syslog

Antonio Lobato (2010-05-11 13:57:16)

A word of warning; if you use openlog() to ready syslog() and your Apache threads accept multiple requests, you *must* call closelog() if Apache's error log is configured to write to syslog.  Failure to do so will cause Apache's error log to write to whatever facility/ident was used in openlog.

Example, in httpd.conf you have:

ErrorLog syslog:local7

and in php you do:

<?php
openlog("myprogram", 0, LOG_LOCAL0);
syslog("My syslog message");
?>

From here on out, this Apache thread will write ErrorLog to local0 and under the process name "myprogram" and not httpd!  Calling closelog() will fix this.

james dot ellis at gmail dot com (2007-12-02 20:26:35)

If anyone is wondering why their log messages are appearing in multiple log files, here is one answer applying to *nix systems:
If your syslog.conf looks like this (assuming you use LOG_LOCAL0 for web app logging) :
local0.info /var/log/web/info.log
This will collect *all* messages of LOG_INFO level and higher, i.e everything except debug messages
Try this instead to ensure that only messages of the named log level go into the relevant log file:
local0.=info /var/log/web/info.log
Additionally, you may like to add this to ensure your messages don't end up in generic log files like "messages" "all" "syslog" and "debug":
local0.none /var/log/messages
local0.none /var/log/debug
etc
saves disk space among other things - more at "man syslog.conf"

helly at php dot net (2007-04-13 05:49:15)

If you are using syslog-ng and want errors send to syslog then use ini setting "error_log = syslog" and add something like the following to your syslog-ng.conf:
destination php { file("/var/log/php.log" owner(root) group(devel) perm(0620)); };
log { source(src); filter(f_php); destination(php); };

adam _at_ lockdownnetworks _dot_ com (2007-04-10 18:32:04)

Be aware when using syslog() that if you set the timezone of environment to be something other than the standard, syslog() may log the time to the log(s) with the wrong time zone information. For example:

<?php

openlog('mylog', LOG_PID | LOG_ODELAY,LOG_LOCAL4);

putenv('TZ=UTC');
syslog(LOG_INFO, 'UTC Log line');

putenv('TZ=US/Pacific');
syslog(LOG_INFO, 'US/Pacific Log line');

closelog();

?>

Viewing the /usr/log/messages log will display these two lines:

Apr 11 01:25:39 hostname mylog[1400]: UTC Log line
Apr 10 18:25:39 hostname mylog[1400]: US/Pacific Log line

Adam.

Torsten (2004-04-23 06:27:15)

I had a problem trying to issue a syslog message with IIS 5.1 under Windows XP. The function call seemed to succeed, but the event viewer showed that no entry was made.
Finally I found out that the user account used for the webserver (IUSR_<Computername>) did not have enough permissions to issue syslog alerts. I changed this by adding this user to the Users group instead of only Guest.

daniele dot patoner at biblio dot unitn dot it (2003-11-06 11:00:31)

This work for me, to redirect  logs to a separate syslog file

put this line in your /etc/syslog.conf :

local0.debug   /var/log/php.log

Then restart syslogd:

/etc/init.d/syslog restart

php example:

<?php
define_syslog_variables();
openlog("TextLog", LOG_PID, LOG_LOCAL0);

$data = date("Y/m/d H:i:s");
syslog(LOG_DEBUG,"Messagge: $data");

closelog();
?>

gregj at pdxperts dot com (2003-07-28 17:05:58)

The message string sent to the log file is limited to 500 characters.

monte at ispi dot net (2003-07-03 11:05:07)

If you have php.ini setup to send PHP errors to syslog, they will all get dumped into /var/log/messages (at least it does with RedHat 9 by default). I wanted to figure out how to get PHP errors to go to their own syslog file.
After some trial and error, I figured out what facility and priority PHP uses, which is "user.notice". So, to get your PHP errors going to a separate syslog file, put this line in your /etc/syslog.conf :
user.notice /var/log/php.log
Then restart syslogd:
/etc/init.d/syslog restart
Why PHP uses "user" as the facility I'm not sure, probably because it's the only one that works under Windows?
Monte

nospam \100 jraxis com (that's right!) (2002-03-31 08:32:42)

This *does* actually goto the system log as configured in /etc/syslog.conf (such as /var/log/messages), it doesn't goto Apache's ErrorLog (such as /var/log/httpd/error_log). At least under my Debian Potato with Apache 1.3.23.
Use error_log() to be sure it gets into Apache's ErrorLog.

dpreece at paradise dot net dot nz (2002-01-29 16:08:41)

To set up a custom log file via the syslog daemon (FreeBSD in this case)...
Add to /etc/syslog.conf a line that says all errors from the httpd process are to go to a file called (for example) /var/log/httpd-php.log
!httpd
*.* {tab} /var/log/httpd-php.log
Note the tab, being a tab character! Next create a blank file to be written to. I'm sure there are 1e+6 ways to do this, but I choose
# cat > httpd-php.log << EOF
? EOF
Finally find your syslog daemon and send it a sighup to inform it of the change:
# ps ax | grep syslogd
133 ?? Ss 0:07.23 syslogd -s
# kill -1 133
Et voila! Php syslog calls will now arrive in /var/log/httpd-php.log

mavetju at chello dot nl (2001-01-22 06:11:44)

With FreeBSD I can use: syslog(LOG_INFO,"test");
BSD/OS does not support this, I had to use the literal values for the priority (158: local3.info):
syslog(158,"test");

gherson at snet dot net (2000-12-20 13:09:26)

Example of where to look for syslog's output: /var/log/httpd/access_log
(on Red Hat Linux Secure Server v6.2).

rcgraves+php at brandeis dot edu (2000-02-17 00:51:53)

For the-header-file-enabled:
man 3 syslog defines the priorities, but not the integer values. For that you'll need to read your system header file.
Let's suppose I want to log an informational message in the mail log (which happens to be true). The man page tells me I want LOG_MAIL|LOG_INFO. So I look in /usr/include/sys/syslog.h and find (this happens to be Linux, your system could be different):
#define LOG_INFO 6 /* informational */
#define LOG_MAIL (2<<3) /* mail system */
2<<3 means shift 3 bits left, which means multiply by 8. So I want 2*8 + 6 = 22. syslog(22,"this message will appear in the mail log"); And indeed it does.

bb at lb-data dot co dot at (1999-09-08 03:54:13)

In Windows NT, use the following values of priority:
1 = error,
6 = info