Cute Tricks With Perl and Apache
    Author: Lincoln Stein <lstein@cshl.org> Date: 7/3/98

PART I: WEB SITE CARE AND FEEDING
    These scripts are designed to make your life as a Webmaster easier, leaving you time for more exciting
    things, like tango lessons.

  Logs! Logs! Logs!

    Left to their own devices, the log files will grow without limit, eventually filling up your server's
    partition and bringing things to a grinding halt. But wait! Don't turn off logging or throw them away. Log
    files are your friends.

    Script I.1.1 shows the basic script for rotating log files. It renames the current "access_log" to
    "access_log.0", "access_log.0" to "access_log.1", and so on. The oldest log gets deleted. Run it from a cron
    job to keep your log files from taking over. The faster your log files grow, the more frequently you should
    run the script.

    ---------------- Script I.1.1: Basic Log File Rotation ----------

     #!/usr/local/bin/perl
     $LOGPATH='/usr/local/apache/logs';
     @LOGNAMES=('access_log','error_log','referer_log','agent_log');
     $PIDFILE = 'httpd.pid';
     $MAXCYCLE = 4;

     chdir $LOGPATH;  # Change to the log directory
     foreach $filename (@LOGNAMES) {
        for (my $s=$MAXCYCLE; $s--; $s >= 0 ) {
            $oldname = $s ? "$filename.$s" : $filename;
            $newname = join(".",$filename,$s+1);
            rename $oldname,$newname if -e $oldname;
        }
     }
     kill 'HUP',`cat $PIDFILE`;

    -----------------------------------------------------------------

    But some people don't want to delete the old logs. Wow, maybe some day you could sell them for a lot of money
    to a marketing and merchandising company! Script I.1.2 appends the oldest to a gzip archive. Log files
    compress extremely well and make great bedtime reading.

    ---------- Script I.1.2: Log File Rotation and Archiving ---------

     #!/usr/local/bin/perl
     $LOGPATH    = '/usr/local/apache/logs';
     $PIDFILE    = 'httpd.pid';
     $MAXCYCLE   = 4;
     $GZIP       = '/bin/gzip';

     @LOGNAMES=('access_log','error_log','referer_log','agent_log');
     %ARCHIVE=('access_log'=>1,'error_log'=>1);

     chdir $LOGPATH;  # Change to the log directory
     foreach $filename (@LOGNAMES) {
       system "$GZIP -c $filename.$MAXCYCLE >> $filename.gz" 
            if -e "$filename.$MAXCYCLE" and $ARCHIVE{$filename};
        for (my $s=$MAXCYCLE; $s--; $s >= 0 ) {
            $oldname = $s ? "$filename.$s" : $filename;
            $newname = join(".",$filename,$s+1);
            rename $oldname,$newname if -e $oldname;
        }
     }
     kill 'HUP',`cat $PIDFILE`;

    -----------------------------------------------------------------

    What's that? Someone broke into your computer, stole your log files and now he's selling it to a Web
    marketing and merchandising company? Shame on them. And on you for letting it happen. Script I.1.3 uses
    *idea* (part of the SSLEay package) to encrypt the log before compressing it. You need GNU tar to run this
    one. The log files are individually compressed and encrypted, and stamped with the current date.