luci-app-statistics: rewrite stat-genconfig in ucode

Rewrite the collectd config generator script in ucode to remove the implicit
dependency on the Lua runtime.

Also move the stat-genconfig script into /usr/libexec as it isn't really a
user facing executable.

Signed-off-by: Jo-Philipp Wich <jo@mein.io>

4 files changed, 285 insertions, 325 deletions

diff --git a/applications/luci-app-statistics/Makefile b/applications/luci-app-statistics/Makefile
index d2af8abc01..140c136d5b 100644
--- a/applications/luci-app-statistics/Makefile
+++ b/applications/luci-app-statistics/Makefile
@@ -9,7 +9,6 @@ include $(TOPDIR)/rules.mk
 LUCI_TITLE:=LuCI Statistics Application
 LUCI_DEPENDS:= \
 	+luci-base \
-	+luci-lib-jsonc \
 	+collectd \
 	+rrdtool1 \
 	+collectd-mod-rrdtool \
diff --git a/applications/luci-app-statistics/root/etc/init.d/luci_statistics b/applications/luci-app-statistics/root/etc/init.d/luci_statistics
index 2dc176c83c..3684bc1834 100755
--- a/applications/luci-app-statistics/root/etc/init.d/luci_statistics
+++ b/applications/luci-app-statistics/root/etc/init.d/luci_statistics
@@ -17,7 +17,7 @@ start_service() {
 	fi
 
 	### create config
-	/usr/bin/stat-genconfig > /var/etc/collectd.conf
+	/usr/libexec/stat-genconfig > /var/etc/collectd.conf
 
