view mod_storage_appendmap/mod_storage_appendmap.lua @ 5648:c217f4edfc4f

misc/mtail: Start of an mtail config Stashing it here in case anyone wants to continue working on it. Currently it's only counting log messages by level. Due to the permissions set by systemd on Prosody logs, mtail never managed to start correctly until permissions were manually relaxed.
author Kim Alvefur <zash@zash.se>
date Sun, 17 Sep 2023 13:36:30 +0200
parents e44b868cc575
children ea6c18ec0669
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local dump = require "util.serialization".serialize;
local load = require "util.envload".envloadfile;
local dm = require "core.storagemanager".olddm;

local REMOVE = {}; -- Special value for removing keys

local driver = {};


local keywords = {
	["do"] = true; ["and"] = true; ["else"] = true; ["break"] = true;
	["if"] = true; ["end"] = true; ["goto"] = true; ["false"] = true;
	["in"] = true; ["for"] = true; ["then"] = true; ["local"] = true;
	["or"] = true; ["nil"] = true; ["true"] = true; ["until"] = true;
	["elseif"] = true; ["function"] = true; ["not"] = true;
	["repeat"] = true; ["return"] = true; ["while"] = true;

	-- _ENV is not technically a keyword but we need to treat it as such
	["_ENV"] = true;
};

local function is_usable_identifier(s)
	return type(s) == "string" and not keywords[s] and s:find("^[%a_][%w_]*$");
end

local function serialize_key(key)
	if is_usable_identifier(key) then
		return key;
	else
		return "_ENV[" .. dump(key) .. "]";
	end
end

local function serialize_value(value)
	if value == REMOVE then
		return "nil";
	else
		return dump(value);
	end
end

local function serialize_pair(key, value)
	key = serialize_key(key);
	value = serialize_value(value);
	return key .. " = " .. value .. ";\n";
end

local function serialize_map(keyvalues)
	local keys, values = {}, {};
	for key, value in pairs(keyvalues) do
		key = serialize_key(key);
		value = serialize_value(value);
		table.insert(keys, key);
		table.insert(values, value);
	end
	return table.concat(keys, ", ") .. " = " .. table.concat(values, ", ") .. ";\n";
end

local map = { remove = REMOVE };
local map_mt = { __index = map };

function map:get(user, key)
	module:log("debug", "map:get(%s, %s)", tostring(user), tostring(key))
	local filename = dm.getpath(user, module.host, self.store, "map");
	module:log("debug", "File is %s", filename);
	local env = {};
	if _VERSION == "Lua 5.1" then -- HACK
		env._ENV = env; -- HACK
	end -- SO MANY HACKS
	local chunk, err, errno = load(filename, env);
	if not chunk then if errno == 2 then return end return chunk, err; end
	local ok, err = pcall(chunk);
	if not ok then return ok, err; end
	if _VERSION == "Lua 5.1" then -- HACK
		env._ENV = nil; -- HACK
	end -- HACKS EVERYWHERE
	if key == nil then
		return env;
	end
	return env[key];
end

function map:set_keys(user, keyvalues)
	local data = serialize_map(keyvalues);
	return dm.append_raw(user, module.host, self.store, "map", data);
end

function map:set(user, key, value)
	if _VERSION == "Lua 5.1" then
		assert(key ~= "_ENV", "'_ENV' is a restricted key");
	end
	if key == nil then
		local filename = dm.getpath(user, module.host, self.store, "map");
		return os.remove(filename);
	end
	local data = serialize_pair(key, value);
	return dm.append_raw(user, module.host, self.store, "map", data);
end

local keyval = { remove = REMOVE };
local keyval_mt = { __index = keyval };

function keyval:get(user)
	return map.get(self, user, nil);
end

function keyval:set(user, keyvalues)
	local data = serialize_map(keyvalues);
	return dm.store_raw(dm.getpath(user, module.host, self.store, "map"), data);
end

-- TODO some kind of periodic compaction thing?
function map:_compact(user)
	local data = self:get(user);
	return keyval.set(self, user, data);
end

function driver:open(store, typ)
	if typ == "map" then
		return setmetatable({ store = store, }, map_mt);
	elseif typ == nil or typ == "keyval" then
		return setmetatable({ store = store, }, keyval_mt);
	end
	return nil, "unsupported-store";
end

module:provides("storage", driver);