Add opt-in auto-update from Gitea releases

The program now lives in /usr/local/lib/blacktip and is owned by its service user so it can replace itself.

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

cmd/blacktip/main.go

@@ -11,6 +11,7 @@ import (
 
 	"git.veillax.com/Veillax/blacktip"
 	"git.veillax.com/Veillax/reef/dotenv"
+	"git.veillax.com/Veillax/reef/selfupdate"
 )
 
 // version is set at build time (deploy/build.sh).
@@ -38,6 +39,7 @@ func main() {
 	acmeDNS := flag.String("acme-dns", os.Getenv("BLACKTIP_ACME_DNS"), "with -traefik: DNS-challenge provider (e.g. cloudflare) for wildcard certificates; its credentials go in this process's environment")
 	noACME := flag.Bool("no-acme", false, "with -traefik: serve Traefik's self-signed certificate instead of requesting Let's Encrypt ones")
 	flag.String("env", ".env", "file to read secrets and settings from")
+	autoUpdate := flag.Bool("auto-update", os.Getenv("BLACKTIP_AUTO_UPDATE") == "1", "check for new releases every few hours and update and restart by itself (Linux and macOS)")
 	showVersion := flag.Bool("version", false, "print the version and exit")
 	flag.Parse()
 	if *showVersion {
@@ -58,6 +60,9 @@ func main() {
 	log.Printf("blacktip %s starting", version)
 	ctx, stop := signal.NotifyContext(context.Background(), os.Interrupt)
 	defer stop()
+	if *autoUpdate {
+		go selfupdate.Run(ctx, selfupdate.Config{Server: "https://git.veillax.com", Repo: "Veillax/blacktip", App: "blacktip", Current: version, Logf: log.Printf})
+	}
 	if err := b.Run(ctx); err != nil {
 		log.Fatal(err)
 	}