Reusable CloudFormation Snippets with ERB

Amazon’s CloudFormation is a wonderful and flexible tool for provisioning and managing resources in an EC2 VPC. It really takes the concept of infrastructure-as-code and helps make it a reality. For all its flexibility though, it sacrifices intuitiveness and ease. It is also limited by the rigidity of JSON, which isn’t a full-fledged language so it doesn’t support variables (although Parameters, Mappings, and References to them are a long-winded and difficult to parse approach that comes close) or easily referencing reusable external libraries. It also isn’t possible to define arbitrary functions, iterate over lists, or define anything but the most rudimentary conditional sections. This is by no means a criticism of CloudFormation, as it has certainly done a lot to turn a serialization format into a pseudo scripting language, but these are my observations that might frustrate other people when using it.

That’s where ERB comes in. As a big advocate of Ruby, whenever I think of templating the first thing that comes to mind is ERB. A while back, I put together a super simple script that generates templates from JSON “layouts” and “snippets” (think views and partials from Rails), both of which fully support ERB and all of its Ruby goodness.
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Our Solar System

My five-year-old daughter is such a science nerd — I wonder where she gets it. She surprised me with a drawing she made for me, along with her ability to describe it with such fascination and detail. She informed me that she didn’t color the planets correctly but, and to paraphrase, she wanted to express some artistic freedom. I begrudgingly informed her that pluto is no longer considered a planet. I’m particularly happy that she managed to correctly draw rings on the four outer planets, though I couldn’t figure out if she did that because she knew that they all have rings. I mostly blame Bill Nye and the makers of the Magic School Bus for her knowing so much about space (maybe I’m a little to blame too). I only hope her passion for space and science continues. I’m so proud of my little girl. Our Solar System

Gamma

While I was watching a video from one of my favorite YouTube channels, I decided I wanted to try the math(s) that Professor Merrifield was describing to explain Gamma / the Lorentz factor. I’m very excited that my new blog supports \LaTeX and MathJax so the formulas actually turn out looking the way they should.

While this math might look difficult at first, it is really easy. It is essentially just using the Pythagorean theorem to isolate the relationship between t and \tau, which is the factor by which time (and length, and mass) changes for a moving object.

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