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Date Tue 27 November 2007

Since we moved into our apartment at the end of last summer, my roommates and I have had a Brother 5170DN monochrome laser in the hallway as a communal printer. Last weekend, two new printers arrived - I got a Xerox DocuPrint N4525 - a big surplus student lab printer that handles paper up to 11x17” and print rates of up to 45 PPM. My roommates picked up a (free!) HP Color LaserJet 4500. So, I decided that I want accounting of who prints what on each printer.

I setup a Dell PowerEdge 650 running openSuSE 10.3, Xen and 2 NICs, one on our main network and one with a static IP in a separate subnet hooked up to a small 5-port switch. I setup a Xen VM (also openSuSE 10.3) to act as a CUPS server. I then installed tea4cups which allows outgoing CUPS jobs to be read via a pseudo-backend while they’re processing. tea4cups calls some PHP scripts that update a MySQL database with job information, including page counts and ink coverage amounts calculated by pkpgcounter.

This is all done with a kludge of custom scripts, which I’ll put in my CVS repo (and comment on here) sometime this week.

I did run into two problems. First, I had issues with getting tea4cups to run at all. After googling a bit, I read about people having problems with tea4cups and SELinux. Sure enough, I disabled AppArmor and all went back to normal. Also, I later had some problems trying to perform ink accounting on a color printer. After some investigation, I also found out that GhostScript 8.15 is buggy and will cause problems with pkpgcounter. I upgraded to the 8.60 RPMs and all was well.

The whole project is still in the works, but when finished I should have a system that will keep track of all printing in the apartment by username and IP, and track the page count, paper size, color or B&W, resolution, and ink coverage percentage (both for grayscale and CMYK or RGB individually). I know it’s overkill - all I want to really know is enough data to fairly split the costs of paper, toner, etc. - but I thought it would be a fun project.

I originally thought about using PyKota for the accounting, but found it to be way too heavy-weight. My current kludge, done up in one night (before writing an essay), is based on CUPS and tea4cups, which calls PHP backend prehooks and posthooks, which in turn make use of a few pre-written python and perl scripts that deal with querying information from the printer (IPP) and local files.

All in all, for something that didn’t exist 24 hours ago, I think it’s working pretty well so far.

Update 2015-02-11: Someone (comments below) has found this and asked for further information. Sadly, I wrote this stuff eight years ago, and haven’t been running it in seven or so. I did manage to find the CVS repository in my backups, so I have some of the code. It’s certainly not functional or documented, but it should give you at least a general idea of how all this fits together. Be aware that there are some known issues, so I wouldn’t consider the data it gives (at least when it comes to ink usage) as more than a rough estimate. The original idea was to do print accounting for my roommates and I (being good geeks we had three printers including a color laser - a bit of a novelty at the time - and an 11x17” laser) so we could evenly split the bill when it came time to buy toner. The accounting code is PHP, and really bad PHP at that. There’s a a web interface, but unfortunately the database schema is long gone. I have no idea what versions of packages this was written for, but assume they could have been “old” versions in 2007. All that being said, assuming that tea4cups hasn’t changed too much since then, this should give you at least a general idea of how this all fit together and is possible.

The code that I have is available as a 35K .tar.gz archive here.


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