Pros and cons for different configuration formats?

Question

I\'ve seen people using *.cfg (Python Buildout), *.xml (Gnome), *.json (Chrome extension), *.yaml (Google App Engine), *.ini and even *.py for app configuration files (like Djan

Answer 1

It's mostly personal preference, purpose, and available libraries. Personally I think xml is way too verbose for config files, but it is popular and has great libraries.

.cfg, .ini are legacy formats that work well and many languages have an included library that reads them. I've used it in Java, Python, C++ without issues. It doesn't really work as a data interchange format and if I am passing data I will probably use the same format for config and data interchange.

yaml, and json are between xml and cfg/ini. You can define many data structures in both, or it can be a simple key-value like with cfg. Both of these formats have great libraries in python and I'm assuming many other languages have libraries as well. I believe json is subset of yaml.

I've never used a python file as config, but it does seem to work well for django. It does allow you to have some code in the config which might be useful.

Last time I was choosing a format I chose yaml. It's simple but has some nice features, and the python library was easy to install and really good. Json was a close second and since the yaml library parsed json I chose yaml over it.