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Refactor eval commands #1313

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merged 1 commit into from
Mar 11, 2023
Merged

Refactor eval commands #1313

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48 changes: 20 additions & 28 deletions src/commands/cmd_script.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -26,44 +26,36 @@

namespace Redis {

class CommandEval : public Commander {
public:
Status Parse(const std::vector<std::string> &args) override { return Status::OK(); }

Status Execute(Server *svr, Connection *conn, std::string *output) override {
return Lua::evalGenericCommand(conn, args_, false, output);
}
};

class CommandEvalSHA : public Commander {
template <bool evalsha, bool read_only>
class CommandEvalImpl : public Commander {
public:
Status Execute(Server *svr, Connection *conn, std::string *output) override {
if (args_[1].size() != 40) {
if (evalsha && args_[1].size() != 40) {
*output = Redis::Error(errNoMatchingScript);
return Status::OK();
}
return Lua::evalGenericCommand(conn, args_, true, output);
}
};

class CommandEvalRO : public Commander {
public:
Status Execute(Server *svr, Connection *conn, std::string *output) override {
return Lua::evalGenericCommand(conn, args_, false, output, true);
}
};

class CommandEvalSHARO : public Commander {
public:
Status Execute(Server *svr, Connection *conn, std::string *output) override {
if (args_[1].size() != 40) {
*output = Redis::Error(errNoMatchingScript);
return Status::OK();
int64_t numkeys = GET_OR_RET(ParseInt<int64_t>(args_[2], 10));
if (numkeys > int64_t(args_.size() - 3)) {
return {Status::NotOK, "Number of keys can't be greater than number of args"};
} else if (numkeys < -1) {
return {Status::NotOK, "Number of keys can't be negative"};
}
return Lua::evalGenericCommand(conn, args_, true, output, true);

return Lua::evalGenericCommand(
conn, args_[1], std::vector<std::string>(args_.begin() + 3, args_.begin() + 3 + numkeys),
std::vector<std::string>(args_.begin() + 3 + numkeys, args_.end()), evalsha, output, read_only);
}
};

class CommandEval : public CommandEvalImpl<false, false> {};

class CommandEvalSHA : public CommandEvalImpl<true, false> {};

class CommandEvalRO : public CommandEvalImpl<false, true> {};

class CommandEvalSHARO : public CommandEvalImpl<true, true> {};

class CommandScript : public Commander {
public:
Status Parse(const std::vector<std::string> &args) override {
Expand Down
101 changes: 50 additions & 51 deletions src/storage/scripting.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -134,33 +134,30 @@ void loadFuncs(lua_State *lua, bool read_only) {
* Note that when the error is in the C function we want to report the
* information about the caller, that's what makes sense from the point
* of view of the user debugging a script. */
{
const char *err_func =
"local dbg = debug\n"
"function __redis__err__handler(err)\n"
" local i = dbg.getinfo(2,'nSl')\n"
" if i and i.what == 'C' then\n"
" i = dbg.getinfo(3,'nSl')\n"
" end\n"
" if i then\n"
" return i.source .. ':' .. i.currentline .. ': ' .. err\n"
" else\n"
" return err\n"
" end\n"
"end\n";
luaL_loadbuffer(lua, err_func, strlen(err_func), "@err_handler_def");
lua_pcall(lua, 0, 0, 0);
}
{
const char *compare_func =
"function __redis__compare_helper(a,b)\n"
" if a == false then a = '' end\n"
" if b == false then b = '' end\n"
" return a<b\n"
"end\n";
luaL_loadbuffer(lua, compare_func, strlen(compare_func), "@cmp_func_def");
lua_pcall(lua, 0, 0, 0);
}
const char *err_func =
"local dbg = debug\n"
"function __redis__err__handler(err)\n"
" local i = dbg.getinfo(2,'nSl')\n"
" if i and i.what == 'C' then\n"
" i = dbg.getinfo(3,'nSl')\n"
" end\n"
" if i then\n"
" return i.source .. ':' .. i.currentline .. ': ' .. err\n"
" else\n"
" return err\n"
" end\n"
"end\n";
luaL_loadbuffer(lua, err_func, strlen(err_func), "@err_handler_def");
lua_pcall(lua, 0, 0, 0);

const char *compare_func =
"function __redis__compare_helper(a,b)\n"
" if a == false then a = '' end\n"
" if b == false then b = '' end\n"
" return a<b\n"
"end\n";
luaL_loadbuffer(lua, compare_func, strlen(compare_func), "@cmp_func_def");
lua_pcall(lua, 0, 0, 0);
}

int redisLogCommand(lua_State *lua) {
Expand Down Expand Up @@ -204,29 +201,22 @@ int redisLogCommand(lua_State *lua) {
return 0;
}

Status evalGenericCommand(Redis::Connection *conn, const std::vector<std::string> &args, bool evalsha,
std::string *output, bool read_only) {
Status evalGenericCommand(Redis::Connection *conn, const std::string &body_or_sha, const std::vector<std::string> &keys,
const std::vector<std::string> &argv, bool evalsha, std::string *output, bool read_only) {
Server *srv = conn->GetServer();

