How to make Apache logfiles accessible to shared hosting users in real-time

In case you'r running a logrotate, which also sets the permissions of the new log files, that might be a good place to make the change. For example, this is a default apache2 logrotate on an Ubuntu server.

andreas@halleck:~$ sudo cat /etc/logrotate.d/apache2
/var/log/apache2/*.log {
    weekly
    missingok
    rotate 52
    compress
    dateext
    delaycompress
    notifempty
    create 640 root adm
    sharedscripts
    postrotate
        if [ -f "`. /etc/apache2/envvars ; echo ${APACHE_PID_FILE:-/var/run/apache2.pid}`" ]; then
            /etc/init.d/apache2 reload > /dev/null
        fi
    endscript
}

As you see there is a setting called create? Feel free to change it to whatever mode and ownership you want new log files to have. Also, here is how the create option is described in the logrotate(8) man file.

create mode owner group

Immediately after rotation (before the postrotate script is run) the log file is created (with the same name as the log file just rotated). mode specifies the mode for the log file in octal (the same as chmod(2)), owner specifies the user name who will own the log file, and group specifies the group the log file will belong to. Any of the log file attributes may be omitted, in which case those attributes for the new file will use the same values as the original log file for the omitted attributes. This option can be disabled using the nocreate option.

That's what I did:

1. chown user_name:www-data website_dir
2. chmod g+s website_dir # this makes new files/directories in that catalog owned by www-data user (standard Debian webserver user)
3. Then any user-created file that's group-readable can be accessed by webserver, and user can do chmod g+w if they want directory/file to be also writable by webserver (like configs/upload etc)

Downside of that is that user www-data runs all the scrips so user can get another user data using php/ruby/perl/whatever is run on webserver.

Next step would be using something like mod_suphp or mod_suexec to run user scrips with privledges of that user.