PHP 7.0.6 Released

    syslog

    (PHP 4, PHP 5, PHP 7)

    syslog — Generate a system log message

    Description

    bool syslog ( int $priority , string $message )

    syslog() generates a log message that will be distributed by the system logger.

    For information on setting up a user defined log handler, see the syslog.conf (5) Unix manual page. More information on the syslog facilities and option can be found in the man pages for syslog (3) on Unix machines.

    Parameters

    priority

    priority is a combination of the facility and the level. Possible values are:

    syslog() Priorities (in descending order)
    Constant Description
    LOG_EMERG system is unusable
    LOG_ALERT action must be taken immediately
    LOG_CRIT critical conditions
    LOG_ERR error conditions
    LOG_WARNING warning conditions
    LOG_NOTICE normal, but significant, condition
    LOG_INFO informational message
    LOG_DEBUG debug-level message

    message

    The message to send, except that the two characters %m will be replaced by the error message string (strerror) corresponding to the present value of errno.

    Return Values

    Returns TRUE on success or FALSE on failure.

    Examples

    Example #1 Using syslog()

    <?php
    // open syslog, include the process ID and also send
    // the log to standard error, and use a user defined
    // logging mechanism
    openlog("myScriptLog", LOG_PID | LOG_PERROR, LOG_LOCAL0);

    // some code

    if (authorized_client()) {
            // do something
    } else {
            // unauthorized client!
        // log the attempt
            $access = date("Y/m/d H:i:s");
            syslog(LOG_WARNING, "Unauthorized client: $access {$_SERVER['REMOTE_ADDR']} ({$_SERVER['HTTP_USER_AGENT']})");
    }

    closelog();
    ?>

    Notes

    On Windows NT, the syslog service is emulated using the Event Log.

    Note:

    Use of LOG_LOCAL0 through LOG_LOCAL7 for the facility parameter of openlog() is not available in Windows.

    See Also

    User Contributed Notes

    james dot ellis at gmail dot com
    8 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"
    Antonio Lobato
    5 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.
    helly at php dot net
    9 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); };
    huangyg11 at gmail dot com
    11 months 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");
    nospam \100 jraxis com (that's right!)
    14 years ago
    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.
    daniele dot patoner at biblio dot unitn dot it
    12 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();
    ?>
    antoine dot leverve dot EXT at zodiacaerospace dot com
    4 months 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!
    Torsten
    12 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.
    gregj at pdxperts dot com
    12 years ago
    The message string sent to the log file is limited to 500 characters.
    dpreece at paradise dot net dot nz
    14 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
    mavetju at chello dot nl
    15 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");
    rcgraves+php at brandeis dot edu
    16 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.
    bb at lb-data dot co dot at
    16 years ago
    In Windows NT, use the following values of priority:
    1 = error,
    6 = info
    adam _at_ lockdownnetworks _dot_ com
    9 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.
    gherson at snet dot net
    15 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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