Inkscape allows python scripts to be used as effects plugins. In a nutshell: you use the DOM to create / manipulate the structure of the SVG document and use CSS properties to style -- so there's quite some overlap with "regular" CGI & web programming.
This example (circles) is based on the example given on the Inkscape wiki. I started by making a simple Inkscape file (with a single circle), saving the file, then opened it in a text editor to view the "raw" XML structure of the SVG. I used this as a guide for what the code needed to produce.