Simple terminal GUI LXC container manager

manage_containers.lua

#!/usr/bin/env lua5.1
--[[
This file provides a simple menu for managing LXC containers
by calling the associated lxc-* programms.
It uses the dialog util to provide interactive menus.

Currently, it supports:
 * create/start/stop/delete/clone/rename containers
 * list running/stopped containers
 * show info/statistics about container
 * create root filesystem tarball backup
]]
local function quote(str)
	str = tostring(str)
	return "\""..str:gsub("%c", function(char)
		if char == "\n" then
			return "\\n"
		end
		return "\\"..char:byte()
	end).."\""
end

function trim(str)
	return (str:gsub("^%s*(.-)%s*$", "%1"))
end

local function exec(cmd)
	return os.execute(cmd)
end


local confirm_mode = 0.5 --"confirm"/timeout/nil
local function lxc_confirm(cmd)
	print("LXC command:", cmd)
	if confirm_mode == "confirm" then
		print("Press enter to confirm, ^c to abort")
		io.read("*l")
	elseif tonumber(confirm_mode) then
		print("(abort using ^c)")
		exec("sleep " .. tonumber(confirm_mode))
	end
	print("running...")
end
local function lxc_exec(cmd)
	lxc_confirm(cmd)
	return exec(cmd)
end
local function lxc_popen(cmd)
	lxc_confirm(cmd)
	return io.popen(cmd)
end

local function dialog_exec(cmd)
	local ret = exec("dialog --backtitle \"Manage LXC containers\" "..cmd)
end

local function dialog_popen(cmd)
	return io.popen("dialog --stdout --backtitle \"Manage LXC containers\" "..cmd)
end

local function show_menu(title, list)
	local cmd = ("--menu %s 0 0 0 "):format(quote(title))
	for k,v in ipairs(list) do
		cmd = cmd .. quote(v[1]) .. " " .. quote(v[2])
		if k~= #list then
			cmd = cmd .. " "
		end
	end
	local p = dialog_popen(cmd)
	local data = p:read("*a")
	if data and data ~= "" then
		return data
	end
end

local function msgbox(text)
	local cmd = ("--msgbox %s 0 0"):format(quote(text))
	dialog_exec(cmd)
end

local function text_input(prompt, init)
	local p = dialog_popen(("--inputbox %s 0 0 %s"):format(quote(prompt), init or ""))
	return p:read("*a")
end

local function get_container_info(container)
	local f = lxc_popen("lxc-info -n " .. quote(container))
	local container_info = {}
	for line in f:lines() do
		local k,v = line:match("^(.*):(.*)$")
		assert(k and v, "info match failed: \"" .. line .. "\"")
		k,v = trim(k), trim(v)
		container_info[k] = v
	end
	return container_info
end

local function get_container_list()
	local f = lxc_popen("lxc-ls -1 --active")
	local active = {}
	for line in f:lines() do
		table.insert(active, line)
	end
	f = lxc_popen("lxc-ls -1 --stopped")
	local stopped = {}
	for line in f:lines() do
		table.insert(stopped, line)
	end
	return active,stopped
end

local function show_container_info(container)
	local container_info = get_container_info(container)
		local info_str = ([[
Name: %s
State: %s
IP: %s
Link: %s
PID: %s

CPU use: %s
Memory use: %s

BlkIO use: %s
KMem use: %s
RX bytes: %s
TX bytes: %s
]]):format(
		assert(container_info["Name"]),
		assert(container_info["State"]),
		assert(container_info["IP"] or "none"),
		assert(container_info["Link"] or "none"),
		assert(container_info["PID"] or "none"),
		assert(container_info["CPU use"] or "none"),
		assert(container_info["Memory use"] or "none"),
		assert(container_info["BlkIO use"] or "none"),
		assert(container_info["KMem use"] or "none"),
		assert(container_info["RX bytes"] or "none"),
		assert(container_info["TX bytes"] or "none")
	)
	msgbox(info_str)
end

