This weekend, I created library to aid developers in creating neat little embedded DSLs when using python, without having to do any complex parsing or anything like that. The resulting DSLs look a bit more like english than python does.

The idea for this was inspired by some ruby stuff that I’ve been using lately. I’ve been using ruby quite a bit lately, and while I am still not a huge fan of the language, I do like the idea of easy to code up DSLs that I can use to populate objects without too much effort. Since I wanted a DSL for a python project I was working on, I played with a few ideas and ended up with this tool. (more…)

I was just recently introduced to chef, and it has turned out to be a pretty useful tool for automating infrastructure. One feature that I’m using in our environment is chef environments. A bunch of developers are all updating this file, and their cookbooks depend on attributes in it*.  I keep getting bit by various user errors that all could be solved if a cookbook could state ‘make sure you have at least this version of the environment’.

I’m sure there’s a good reason for it, but chef does not currently support versioning environments. To work around this problem, I created a cookbook with a library function that can check a node attribute and compare the version information there to determine if the environment is out of date. It’s a bit of a hack for now, but it gets the job done.

I thought someone else might find this useful, so I uploaded the code to github and to the opscode community site. If you have a need for versioned environments in chef, this might work for you too. Let me know if you find it useful!

*Yes, this could be considered an anti-pattern, but for our use case using environments to override attributes makes perfect sense, and allows us to not have to fork every community cookbook that we want to use.