The Cacti Integration module provides an interface to query Drupal for statistics and return the results to the open source Cacti network graphing package. The use case is that you would like to create ongoing graphs of statistics of your Drupal site, such as how many authenticated and unauthenticated users are on the site.
The statistical data goes one way: from Drupal to Cacti. All templates, information, and graphs appear within the Cacti interface. It does not allow you to embed or otherwise 'bring back' information from Cacti to Drupal. It's a one way trip.
Currently tested with Cacti 0.8.7f and later. It may work with older revisions or you may need to modify the Cacti templates appropriately.
Current Status
This is nearly ready for general usage, and a dev version with the server, client, and a sample template has been committed. I'd love to have a few testers.
TODO: Create hookable system for adding new data queries from other modules.
Architecture
There are multiple pieces to making this all work. Here they are.
This module reads and parses your Amazon S3 account's various log files, so you can easily track your most popular uri's, and how much bandwidth has been used per-file. It also makes sure to never download the same log file twice (saving you bandwidth), and can be configured to only check for new log files every few hours (saving you GET and LIST requests).
This module encrypts the user's password when they type it in during login, so a 3rd party up to no good can't see the user's plain text password (as is currently the case with Drupal logins).
Encryption is accomplished by replacing what the user enters for their password with a uniquely-salted MD5 hash of the MD5 hash of what they typed (so it is 2-layers deep). If the user does not have JavaScript enabled, then the default Drupal behavior (no hashing) still works.
Of course, this is no substitute for an SSL certificate on your server, as that would protect all form submissions, as well as prevent other types of attacks. This module is intended for those who desire password security, but either cannot afford a certificate, or only need basic protection from hackers during login.