This change does not log the file name and line numbers,
but the function name. Together with the commit information
that is logged in conjunction with a crash and that MaxScale
can tell, when invoked, that is enough to be able to pinpoint
the location where a logging was made. Furthermore, that is
a lot less intrusive and less confusing for an
end-user than filename + line.
This is just a temporary workaround; the logging mechanism
needs to get an overhaul:
- Separate severity and logging target.
- Take syslog severities into use.
- Simplify what needs to be done by developer.
- etc.
void session_enable_log(SESSION* ses, logfile_id_t id)
and
void session_disable_log(SESSION* ses, logfile_id_t id)
Which switch specific log type on/off if the log type in question is not generally enabled.
Each thread carries a thread-specific struct log_info_t which includes members for current session id and bitfield for enabled log types for the current session. That information is checked before actual log write functions are called.
Each file where session-specific logging is used, must include the following exports:
/** Defined in log_manager.cc */
extern int lm_enabled_logfiles_bitmask;
extern size_t log_ses_count[];
extern __thread log_info_t tls_log_info;
Added macros which allow for testing locally if log is enabled or not.
server/Makefile
Added directory creation command to Makefile. This fixes problem where errmsg.sys was copied to MaxScale/mysql instead of MaxScale/mysql/errmsg.sys
dcb.b
Added external variable which carries the information of enabled logs from log_manager.cc
gateway.c
Tuned logging.
Added new argument '-s' which takes additional argument composed of list of logfile identifiers. Logfiles listed with '-s' will be written on main memory instead of disk. In practice, the log file in question will be written in /dev/shm but corresponding symlink is added to log directory. In the case of name conflicts with log files and links, a differentiating sequence number is included in hte name of the file. This, however, is done only when existing file is not writable or is of different type (symlink <> file).
Added new logfile LOGFILE_DEBUG whose contents will be largerly what was included up to date in trace log.
Disabled feature which spreads writes to log files to others because of bug (#338) in the way block buffers are managed.
Changed log manager parameters to match with the current implementation. List of arguments:
"-h - help\n"
"-a <debug prefix> ............(\"skygw_debug\")\n"
"-b <debug suffix> ............(\".log\")\n"
"-c <trace prefix> ............(\"skygw_trace\")\n"
"-d <trace suffix> ............(\".log\")\n"
"-e <message prefix> ............(\"skygw_msg\")\n"
"-f <message suffix> ............(\".log\")\n"
"-g <error prefix> ............(\"skygw_err\")\n"
"-i <error suffix> ............(\".log\")\n"
"-j <log path> ............(\"/tmp\")\n"
"-s <shmem log file ids> ........(no default)\n";
dcb.c
dcb_add_to_zombieslist, add dcb to the front of zombies list instead of inserting to the end of it.
gateway.c
Renamed shutdown_gateway to shutdown_server (Bug #131)
Call skygw_logmanager_init so that trace and debug logs are written to shared memory.
poll.c
dcb.h
Removed some dead code and references to unneeded mutexes.
debugcmd.c
Added enable/disable log command for debug log.
skygw_utils.cc
skygw_file_init now takes optional symlink name as a second argument. Symlink is created to point to the file being created.
LOGFILE_ERROR = 1
LOGFILE_MESSAGE = 2
LOGFILE_TRACE = 4
What is written to file n, will be written to all files m, m>n. Applies to user log writes. Some internal messages are such that they apply to one specific file, such as enable/disable notifications.
/** No change in these */
bool skygw_logmanager_init(void** buf, int argc, char* argv[]);
void skygw_logmanager_done(void** buf);
void skygw_logmanager_exit(void);
int skygw_log_flush(logfile_id_t id);
/** writebuf remains unused, but formatted string is now possible and in case
* of formatted string, arbitrary long argument list is supported too. Max
* length for a log string is defined to BUFSIZ, whose value depends on the
* system but typically is 4/8KB.
*/
int skygw_log_write(void* writebuf, logfile_id_t id, char* format, ...);
int skygw_log_write_flush(void* writebuf, logfile_id_t id, char* format, ...);
makefile.inc includes new CFLAG : SS_PROF, which is set if PROF=Y on make command line or in build_gateway.inc .
ss_debug.h includes corresponding ss_prof(exp) macro which equals to exp if SS_PROF is defined and to empty if in other case.
mlist_t now includes datadel function which is a callback and it is executed for mlnode_data on node exit.
skygw_logmanager_init is still useful because it allows for providing memory address for log manager where it can store a list of preallocated write buffers. TBD.
Logmanager access is now protected with spinlock familiar from epoll/core/spinlock.c . It is modified to avoid trashing; misses are counted and every tenth subsequent lock acquiring attempt triggers short random sleep.