 	### workaround broken permissions on /tmp
 	chmod 1777 /tmp
diff --git a/applications/luci-app-statistics/root/usr/bin/stat-genconfig b/applications/luci-app-statistics/root/usr/bin/stat-genconfig
deleted file mode 100755
index 15e11e193e..0000000000
--- a/applications/luci-app-statistics/root/usr/bin/stat-genconfig
+++ /dev/null
@@ -1,323 +0,0 @@
-#!/usr/bin/lua
-
---[[
-
-Luci statistics - collectd configuration generator
-(c) 2008 Freifunk Leipzig / Jo-Philipp Wich <jow@openwrt.org>
-
-Licensed under the Apache License, Version 2.0 (the "License");
-you may not use this file except in compliance with the License.
-You may obtain a copy of the License at
-
-		http://www.apache.org/licenses/LICENSE-2.0
-
-$Id$
-
-]]--
-
-
-require("luci.model.uci")
-require("luci.util")
-require("luci.i18n")
-require("luci.jsonc")
-require("nixio.fs")
-
-local uci = luci.model.uci.cursor()
-local sections = uci:get_all( "luci_statistics" )
-
-
-function print(...)
-	nixio.stdout:write(...)
-	nixio.stdout:write("\n")
-end
-
-function section( plugin )
-
-	local config = sections[ "collectd_" .. plugin ] or sections["collectd"]
-
-	if type(config) == "table" and ( plugin == "collectd" or config.enable == "1" ) then
-
-		local params = ""
-
-		if type( plugins[plugin] ) == "function" then
-			params = plugins[plugin]( config )
-		else
-			params = config_generic( config, plugins[plugin][1], plugins[plugin][2], plugins[plugin][3], plugin == "collectd" )
-		end
-
-
-		if plugin ~= "collectd" then
-			print( "LoadPlugin " .. plugin )
-
-			if params:len() > 0 then
-				print( "<Plugin " .. plugin .. ">\n" .. params .. "</Plugin>\n" )
-			else
-				print( "" )
-			end
-		else
-			print( params .. "\n" )
-		end
-	end
-end
-
-function config_generic( c, singles, bools, lists, nopad )
-	local str = ""
-
-	if type(c) == "table" then
-
-		if type(singles) == "table" then
-			for i, key in ipairs( singles ) do
-				if preprocess[key] then
-					c[key] = preprocess[key](c[key])
-				end
-
-				str = str .. _string( c[key], key, nopad )
-			end
-		end
-
-		if type(bools) == "table" then
-			for i, key in ipairs( bools ) do
-				if preprocess[key] then
-					c[key] = preprocess[key](c[key])
-				end
-
-				str = str .. _bool( c[key], key, nopad )
-			end
-		end
-
-		if type(lists) == "table" then
-			str = str .. _list_expand( c, lists, nopad )
-		end
-	end
-
-	return str
-end
-
-function config_exec( c )
-	local str = ""
-
-	for s in pairs(sections) do
-		for key, type in pairs({ Exec="collectd_exec_input", NotificationExec="collectd_exec_notify" }) do
-			if sections[s][".type"] == type then
-
-				cmd = sections[s].cmdline
-
-				if cmd then
-					cmd   = cmd:gsub("^%s+", ""):gsub("%s+$", "")
-					user  = sections[s].cmduser  or "nobody"
-					group = sections[s].cmdgroup
-
-					str = str .. "\t" .. key .. ' "' ..
-						user .. ( group and ":" .. group or "" ) .. '" "' ..
-						cmd:gsub('%s+', '" "') .. '"\n'
-				end
-			end
-		end
-	end
-
-	return str
-end
-
-function config_curl( c )
-	local str = ""
-
-	for s in pairs(sections) do
-		if sections[s][".type"] == "collectd_curl_page" then
-			str = str .. "\t<Page \"" .. sections[s].name .. "\">\n" ..
-						 "\t\tURL \"" .. sections[s].url .. "\"\n" ..
-						 "\t\tMeasureResponseTime true\n" ..
-						 "\t</Page>\n"
-		end
-	end
-
-	return str
-end
-
-function config_iptables( c )
-	local str = ""
-
-	for id, s in pairs(sections) do
-		if s[".type"] == "collectd_iptables_match" or s[".type"] == "collectd_iptables_match6" then
-			local tname = s.table and tostring(s.table)
-			local chain = s.chain and tostring(s.chain)
-
-			if tname and tname:match("^%S+$") and chain and chain:match("^%S+$") then
-				local line = { #s[".type"] > 23 and "\tChain6" or "\tChain", tname, chain }
-				local rule = s.rule and tostring(s.rule)
-
-				if rule and rule:match("^%S+$") then
-					line[#line+1] = rule
-
-					local name = s.name and tostring(s.name)
-					if name and name:match("^%S+$") then
-						line[#line+1] = name
-					end
-				end
-
-				str = str .. table.concat(line, " ") .. "\n"
-			end
-		end
-	end
-
-	return str
-end
-
-function config_network( c )
-	local str = ""
-
-	for s in pairs(sections) do
-		for key, type in pairs({ Listen="collectd_network_listen", Server="collectd_network_server" }) do
-			if sections[s][".type"] == type then
-
-				host = sections[s].host
-				port = sections[s].port
-
-				if host then
-					if port then
-						str = str .. "\t" .. key .. " \"" .. host .. "\" \"" .. port .. "\"\n"
-					else
