optimize discord command registration for faster startup and shutdown

cmd/themis-server/main.go

@@ -37,6 +37,9 @@ var (
 type Handler func(s *discordgo.Session, i *discordgo.InteractionCreate)
 
 func main() {
+	log.Info().Msg("startup.")
+	start := time.Now()
+
 	ctx, cancel := signal.NotifyContext(context.Background(), syscall.SIGTERM, syscall.SIGKILL, syscall.SIGINT)
 	defer cancel()
 
@@ -47,8 +50,7 @@ func main() {
 		zerolog.SetGlobalLevel(zerolog.DebugLevel)
 	}
 	log.Logger = log.Output(zerolog.ConsoleWriter{Out: os.Stdout})
-
-	log.Info().Msg("startup.")
+	zerolog.DurationFieldUnit = time.Millisecond
 
 	go func() {
 		if err := serve(":8080"); err != nil {
@@ -632,19 +634,12 @@ func main() {
 	}
 	defer discord.Close()
 
-	total := len(commands)
-	registeredCommands := make([]*discordgo.ApplicationCommand, total)
-	log.Debug().Int("total", total).Msg("registering commands with Discord")
-	for i, c := range commands {
-		log.Debug().Msg(fmt.Sprintf("registering command %d of %d", i+1, total))
-		command, err := discord.ApplicationCommandCreate(appId, guildId, c)
+	log.Debug().Int("count", len(commands)).Msg("registering commands via bulk overwrite")
+	created, err := discord.ApplicationCommandBulkOverwrite(appId, guildId, commands)
 	if err != nil {
-			log.Fatal().Err(err).Msg("failed to register command")
-		}
-		registeredCommands[i] = command
+		log.Fatal().Err(err).Msg("failed to register commands with discord")
 	}
-
-	log.Info().Int("count", len(registeredCommands)).Msg("registered commands")
+	log.Info().Int("count", len(created)).Dur("startup_latency_ms", time.Since(start)).Msg("registered commands, ready to operate")
 
 	go notifier.NotifyFunc(ctx, func() {
 		log.Info().Msg("sending weekly reminder")
@@ -674,16 +669,6 @@ func main() {
 
 	<-ctx.Done()
 	log.Info().Msg("context cancelled, exiting")
-
-	log.Debug().Int("total", total).Msg("deregistering commands with Discord")
-	for i, c := range registeredCommands {
-		log.Debug().Msg(fmt.Sprintf("registering command %d of %d", i+1, total))
-		err = discord.ApplicationCommandDelete(appId, guildId, c.ID)
-		if err != nil {
-			log.Error().Err(err).Msg("failed to deregister commands")
-		}
-	}
-	log.Info().Msg("deregistered commands, exiting")
 	os.Exit(0)
 }