local function menu_stopped_container(container)
	local menu = {
		{"info", "Show container information"},
		{"edit", "Edit container configuration"},
		{"start", "Start the container"},
		{"create_tar", "Create a tarball backup of the container root filesystem"},
		{"destroy", "Destroy the container"},
		{"clone", "Clone the container"},
		{"rename", "Rename the container"},
	}
	repeat
		local selected = show_menu("Container " .. container, menu)
		if selected == "info" then
			show_container_info(container)
		elseif selected == "edit" then
			exec("nano /var/lib/lxc/" .. container .. "/config")
		elseif selected == "start" then
			lxc_exec("lxc-start -n " .. quote(container))
			break
		elseif selected == "create_tar" then
			lxc_exec("lxc-execute -n " .. container .. " -- /bin/sh -c \"tar -vc --xattrs -S -f /tmp/backup.tar --exclude=/dev --exclude=/tmp --exclude=/run --exclude=/proc --exclude=/sys /\"")
			local backup_name = ("backup_%s_%s.tar"):format(container, os.date("%d_%m_%Y-%H_%M_%S"))
			lxc_exec("lxc-execute -n " .. container .. " -- /bin/sh -c \"cat /tmp/backup.tar\" > " .. backup_name)
		elseif selected == "destroy" then
			local input_name = text_input("This can not be undone.\nPlease type the container name to confirm deleting it")
			assert(container==input_name)
			lxc_exec("lxc-destroy -n " .. container)
			break
		elseif selected == "clone" then
			local new_name = text_input("Please enter a name for the new container:")
			lxc_exec("lxc-copy -n " .. container .. " -N " .. new_name)
		elseif selected == "rename" then
			local new_name = text_input("Please enter the new name for the new container:")
			lxc_exec("lxc-copy -R -n " .. container .. " -N " .. new_name)
			break
		else
			break
		end
	until not selected
end

local function menu_running_container(container)
	local menu = {
		{"info", "Show container information"},
		{"shell", "Get a shell in this container"},
		{"console", "Get a console in this container"},
		{"stop", "Stop the container"},
	}
	repeat
		local selected = show_menu("Container "..container, menu)
		if selected == "info" then
			show_container_info(container)
		elseif selected == "shell" then
			lxc_exec("lxc-attach -n " .. container .. " /bin/bash")
		elseif selected == "console" then
			lxc_exec("lxc-console -t 0 -n " .. container)
		elseif selected == "stop" then
			lxc_exec("lxc-stop -n " .. container)
			break
		end
	until not selected
	--menu_running_container(container)
end

local function menu_running()
	local menu = {}
	local active = get_container_list()
	if #active == 0 then
		return msgbox("No running containers!")
	end
	for k,v in ipairs(active) do
		table.insert(menu, {tostring(k),tostring(v)})
	end
	local selected = show_menu("Running containers", menu)
	if tonumber(selected) then
		return menu_running_container(active[tonumber(selected)])
	end
end

local function menu_stopped()
	local menu = {}
	local _,stopped = get_container_list()
	if #stopped == 0 then
		return msgbox("No stopped containers!")
	end
	for k,v in ipairs(stopped) do
		table.insert(menu, {tostring(k),tostring(v)})
	end
	local selected = show_menu("Stopped containers", menu)
	if tonumber(selected) then
		return menu_stopped_container(stopped[tonumber(selected)])
	end
end

local function menu_create()
	local container_name = text_input("Please enter a name for the new container:")
	assert(container_name and container_name~="")
	assert(container_name:match("^[a-zA-Z-_0-9]+$"))
	local default_template = "debian"
	local template = text_input("Enter the template to use\nDefault: " .. default_template .. "")
	if not template or template=="" then
		template = default_template
	end
	local default_template_options = "-r stable"
	local template_options = text_input("Enter template options\nDefault: "..default_template_options)
	if not template_options or template_options=="" then
		template_options = default_template_options
	end
	lxc_exec("lxc-create -n " .. container_name .. " -t " .. template .. " -- " .. template_options)
	io.read()
end

local function menu_main()
	local menu = {
		{"running", "Manage running contaners"},
		{"stopped", "Manage stopped contaners"},
		{"create", "Create a new container"},
		{"clone", "Clone a container"},
	}
	repeat
		local selected = show_menu("Main menu", menu)
		if selected == "running" then
			menu_running()
		elseif selected == "stopped" then
			menu_stopped()
		elseif selected == "create" then
			menu_create()
		elseif selected == "noconfirm" then
			msgbox("No further confirm dialogs will be shown!")
			confirm_mode = nil
		elseif selected == "timeout" then
			msgbox("Will show command abort messge for 3 seconds!")
			confirm_mode = 3
		elseif selected == "confirm" then
			msgbox("Will require command confirm for every LXC command!")
			confirm_mode = "confirm"
		end
	until not selected

end

menu_main()