// Use the worker's private Lua VM when entering the read-only mode
lua_State *lua = read_only ? conn->Owner()->Lua() : srv->Lua();

int64_t numkeys = GET_OR_RET(ParseInt<int64_t>(args[2], 10));
if (numkeys > int64_t(args.size() - 3)) {
return {Status::NotOK, "Number of keys can't be greater than number of args"};
} else if (numkeys < -1) {
return {Status::NotOK, "Number of keys can't be negative"};
}

/* We obtain the script SHA1, then check if this function is already
* defined into the Lua state */
char funcname[2 + 40 + 1] = REDIS_LUA_FUNC_SHA_PREFIX;

if (!evalsha) {
SHA1Hex(funcname + 2, args[1].c_str(), args[1].size());
SHA1Hex(funcname + 2, body_or_sha.c_str(), body_or_sha.size());
} else {
for (int j = 0; j < 40; j++) {
funcname[j + 2] = static_cast<char>(tolower(args[1][j]));
funcname[j + 2] = static_cast<char>(tolower(body_or_sha[j]));
}
}

Expand All @@ -245,10 +235,10 @@ Status evalGenericCommand(Redis::Connection *conn, const std::vector<std::string
return {Status::NotOK, "NOSCRIPT No matching script. Please use EVAL"};
}
} else {
body = args[1];
body = body_or_sha;
}

std::string sha;
std::string sha = funcname + 2;
auto s = createFunction(srv, body, &sha, lua, false);
if (!s.IsOK()) {
lua_pop(lua, 1); /* remove the error handler from the stack. */
Expand All @@ -260,8 +250,8 @@ Status evalGenericCommand(Redis::Connection *conn, const std::vector<std::string

/* Populate the argv and keys table accordingly to the arguments that
* EVAL received. */
setGlobalArray(lua, "KEYS", std::vector<std::string>(args.begin() + 3, args.begin() + 3 + numkeys));
setGlobalArray(lua, "ARGV", std::vector<std::string>(args.begin() + 3 + numkeys, args.end()));
setGlobalArray(lua, "KEYS", keys);
setGlobalArray(lua, "ARGV", argv);

if (lua_pcall(lua, 0, 1, -2)) {
auto msg = fmt::format("ERR running script (call to {}): {}", funcname, lua_tostring(lua, -1));
Expand All @@ -272,22 +262,27 @@ Status evalGenericCommand(Redis::Connection *conn, const std::vector<std::string
lua_pop(lua, 1);
}

// clean global variables to prevent information leak in function commands
lua_pushnil(lua);
lua_setglobal(lua, "KEYS");
lua_pushnil(lua);
lua_setglobal(lua, "ARGV");

/* Call the Lua garbage collector from time to time to avoid a
* full cycle performed by Lua, which adds too latency.
*
* The call is performed every LUA_GC_CYCLE_PERIOD executed commands
* (and for LUA_GC_CYCLE_PERIOD collection steps) because calling it
* for every command uses too much CPU. */
constexpr int64_t LUA_GC_CYCLE_PERIOD = 50;
{
static int64_t gc_count = 0;
static int64_t gc_count = 0;

gc_count++;
if (gc_count == LUA_GC_CYCLE_PERIOD) {
lua_gc(lua, LUA_GCSTEP, LUA_GC_CYCLE_PERIOD);
gc_count = 0;
}
gc_count++;
if (gc_count == LUA_GC_CYCLE_PERIOD) {
lua_gc(lua, LUA_GCSTEP, LUA_GC_CYCLE_PERIOD);
gc_count = 0;
}

return Status::OK();
}

Expand Down Expand Up @@ -875,8 +870,12 @@ int redisMathRandomSeed(lua_State *L) {
Status createFunction(Server *srv, const std::string &body, std::string *sha, lua_State *lua, bool need_to_store) {
char funcname[2 + 40 + 1] = REDIS_LUA_FUNC_SHA_PREFIX;

SHA1Hex(funcname + 2, body.c_str(), body.size());
*sha = funcname + 2;
if (sha->empty()) {
SHA1Hex(funcname + 2, body.c_str(), body.size());
*sha = funcname + 2;
} else {
std::copy(sha->begin(), sha->end(), funcname + 2);
}

auto funcdef = fmt::format("function {}() {}\nend", funcname, body);

Expand Down
5 changes: 3 additions & 2 deletions src/storage/scripting.h
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Original file line number Diff line number Diff line change
Expand Up @@ -49,8 +49,9 @@ int redisLogCommand(lua_State *lua);

Status createFunction(Server *srv, const std::string &body, std::string *sha, lua_State *lua, bool need_to_store);

Status evalGenericCommand(Redis::Connection *conn, const std::vector<std::string> &args, bool evalsha,
std::string *output, bool read_only = false);
Status evalGenericCommand(Redis::Connection *conn, const std::string &body_or_sha, const std::vector<std::string> &keys,
const std::vector<std::string> &argv, bool evalsha, std::string *output,
bool read_only = false);

const char *redisProtocolToLuaType(lua_State *lua, const char *reply);
const char *redisProtocolToLuaType_Int(lua_State *lua, const char *reply);
Expand Down