Technical Musings: January 2015

Tuesday, January 6, 2015

'Compressing' CloudFormation template to get around size limit

Recently I hit the 51,200 byte body size limit of AWS's CloudFormation's templates.  I looked into creating Nested Stacks, but that seemed like a pain.  Looking at the created json template, I saw a lot of unneeded whitespace.

I used troposhere to generate the template, so it was easy to reduce the size by stripping out the beginning and ending whitespace of each line in the json file.

I just added the following line:
json_compressed="\n".join([line.strip() for line in t.to_json().split("\n")])

This more than havled the size of the template from ~60K to ~25K bytes:

$ wc template.json
    1821    2860   60133 template.json

$ wc template_compressed.json
    1821    2860   24616 template_compressed.json

And CloudFormation accepted it, no problem.

Friday, January 2, 2015

Elixir Tgraph

In my attempt to learn Elixir, I've converted an Erlang version of a Python script I wrote years ago.  It takes a pipe of numeric values and plots lines in a character terminal.  Super simple, but handy sometimes.

Now, I know line count is a horrible way to compare code, but here it is:

136 tgraph.escript
106 tgraph.ex

The python code is many years old.  Maybe I've learned something since then, but I don't write very compactly, on purpose.  I only use standard libraries since I don't have the luxury of installing stuff on some of the systems I want to run this on, so can't use some of the cool libraries out there.

It's hard to compare the python code to the Erlang/Elixir.

The Erlang code has added cruft on top to run as Escript (so I don't have to compile changes).   I've yet to figure how to enable piping of stdin to Elixir without running a build ('mix').  So I get to compile my interpreted code!

Otherwise, the Elixir code is easier to read and more concise than Erlang, which is no suprise.  Elixir +1.