Send(state string) error {
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if socket == nil {
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return errSocketIsNotInitialized
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}
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conn, err := net.DialUnix(socket.Net, nil, socket)
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if err != nil {
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return fmt.Errorf("can't open unix socket: %v", err)
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}
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defer conn.Close()
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if _, err = conn.Write([]byte(state)); err != nil {
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return fmt.Errorf("can't write into the unix socket: %v", err)
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}
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return nil
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}
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