LyTop

LyTop is a terminal-based, htop-like system monitor for Linux, designed to be lightweight, extensible, and scriptable. It provides a live overview of memory usage and active processes and supports user-defined widgets through Lua.

Features

• Memory Usage Bar
  Displays RAM usage with multiple colored segments:

  • Green: Used memory
  • Yellow: Cached memory

• Process Table
  Dynamically shows active processes sorted by memory use.

• Overlay Widgets
  Toggleable help and debug boxes rendered directly in the UI.

• Keybindings

  • j/k: Scroll process list
  • a: Toggle kernel processes
  • h: Toggle help overlay
  • d: Toggle debug overlay
  • q: Quit

Build Instructions

Requirements

• A C++20-compatible compiler (GCC or Clang)
• Lua 5.4
• A POSIX-compatible terminal (Linux/macOS)

Build & Run

Clone the repository and build:

git clone -b --recurse-submodules stable https://github.com/HasSak-47/monitor.git
cd monitor
make build      # Build the application
make run        # Run the default demo

Lua Scripting API

Lytop is designed for Lua-driven customization. The entire interface—including widgets, rendering, and user input—is controlled from a Lua script.

Widget Architecture

Widgets follow a simple inheritance model using metatables. Each widget can implement:

• :new() – Constructor
• :render(buffer) – Draw the widget
• :update() – Optional, for dynamic state

Example: A Custom Bar Widget

local Bar = widget:extend({
    new = function(self)
        local t = self.super.new(self)
        setmetatable(t, self)
        t._type = "Bar"
        t.percentage = 0.5
        return t
    end,

    render = function(self, buffer)
        local x, _ = buffer:get_size()
        buffer:set(1, 1, '[')
        buffer:set(x, 1, ']')
        for i = 1, math.floor((x - 2) * self.percentage) do
            buffer:set(i + 1, 1, '|', { type = "bit", R = 1, G = 0, B = 0 })
        end
    end
})

Provided Widgets

• Bar – Simple single-value progress bar
• MultiBar – Composite memory bar with multiple values/colors
• Box – Draws a border around another widget
• DebugData, HelpData – Optional overlays showing internal state or usage hints
• M_type – Default UI layout: renders memory usage and process table, handles input

Memory Format Helpers

Memory values are automatically humanized using base-1024 formatting (e.g., 512MB, 2.1GB).

Extending Lytop

To create a new layout or behavior:

• Edit init.lua (or your custom script)
• Add or modify widgets using the provided API
• Use state to access system data (fps, tick, offset, processes, etc.)
• Use state.on_event to bind keys