syslog

(PHP 4, PHP 5, PHP 7, PHP 8)

syslog — Erzeugt eine Meldung für das System-Log

Beschreibung

syslog(int $priority, string $message): true

Die Funktion syslog() erzeugt eine Log-Meldung, die über das System-Log ausgegeben wird.

Weitere Informationen zum benutzerdefinierten Loghandler sind unter syslog.conf (5) der Unix-Manpages zu finden. Zusätzliche Informationen zu den SysLog-Möglichkeiten und -Optionen sind in den Manpages zu syslog (3) (auf UNIX-Systemen) zu finden.

Parameter-Liste

priority

Der Parameter priority ist eine Kombination der System-Möglichkeiten und dem Level. Mögliche Werte sind:

**syslog()**-Prioritäten (in absteigender Reihenfolge)
Konstante	Beschreibung
`LOG_EMERG`	System ist unbrauchbar
`LOG_ALERT`	Sofortige Maßnahmen sind erforderlich
`LOG_CRIT`	Kritischer Zustand
`LOG_ERR`	Fehler aufgetreten
`LOG_WARNING`	Warnung aufgetreten
`LOG_NOTICE`	Normale, aber wichtige Meldung
`LOG_INFO`	Informative Meldung
`LOG_DEBUG`	Debug-Level-Meldung

message

Die zu sendende Nachricht.

Rückgabewerte

Gibt immer true zurück.

Beispiele

Beispiel #1 Die Verwendung von syslog()

<?php
// öffne SysLog, schließe die Prozess-ID (PID) ein, sende
// die Log-Meldungen an die Standard-Fehler-Ausgabe und benutze
// einen benutzerdefinierten Log-Mechanismus.
openlog("myScripLog", LOG_PID | LOG_PERROR, LOG_LOCAL0);

// etwas Code

if (authorized_client()) {
    // mache etwas
} else {
    // unerlaubter Client!
    // logge den Zugriff
    $access = date("Y/m/d H:i:s");
    syslog(LOG_WARNING,"Unautorisierter Client: $access "
        . "{$_SERVER['REMOTE_ADDR']} ({$_SERVER['HTTP_USER_AGENT']})");
}

closelog();
?>

Anmerkungen

Unter Windows wird der Syslog-Dienst emuliert, indem der Ereignis-Protokolldienst genutzt wird.

Hinweis:
Unter Windows können LOG_LOCAL0 bis LOG_LOCAL7 nicht für den Parameter facility von openlog() verwendet werden.

Siehe auch

openlog() - Stellt eine Verbindung zum Log-Dienst des Systems her
closelog() - Schließt die Verbindung zum System-Logger
INI-Einstellung syslog.filter (ab PHP 7.3)

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User Contributed Notes 18 notes

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stevekamerman at gmail dot com ¶

6 years ago


This function sends messages in BSD Syslog RFC 3164 format (https://tools.ietf.org/html/rfc3164).

To see the raw messages being sent by PHP to the logging socket, first stop your syslog/rsylsog/ng-syslog service, then listen to the logging socket with the netcat-openbsd package:

nc -U -l /dev/log

Now, log something from PHP:

<?php
syslog(LOG_LOCAL1|LOG_INFO, "Test from PHP");
?>

You will see the rfc3164 output from netcat:

<142>Oct 24 14:32:51 php: Test from PHP

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james dot ellis at gmail dot com ¶

16 years ago


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"

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Anonymous ¶

2 years ago


There's no point to manually timestamp the message (as shown in docs' example) as all sane logging systems timestamp all entries by themselves.

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OWM ¶

4 years ago


Syslog autodetects newline control characters and therefore splits the message by multiple lines. To prevent this behavior in PHP 7.3+ you can use undocumented (at this moment) ini setting:

<?php

ini_set('syslog.filter', 'raw');

# more info here: https://bugs.php.net/bug.php?id=77913

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Antonio Lobato ¶

14 years ago


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.

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rgagnon24 at gmail dot com ¶

5 years ago


This one had me going for a while when using LOG_ constants in another object, when developing on Windows, but deploying on Linux.

Windows evaluates some of the LOG_ constants to the same value, while LINUX does not.

The 8 constants and their differences on the platforms to be aware of:

Linux has these values as:
========================
LOG_EMERG = 0
LOG_ALERT = 1
LOG_CRIT = 2
LOG_ERR = 3
LOG_WARNING = 4
LOG_NOTICE = 5
LOG_INFO = 6
LOG_DEBUG = 7

While on Windows, you have:
==========================
LOG_EMERG = 1
LOG_ALERT = 1
LOG_CRIT = 1
LOG_ERR = 4
LOG_WARNING = 5
LOG_NOTICE = 6
LOG_INFO = 6
LOG_DEBUG = 6

So if you're setting LOG_WARNING in your code, Linux will use 4 as the priority while Windows will use 5.

This is not a bug in PHP on either platform, but a difference in the system header files that PHP compiles with.  Not really anything you can do, but be aware if you're wondering why your messages log at different priorities depending on the platform, this could be why.

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helly at php dot net ¶

17 years ago


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); };

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huangyg11 at gmail dot com ¶

9 years ago


For those who want to simultaneously write to multiple syslog facilities : 

syslog(LOG_INFO|LOG_LOCAL0, "message for local0");
syslog(LOG_INFO|LOG_LOCAL1, "message for local1");

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daniele dot patoner at biblio dot unitn dot it ¶

21 years ago


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();
?>

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mavetju at chello dot nl ¶

23 years ago


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");

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-1

antoine dot leverve dot EXT at zodiacaerospace dot com ¶

8 years ago


The documentation is incorrect when it says "Priorities (in descending order)", as the table that follows is actually in **ascending** order.

For example my output says:
LOG_ERR : 4
LOG_WARNING : 5
LOG_DEBUG : 6

An important difference, that caused me some pain!

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-1

gregj at pdxperts dot com ¶

21 years ago


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

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-2

dpreece at paradise dot net dot nz ¶

22 years ago


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

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-2

bb at lb-data dot co dot at ¶

25 years ago


In Windows NT, use the following values of priority:

1 = error,

6 = info

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-5

Torsten ¶

20 years ago


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.

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-4

rcgraves+php at brandeis dot edu ¶

24 years ago


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.

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-11

adam _at_ lockdownnetworks _dot_ com ¶

17 years ago


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.

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-14

gherson at snet dot net ¶

23 years ago


Example of where to look for syslog's output:   /var/log/httpd/access_log

(on Red Hat Linux Secure Server v6.2).

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