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".
The soname version numbers were missing from all the library targets
properties which caused ldconfig to warn about non-symlink libraries
being installed.
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.
Since localtime is not thread-safe it should not be used in multithreaded
contexts. For this reason all calls to localtime were changed to localtime_r
in code where concurrency issues were possible.
Internal tests were left unchanged because they aren't multithreaded.
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 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.
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.
