wlsleephandler-rs - Wayland SleepHandler

This is intended as a replacement of sway's idle management daemon. I use it as a tool to understand rust message passing and state management. It aims to have the following goals:

• automatic setup of xdg config folder
• lua scripting to define idle management with a lua config
• automatic script reloading
• handling of AC and battery based idle timeouts
• screen locking with systemd locking

I am now using it as a replacement for any ac and battery power daemon, since I can run tasks with it.

Install

Until packaging is added you can install sleepwatcher using cargo.

cargo install --git https://github.com/fishman/sleepwatcher-rs

Debug

sleepwatcher-rs uses env_logger. You can enable logging by setting the RUST_LOG environment variable:

RUST_LOG=debug sleepwatcher-rs

Default config

The default config is written to ~/.config/sleepwatcher-rs/idle_config.lua on startup if the folder and file does not exist yet.

Syntax

Lua is configured to be sandboxed, so no library functions can be used and only functions exposed inside the Rust can be used.

Important distinction between Helpers:run and Helpers:run_once. run_once will check if a process of that name is already running and won't spawn a new one in that case. This may be useful, when a screen locker can create race conditions if spawned twice.

Originally I wanted to reload the config whenever the AC adaptor is plugged in and out, but due to the timeout issue described below, you can check for the on_battery state in functions.

Helpers:log("Loading idle_config.lua")

function LockScreen()
  Helpers:log("Locking Screen")
  IdleNotifier:run_once("swaylock -f")
end

function ScreenLockBattery(event)
  if event == "idled" and Helpers:on_battery() then
    LockScreen()
  end
end

DbusHandler:PrepareSleep("LockScreen")
DbusHandler:LockHandler("LockHandler")
DbusHandler:UnlockHandler("UnlockHandler")
IdleNotifier:get_notification(300,  "ScreenLockBattery")

get_notification creates a Wayland idle timeout handler. It uses the ext-idle-notify-v1 protocol. It is not (yet) possible to create callback functions, so the function calls are made by specifying the name of the function.

PrepareSleep, LockScreen, UnlockScreen, are dbus signals from the org.freedesktop.logind.manager and org.freedesktop.logind.session.

Known issues

• sleepwatcher-rs should automatically reload the config when ~/.config/sleepwatcher-rs/idle_config.lua is changed. However, due to an unknown reason the first trigger after reload still follows the old timeout and the next trigger is therefore equal to the rest of the previous timeout+the new timeout setting.

TODOS

• build CI
• AUR package
• use more idiomatic lua syntax
• add tests
• enable callbacks for lua code. it currently complains about lua functions not supporting Send. It's related to the way the user methods are implemented
• duplicate state information
• find a way to remove the std::thread::spawn that used within the lua thread to run_once
• add idle hints
• improve return and error handling
• turn wayland_run spawn_blocking into async