-						str = str .. "\t" .. key .. " \"" .. host .. "\"\n"
-					end
-				end
-						end
-				end
-		end
-
-	return str ..
-		_string(c["MaxPacketSize"], "MaxPacketSize") ..
-		_string(c["TimeToLive"], "TimeToLive") ..
-		_bool(c["Forward"], "Forward") ..
-		_bool(c["ReportStats"], "ReportStats")
-end
-
-
-function _list_expand( c, l, nopad )
-	local str = ""
-
-	for i, n in ipairs(l) do
-		if c[n] then
-			if preprocess[n] then
-				c[n] = preprocess[n](c[n])
-			end
-
-			if n:find("(%w+)ses") then
-				k = n:gsub("(%w+)ses$", "%1s")
-			else
-				k = n:gsub("(%w+)s$", "%1")
-			end
-
-			str = str .. _expand( c[n], k, nopad )
-		end
-	end
-
-	return str
-end
-
-function _expand( s, n, nopad )
-	local str = ""
-
-	if type(s) == "string" then
-		for i, v in ipairs( luci.util.split( s, "%s+", nil, true ) ) do
-			str = str .. _string( v, n, nopad )
-		end
-	elseif type(s) == "table" then
-		for i, v in ipairs(s) do
-			str = str .. _string( v, n, nopad )
-		end
-	end
-
-	return str
-end
-
-function _bool( s, n, nopad )
-
-	local str = ""
-	local pad = ""
-	if not nopad then pad = "\t" end
-
-	if s == "1" then
-		str = pad .. n .. " true\n"
-	elseif s == "0" then
-		str = pad .. n .. " false\n"
-	end
-
-	return str
-end
-
-function _string( s, n, nopad )
-
-	local str = ""
-	local pad = ""
-	if not nopad then pad = "\t" end
-
-	if s then
-		if s:find("[^%d]") or n == "Port" or n == "Irq" then
-			if not s:find("[^%w]") and n ~= "Port" and n ~= "Irq" then
-				str = pad .. n .. " " .. luci.util.trim(s)
-			else
-				str = pad .. n .. ' "' .. luci.util.trim(s) .. '"'
-			end
-		else
-			str = pad .. n .. " " .. luci.util.trim(s)
-		end
-
-		str = str .. "\n"
-	end
-
-	return str
-end
-
-
-plugins = {
-	collectd = {
-		{ "BaseDir", "Include", "PIDFile", "PluginDir", "TypesDB", "Interval", "ReadThreads", "Hostname" },
-		{ },
-		{ }
-	},
-	logfile	= {
-		{ "LogLevel", "File" },
-		{ "Timestamp" },
-		{ }
-	},
-}
-
-local plugin_dir = "/usr/share/luci/statistics/plugins/"
-for filename in nixio.fs.dir(plugin_dir) do
-	local name = filename:gsub("%.json", "")
-	if (name == "exec") then
-		plugins[name] = config_exec
-	elseif (name == "iptables") then
-		plugins[name] = config_iptables
-	elseif (name == "curl") then
-		plugins[name] = config_curl
-	elseif (name == "network") then
-		plugins[name] = config_network
-	else
-		local plugin_def = luci.jsonc.parse(nixio.fs.readfile(plugin_dir .. filename))
-		if type(plugin_def) == "table" then
-			plugins[name] = plugin_def.legend
-		end
-	end
-end
-
-
-preprocess = {
-	RRATimespans = function(val)
-		local rv = { }
-		for time in luci.util.imatch(val) do
-			table.insert( rv, luci.util.parse_units(time) )
-		end
-		return table.concat(rv, " ")
-	end
-}
-
-
-section("collectd")
-
-section("logfile")
-
-for plugin in pairs(plugins) do
-	if (plugin ~= "collectd") and (plugin ~= "logfile") then
-		section( plugin )
-	end
-end
diff --git a/applications/luci-app-statistics/root/usr/libexec/stat-genconfig b/applications/luci-app-statistics/root/usr/libexec/stat-genconfig
new file mode 100755
index 0000000000..d60e1a69ed
--- /dev/null
+++ b/applications/luci-app-statistics/root/usr/libexec/stat-genconfig
@@ -0,0 +1,284 @@
+#!/usr/bin/env ucode
+/*
+Luci statistics - collectd configuration generator
+(c) 2008-2022 Jo-Philipp Wich <jo@mein.io>
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+		http://www.apache.org/licenses/LICENSE-2.0
+
+*/
+
+'use strict';
+
+import { lsdir, open } from 'fs';
+import { cursor } from 'uci';
+
+const uci = cursor();
+const sections = uci.get_all('luci_statistics');
+
+const plugins = {
+	collectd: [
+		[ 'BaseDir', 'Include', 'PIDFile', 'PluginDir', 'TypesDB', 'Interval', 'ReadThreads', 'Hostname' ],
+		[],
+		[]
+	],
+	logfile: [
+		[ 'LogLevel', 'File' ],
+		[ 'Timestamp' ],
+		[]
+	],
+};
+
+function parse_units(ustr) {
+	let val = 0;
+
+	// unit map
+	const map = {
+		y  : 60 * 60 * 24 * 366,
+		m  : 60 * 60 * 24 * 31,
+		w  : 60 * 60 * 24 * 7,
+		d  : 60 * 60 * 24,
+		h  : 60 * 60,
+		min: 60
+	};
+
+	// parse input string
+	for (let spec in match(lc(ustr), /([0-9.]+)([a-z]*)/g)) {
+		let num = +spec[1];
+		let mul = map[spec[2]] ?? map[substr(spec[2], 0, 1)] ?? 1;
+
+		val += num * mul;
+	}
+
+	return int(val);
+}
+
+const preprocess = {
+	RRATimespans: function(val) {
+		return join(' ', map(split(val, /\s+/), parse_units));
+	}
+};
+
+
+function _bool(s, n, nopad) {
+	if (s == '1')
+		return `${nopad ? '' : '\t'}${n} true\n`;
+
+	if (s == '0')
+		return `${nopad ? '' : '\t'}${n} false\n`;
+
+	return '';
+}
+
+function _string(s, n, nopad) {
