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#pragma once
#include "common/dout.h"
#include "rgw_common.h"
#include <string>
#include <unordered_map>
#include <variant>
#include "rgw_lua_utils.h"
#include "rgw_realm_reloader.h"
namespace rgw::lua {
//Interval between each execution of the script is set to 5 seconds
constexpr const int INIT_EXECUTE_INTERVAL = 5;
//Writeable meta table named RGW with mutex protection
using BackgroundMapValue = std::variant<std::string, long long int, double, bool>;
using BackgroundMap = std::unordered_map<std::string, BackgroundMapValue>;
inline void pushvalue(lua_State* L, const std::string& value) {
pushstring(L, value);
}
inline void pushvalue(lua_State* L, long long value) {
lua_pushinteger(L, value);
}
inline void pushvalue(lua_State* L, double value) {
lua_pushnumber(L, value);
}
inline void pushvalue(lua_State* L, bool value) {
lua_pushboolean(L, value);
}
struct RGWTable : EmptyMetaTable {
static const char* INCREMENT;
static const char* DECREMENT;
static std::string TableName() {return "RGW";}
static std::string Name() {return TableName() + "Meta";}
static int increment_by(lua_State* L);
static int IndexClosure(lua_State* L) {
const auto map = reinterpret_cast<BackgroundMap*>(lua_touserdata(L, lua_upvalueindex(FIRST_UPVAL)));
auto& mtx = *reinterpret_cast<std::mutex*>(lua_touserdata(L, lua_upvalueindex(SECOND_UPVAL)));
const char* index = luaL_checkstring(L, 2);
if (strcasecmp(index, INCREMENT) == 0) {
lua_pushlightuserdata(L, map);
lua_pushlightuserdata(L, &mtx);
lua_pushboolean(L, false /*increment*/);
lua_pushcclosure(L, increment_by, THREE_UPVALS);
return ONE_RETURNVAL;
}
if (strcasecmp(index, DECREMENT) == 0) {
lua_pushlightuserdata(L, map);
lua_pushlightuserdata(L, &mtx);
lua_pushboolean(L, true /*decrement*/);
lua_pushcclosure(L, increment_by, THREE_UPVALS);
return ONE_RETURNVAL;
}
std::lock_guard l(mtx);
const auto it = map->find(std::string(index));
if (it == map->end()) {
lua_pushnil(L);
} else {
std::visit([L](auto&& value) { pushvalue(L, value); }, it->second);
}
return ONE_RETURNVAL;
}
static int LenClosure(lua_State* L) {
const auto map = reinterpret_cast<BackgroundMap*>(lua_touserdata(L, lua_upvalueindex(FIRST_UPVAL)));
auto& mtx = *reinterpret_cast<std::mutex*>(lua_touserdata(L, lua_upvalueindex(SECOND_UPVAL)));
std::lock_guard l(mtx);
lua_pushinteger(L, map->size());
return ONE_RETURNVAL;
}
static int NewIndexClosure(lua_State* L) {
const auto map = reinterpret_cast<BackgroundMap*>(lua_touserdata(L, lua_upvalueindex(FIRST_UPVAL)));
auto& mtx = *reinterpret_cast<std::mutex*>(lua_touserdata(L, lua_upvalueindex(SECOND_UPVAL)));
const auto index = luaL_checkstring(L, 2);
if (strcasecmp(index, INCREMENT) == 0 || strcasecmp(index, DECREMENT) == 0) {
return luaL_error(L, "increment/decrement are reserved function names for RGW");
}
std::unique_lock l(mtx);
size_t len;
BackgroundMapValue value;
const int value_type = lua_type(L, 3);
switch (value_type) {
case LUA_TNIL:
map->erase(std::string(index));
return NO_RETURNVAL;
case LUA_TBOOLEAN:
value = static_cast<bool>(lua_toboolean(L, 3));
len = sizeof(bool);
break;
case LUA_TNUMBER:
if (lua_isinteger(L, 3)) {
value = lua_tointeger(L, 3);
len = sizeof(long long int);
} else {
value = lua_tonumber(L, 3);
len = sizeof(double);
}
break;
case LUA_TSTRING:
{
const auto str = lua_tolstring(L, 3, &len);
value = std::string{str, len};
break;
}
default:
l.unlock();
return luaL_error(L, "unsupported value type for RGW table");
}
if (len + strnlen(index, MAX_LUA_VALUE_SIZE)
> MAX_LUA_VALUE_SIZE) {
return luaL_error(L, "Lua maximum size of entry limit exceeded");
} else if (map->size() > MAX_LUA_KEY_ENTRIES) {
l.unlock();
return luaL_error(L, "Lua max number of entries limit exceeded");
} else {
map->insert_or_assign(index, value);
}
return NO_RETURNVAL;
}
static int PairsClosure(lua_State* L) {
auto map = reinterpret_cast<BackgroundMap*>(lua_touserdata(L, lua_upvalueindex(FIRST_UPVAL)));
ceph_assert(map);
lua_pushlightuserdata(L, map);
lua_pushcclosure(L, stateless_iter, ONE_UPVAL); // push the stateless iterator function
lua_pushnil(L); // indicate this is the first call
// return stateless_iter, nil
return TWO_RETURNVALS;
}
static int stateless_iter(lua_State* L) {
// based on: http://lua-users.org/wiki/GeneralizedPairsAndIpairs
auto map = reinterpret_cast<BackgroundMap*>(lua_touserdata(L, lua_upvalueindex(FIRST_UPVAL)));
typename BackgroundMap::const_iterator next_it;
if (lua_isnil(L, -1)) {
next_it = map->begin();
} else {
const char* index = luaL_checkstring(L, 2);
const auto it = map->find(std::string(index));
ceph_assert(it != map->end());
next_it = std::next(it);
}
if (next_it == map->end()) {
// index of the last element was provided
lua_pushnil(L);
lua_pushnil(L);
// return nil, nil
} else {
pushstring(L, next_it->first);
std::visit([L](auto&& value) { pushvalue(L, value); }, next_it->second);
// return key, value
}
return TWO_RETURNVALS;
}
};
class Background : public RGWRealmReloader::Pauser {
private:
BackgroundMap rgw_map;
bool stopped = false;
bool started = false;
bool paused = false;
int execute_interval;
const DoutPrefix dp;
std::unique_ptr<rgw::sal::LuaManager> lua_manager;
CephContext* const cct;
const std::string luarocks_path;
std::thread runner;
mutable std::mutex table_mutex;
std::mutex cond_mutex;
std::mutex pause_mutex;
std::condition_variable cond;
static const BackgroundMapValue empty_table_value;
void run();
protected:
std::string rgw_script;
virtual int read_script();
public:
Background(rgw::sal::Driver* driver,
CephContext* cct,
const std::string& luarocks_path,
int execute_interval = INIT_EXECUTE_INTERVAL);
virtual ~Background() = default;
void start();
void shutdown();
void create_background_metatable(lua_State* L);
const BackgroundMapValue& get_table_value(const std::string& key) const;
template<typename T>
void put_table_value(const std::string& key, T value) {
std::unique_lock cond_lock(table_mutex);
rgw_map[key] = value;
}
void pause() override;
void resume(rgw::sal::Driver* _driver) override;
};
} //namepsace rgw::lua
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