78 lines
1.9 KiB
Go
78 lines
1.9 KiB
Go
// Copyright (c) Tailscale Inc & AUTHORS
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// SPDX-License-Identifier: BSD-3-Clause
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//go:build linux
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package systemd
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import (
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"errors"
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"log"
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"os"
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"sync"
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"github.com/mdlayher/sdnotify"
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)
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var getNotifyOnce struct {
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sync.Once
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v *sdnotify.Notifier
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}
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type logOnce struct {
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sync.Once
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}
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func (l *logOnce) logf(format string, args ...any) {
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l.Once.Do(func() {
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log.Printf(format, args...)
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})
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}
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var (
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readyOnce = &logOnce{}
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statusOnce = &logOnce{}
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)
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func notifier() *sdnotify.Notifier {
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getNotifyOnce.Do(func() {
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var err error
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getNotifyOnce.v, err = sdnotify.New()
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// Not exist means probably not running under systemd, so don't log.
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if err != nil && !errors.Is(err, os.ErrNotExist) {
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log.Printf("systemd: systemd-notifier error: %v", err)
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}
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})
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return getNotifyOnce.v
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}
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// Ready signals readiness to systemd. This will unblock service dependents from starting.
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func Ready() {
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err := notifier().Notify(sdnotify.Ready)
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if err != nil {
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readyOnce.logf("systemd: error notifying: %v", err)
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}
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}
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// Status sends a single line status update to systemd so that information shows up
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// in systemctl output. For example:
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//
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// $ systemctl status tailscale
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// ● tailscale.service - Tailscale client daemon
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// Loaded: loaded (/nix/store/qc312qcy907wz80fqrgbbm8a9djafmlg-unit-tailscale.service/tailscale.service; enabled; vendor preset: enabled)
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// Active: active (running) since Tue 2020-11-24 17:54:07 EST; 13h ago
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// Main PID: 26741 (.tailscaled-wra)
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// Status: "Connected; user@host.domain.tld; 100.101.102.103"
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// IP: 0B in, 0B out
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// Tasks: 22 (limit: 4915)
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// Memory: 30.9M
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// CPU: 2min 38.469s
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// CGroup: /system.slice/tailscale.service
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// └─26741 /nix/store/sv6cj4mw2jajm9xkbwj07k29dj30lh0n-tailscale-date.20200727/bin/tailscaled --port 41641
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func Status(format string, args ...any) {
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err := notifier().Notify(sdnotify.Statusf(format, args...))
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if err != nil {
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statusOnce.logf("systemd: error notifying: %v", err)
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}
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}
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