+	if (s) {
+		if (n == 'Port' || n == 'Irq' || match(s, /[^0-9]/)) {
+			if (!match(s, /[^\w]/) && n != 'Port' && n != 'Irq')
+				return `${nopad ? '' : '\t'}${n} ${trim(s)}\n`;
+			else
+				return `${nopad ? '' : '\t'}${n} "${trim(s)}"\n`;
+		}
+		else {
+			return `${nopad ? '' : '\t'}${n} ${trim(s)}\n`;
+		}
+	}
+
+	return '';
+}
+
+function _expand(s, n, nopad) {
+	let str = "";
+
+	if (type(s) == 'string') {
+		for (let v in split(s, /\s+/))
+			str += _string(v, n, nopad);
+	}
+	else if (type(s) == 'array') {
+		for (let v in s)
+			str += _string(v, n, nopad);
+	}
+
+	return str;
+}
+
+function _list_expand(c, l, nopad) {
+	let str = '';
+
+	for (let n in l) {
+		if (c[n]) {
+			if (preprocess[n])
+				c[n] = preprocess[n](c[n]);
+
+			let m = match(n, /^(\w+)ses$/);
+			let k;
+
+			if (m)
+				k = `${m[1]}s`;
+			else
+				k = replace(n, /^(\w+)s$/, '$1');
+
+			str += _expand(c[n], k, nopad);
+		}
+	}
+
+	return str;
+}
+
+
+function config_generic(c, singles, bools, lists, nopad) {
+	let str = '';
+
+	if (c) {
+		for (let key in singles) {
+			if (preprocess[key])
+				c[key] = preprocess[key](c[key]);
+
+			str += _string(c[key], key, nopad);
+		}
+
+		for (let key in bools) {
+			if (preprocess[key])
+				c[key] = preprocess[key](c[key]);
+
+			str += _bool(c[key], key, nopad);
+		}
+
+		if (lists)
+			str += _list_expand(c, lists, nopad);
+	}
+
+	return str;
+}
+
+function config_exec(c) {
+	let str = "";
+
+	for (let k, s in sections) {
+		for (let key, type in { Exec: 'collectd_exec_input', NotificationExec: 'collectd_exec_notify' }) {
+			if (s['.type'] == type) {
+				let cmd   = replace(trim(s.cmdline), /\s+/g, '" "');
+				let user  = s.cmduser ?? 'nobody';
+				let group = s.cmdgroup;
+
+				if (cmd)
+					str += `\t${key} "${user}${group ? `:${group}` : ''}" "${cmd}"\n`;
+			}
+		}
+	}
+
+	return str;
+}
+
+function config_curl(c) {
+	let str = "";
+
+	for (let k, s in sections) {
+		if (s['.type'] == 'collectd_curl_page') {
+			str += `\t<Page "${s.name}">\n`
+			     + `\t\tURL "${s.url}"\n`
+			     + `\t\tMeasureResponseTime true\n`
+			     + `\t</Page>\n`;
+		}
+	}
+
+	return str;
+}
+
+function config_iptables(c) {
+	let str = "";
+
+	for (let k, s in sections) {
+		for (let type, verb in { collectd_iptables_match: 'Chain', collectd_iptables_match6: 'Chain6' }) {
+			if (s['.type'] == type) {
+				let tname = `${s.table}`;
+				let chain = `${s.chain}`;
+
+				if (match(tname, /^\S+$/) && match(chain, /^\S+$/) && match(rule, /^\S+$/) && match(name, /^\S+$/)) {
+					str += `\t${verb} "${tname}" "${chain}"`;
+
+					let rule = `${s.rule}`;
+
+					if (match(rule, /^\S+$/)) {
+						str += ` "${rule}"`;
+
+						let name = `${s.name}`;
+
+						if (match(name, /^\S+$/))
+							str += ` "${name}"`;
+					}
+
+					str += '\n';
+				}
+			}
+		}
+	}
+
+	return str;
+}
+
+function config_network(c) {
+	let str = '';
+
+	for (let k, s in sections) {
+		for (let key, type in { Listen: 'collectd_network_listen', Server: 'collectd_network_server' }) {
+			if (s['.type'] == type && s.host) {
+				if (s.port)
+					str += `\t${key} "${s.host}" "${s.port}"\n`;
+				else
+					str += `\t${key} "${s.host}"\n`;
+			}
+		}
+	}
+
+	return str
+		+ _string(c.MaxPacketSize, 'MaxPacketSize')
+		+ _string(c.TimeToLive, 'TimeToLive')
+		+ _bool(c.Forward, 'Forward')
+		+ _bool(c.ReportStats, 'ReportStats')
+	;
+}
+
+function section(plugin) {
+	let config = sections[`collectd_${plugin}`] ?? sections.collectd;
+
+	if (config && (plugin == 'collectd' || config.enable == '1')) {
+		let params;
+
+		if (type(plugins[plugin]) == 'function')
+			params = plugins[plugin](config);
+		else
+			params = config_generic(config, ...plugins[plugin], plugin == 'collectd');
+
+		if (plugin != 'collectd')
+			print(`LoadPlugin ${plugin}\n${length(params) ? `<Plugin ${plugin}>\n${params}</Plugin>\n` : ''}\n`);
+		else
+			print(`${params ?? ''}\n`);
+	}
+}
+
+
+let plugin_dir = '/usr/share/luci/statistics/plugins';
+
+for (let filename in lsdir(plugin_dir)) {
+	let name = replace(filename, /\.json$/, '');
+
+	switch (name) {
+	case 'exec':     plugins[name] = config_exec;     break;
+	case 'iptables': plugins[name] = config_iptables; break;
+	case 'curl':     plugins[name] = config_curl;     break;
+	case 'network':  plugins[name] = config_network;  break;
+	default:
+		plugins[name] = json(open(`${plugin_dir}/${filename}`))?.legend;
+	}
+}
+
+
+section('collectd');
+section('logfile');
+
+for (let plugin in plugins)
+	if (plugin != 'collectd' && plugin != 'logfile')
+		section(plugin);