There were some variance regarding the way the MaxScale log (i.e.
the file log) was called; "maxlog" in configuration file and
"maxscalelog" at the command line and maxadmin interface. Now it
is uniformly referred to as "maxlog" in the configuration file, at
the command line, from maxadmin and in the code.
The earlier log file based approach for enabling and disabling
messages has now been completely replaced with the syslog priority
based approach.
Similarly as with log files before it is now possible to enable
and disable a log priority for a particular session, even though
it apparently has not been used much.
The local test-programs of the logging has got minimal attention
only to make them compile. They should get an overhaul as they did
not work before either.
Maxadmin earlier gave the impression that you could change whether
messages for different log files could be specifically enabled for
a session. In practice that was true only for trace messages as the
session id and the bitmask telling what logfiles are enabled, were
copied to thread local storage only as far as trace messages were
concered.
The code for setting that information in place is quit short and
efficient, so there is really no reason not to do that always.
This also means that it always will be possible to get your hands
on the session object if there is a need for that.
skygw_[enable|disable]_log has now been removed from the external
interface and priorities must instead be set using
mxs_log_set_priority_enabled(int priority, bool enabled). A bitmask
is already being updated, but internally and as used by the LOG_IF
macros, the actual enabling is still made using logfile ids.
The configuration entries have been replaced as follows:
log_messages -> log_notice
log_trace -> log_info
The old ones can be used, but cause a warning to be logged.
Similarily the maxadmin commands have been updated.
"[enable|disable] log ..." works as expected, but there will be
a message about it being deprecated. Instead there is now a
[enable|disable] log-priority err|warning|notice|info|debug
command that should be used instead.
skygw_logmanager_init renamed to mxs_log_init and skygw_logmanager_done
renamed to mxs_log_finish. skygw_logmanager_exit removed alltogether as
all it did was to call skygw_logmanager_done. That appears to have been
a source for confusion as in many places a call to skygw_logmanager_done
was followed by a call to skygw_logmanager_exit. In addition, the function
skygw_log_done was removed from the header, since it lacked an
implementation.
With only one log-file no arguments are needed. The maxadmin command
'flush log' still accepts all the previous arguments, but warns about
them being deprecated.
The native way for logging is now by syslog priority and not by
logfile id. In practice that means that there's a function -
mxs_log_message - that takes a syslog priority. The new logging
macros (MXS_ERROR and friends) call that directly and the old
ones as well after having the logfile id translated into the
equivalent priority.
What is enabled or not is still by logfile id and hence the
priority is internally translated into a logfile id when checking
whether something really should be logged or not.
Earlier, the global setting for the syslog decided whether syslog
was enabled when skygw_logmanager_init was called, but not whether
logging to syslog actually was made.
Now syslog logging is enabled by default and the global setting
decides whether or not syslog logging actually is made. That is,
this opens up the possiblity for making it possible to turn on
and off sysloging at runtime.
Further, although the API led you to believe otherwise, it was
hardwired that LOGFILE_ERROR and LOGFILE_MESSAGE messages were
written to syslog.
The changed removed the need for passing an argv array explicitly.
The syslog ident must be provided explicitly when calling
skygw_logmanager_init (and not provided via the argv array).
It can be NULL, in which case it automatically will be the program
name.
The openlog() call is now always made, irrespective of what the
value of the global syslog flag is. That way it will be possible
to turn syslog logging on or off after the fact.
Whether the log-file should be written to the filesystem or to
shared memory must now be explicitly defined when calling
skygw_logmanager_init() (instead of passing that via the argc/argv
construct).
Also, the meaning of '-l' when invoking maxscale has been changed.
Earlier -l [file|shm] specified whether the trace and debug logs
should be written to shared memory (while the error and message
logs always were written to the filesystem) and the _default_
was to write them to shared memory.
Now, with only one file, '-l' has still the same meaning, but it
decides whether the one and only logfile should be written to shared
memory, or the filesystem and the _default_ is to write it to the
filesystem.
If the log manager has not been inited, then messages are written
to stdout. In practice this can happen if something is directly or
indirectly logged during the startup of maxscale, before
skygw_logmanager_init() has been called. Some refactoring is needed
to allow skygw_logmanager_init() to be called very early at program
startup.
The previous interface of skygw_logmanager_init was conceptually
broken. With -o you could specify that logging should be done to
stdout. However, even if you did that, the log manager still checked
that the logging directory could be accessed. Unless it had been
specified using -j <path> the default was /var/log/maxscale.
That is, unless the program calling skygw_logmanager_init was invoked
by a user that had write access to /var/log/maxscale, there would be
a complaint even if nothing was ever written to that directory.
In practice this meant that even if -o was used you had to provide
a -j with a path that surely is writeable (e.g. "/tmp").
This has now been changed so that you explicitly must provide the
log directory and the flags -j and -o are removed.
bool skygw_logmanager_init(const char* logdir, int argc, char* argv[]);
If /logdir/ is provided then logged messages are written to a log file
in that directory. If /logdir/ is NULL then messages are logged to stdout
and no checks for access to any directory is not made.
The log manager variables lm_enabled_log_files_bitmask, log_ses_count
and tls_log_info that earlier were declared separately in every
c-file are now declared in the log_manager.h header.
The log manager possibility for explicitly specifying the names
of the log files has never been used. In the name of simplicity
that functionality is removed.
This commit is only to introduce new logging macros.
The current implementation is such that a statement like:
MAXSCALE_NOTICE("Refreshing configuration following SIGHUP\n");
is equivalent with
LOGIF(LM, (skygw_log_write(
LOGFILE_MESSAGE,
"Refreshing configuration following SIGHUP\n")));
The actual implementation will later be changed as the logging
mechanism itself is changed.
The names of the macros are now according to the levels of syslog
and currently the mapping is like:
MAXSCALE_ERROR (Syslog LOG_ERR) -> LOGFILE_ERROR
MAXSCALE_WARNING (Syslog LOG_WARNING) -> LOGFILE_ERROR
MAXSCALE_NOTICE (Syslof LOG_NOTICE) -> LOGFILE_MESSAGE
MAXSCALE_INFO (Syslog LOG_INFO) -> LOGFILE_TRACE
MAXSCALE_DEBUG (Syslog LOG_DEBUG) -> LOGFILE_DEBUG
When log manager is changed to deal "natively" with syslog levels
this mapping will disappear of course.
Straightforward indentation and whitespace modifications.
This is the first one in a series of commits that will bring
log manager in line with the coding style.
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;
