Mug

Print accounting software for CUPS (a replacement to Pykota)

Features

Mug provides users with the ability to...

Control the passage of print jobs to printers using a custom CUPS backend
Manage user quotas through a comprehensive and self-documented CLI (--help arguments provide all context needed to use the CLI)
Consolidate deployment and management of a print server through the use of secured containerization technologies (namely rootless podman and standardized OCI images).

Getting Started

Makefile contains most quickstart steps necessary for getting a rudimentary CUPS server with Mug installed working. Podman has been chosen as the container runtime for this application and is able to run this application as an unprivileged user, an important feature considering the requirements to run certain CUPS components as root.

Creating the CUPS + Mug Environment

make build will create the necessary OCI images that will be used to run the CUPS server and Mug software. This comes without Mug installed by default.

make start will start the containers using the OCI images built from the make build step. CUPS will begin listening on port 631.

make install will install the Mug software into the CUPS environment.

Ensure that you have installed the Python requirements necessary to build Mug (located in requirements.txt). This may be made into its own containerized build process in the future (TODO) but for now can be accomplished with a simple virtual environment.

Initializing the Mug Environment

Before moving forward with printing from the CUPS server, we need to

TODO: show how to create a db and add users to it

Testing Things Out

After we have created our Mug database and initialized it with a user, we can start printing!

make print provides a test PDF that can

Current Limitations

PDF Only

Currently, Mug is limited to being able to print PDFs only. This will be broadened in the future, making use of CUPS existing extensive filter framework. Newer versions of CUPS will deprecate filters, backend, and PPDs in favor of creating printer applications, which also have the limitation of preferring PDFS, though it seems that existing filter workflows can be preserved by encapsulation in a printer application, as demonstrated in this blog post by OpenPrinting.

No Group Policies

Currently, quotas are only enforced on a user-by-user basis. This means that the status attribute of accounts in Mug are not currently utilized, nor are the attributes associated with groups.

CUPS Administration Notes

To manually set PPD for printer in the case that the web GUI doesn't like Mug's device-uri:

lpadmin -P [PPDFilePath] -d [PrinterName]

Printers that have been paused (most likely due to a processing failure regarding a print job) can be resumed like so:

cupsenable [PrinterName]

TODO

Add build process for cups-pdf
Fix issue w/ cups-pdf not printing
Continue conversion of pkipplib (urllib2->3)
Determine page count by generating PDF and counting pages from PDF? (replacement for pkpgcounter)
Create stub backend (python script called mug) that invokes backend.py to prevent inconsistent file permissions

decaby7e/mug

Mug