int luaLogCommand(lua_State *lua) {
int j, argc = lua_gettop(lua);
int level;
sds log;
if (argc < 2) {
luaPushError(lua, "redis.log() requires two arguments or more.");
return 1;
} else if (!lua_isnumber(lua,-argc)) {
luaPushError(lua, "First argument must be a number (log level).");
return 1;
}
level = lua_tonumber(lua,-argc);
if (level < REDIS_DEBUG || level > REDIS_WARNING) {
luaPushError(lua, "Invalid debug level.");
return 1;
}
/* Glue together all the arguments */
log = sdsempty();
for (j = 1; j < argc; j++) {
size_t len;
char *s;
s = (char*)lua_tolstring(lua,(-argc)+j,&len);
if (s) {
if (j != 1) log = sdscatlen(log," ",1);
log = sdscatlen(log,s,len);
}
}
redisLogRaw(level,log);
sdsfree(log);
return 0;
}
// redis log(组织日志内容)
void redisLog(int level, const char *fmt, ...) {
va_list ap;
char msg[REDIS_MAX_LOGMSG_LEN];
// & 0xff(补码), level永为正
if ((level & 0xff) < server.verbosity) return;
va_start(ap, fmt);
vsnprintf(msg, sizeof(msg), fmt, ap);
va_end(ap);
// 根据设定的日志等级来写日志
redisLogRaw(level, msg);
}
/* Like redisLogRaw() but with printf-alike support. This is the function that
* is used across the code. The raw version is only used in order to dump
* the INFO output on crash. */
void redisLog(int level, const char *fmt, ...) {
va_list ap;
char msg[REDIS_MAX_LOGMSG_LEN];
int vlen;
if ((level&0xff) < verbosity) return;
va_start(ap, fmt);
vlen = vsnprintf(msg, sizeof(msg), fmt, ap);
va_end(ap);
/* The MS CRT implementation of vsnprintf/snprintf returns -1 if the formatted output doesn't fit the buffer,
* in addition to when an encoding error occurs. Proceeding with a zero-terminated ellipsis at the end of the
* buffer seems a better option than not logging this message at all.
*/
if (vlen < 0 || vlen >= sizeof(msg)) {
strncpy(msg + sizeof(msg) - sizeof(ellipsis), ellipsis, sizeof(ellipsis));
}
redisLogRaw(level,msg);
}
