Since there is but one log file where error, warning, notice, info
and debug messages are written, calling it "error.log" is misleading.
Consequently the log file is renamed to "maxscale.log".
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.
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.
The value of global variables that can change copied before being
accessed to ensure that the used value is the same for the duration
of a function call. No locks are needed, because even if the copying
would not be atomic, it doesn't matter since all that matters is that
the used value does not change for the duration.
The string given to logmanager_write_log cannot be NULL.
The id given to logmanager_write_log cannot be invalid.
Consequently we need not handle those possibilities.
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 possibility for explicitly specifying the names
of the log files has never been used. In the name of simplicity
that functionality is removed.
Some log manager refactoring to make it easier to later remove
all files but the error log.
Basically all that was done was to move everything inside the
for-loop of thr_filewriter_fun into a separate function called
thr_flush_file. Otherwise no changes in functionality was made.
logmanager_write_log did three different things - logged a message,
flushed a file and rotated a file - none of which were performed
in one go. Hence there's no reason to do all those things in that
function.
Another step on the road of log manager modifications.
- All messages are now logged to error.log. The other files are
still created but not used anymore.
- A severity prefix is added, to distinguish between messages logged
to "different" files:
LOGFILE_ERROR => "[Error]: "
LOGFILE_MESSAGE => "[Notice]: "
LOGFILE_TRACE => "[Info]: "
LOGFILE_DEBUG => "[Debug] "
That prefix is not written to syslog.
- When maxscale is built in debug mode, trace and debug messages
are no longer enabled by default.
Next step is to remove the other files entirelly.
Valist is handled before logmanager_write_log is called. So it
is quite unnecessary to always having to pass a valist whether
it is used or not (and not it is never used).
Augmentation moved to skygw_log_write_context. The severity prefix
will be added there as well. If all is done on that level, the
amount of memory needed can be figured out in one go. No need to
allocate and copy the message several times.
