reegnz

CamelCase <--> snake_case conversion with jq

tl;dr

I provide you with 3 jq lib functions that will help you in converting between snake_case and CamelCase.

The interface

I want to change keys in my json from camelcase to snake_case.

reegnz

FROM ubuntu:focal

ENV DEBIAN_FRONTEND=noninteractive

RUN apt-get update \
	&& apt-get install -y eatmydata \
	&& eatmydata apt-get install -y \
    openjdk-11-jdk awscli azure-cli # just some big packages to notice the speedup \
	&& rm -rf /var/lib/apt/lists/*

reegnz

Terraform interface design: lists vs maps

The core problem

A lot of us have encountered this before: I need to create multiple instances of a resource, and we don't want to shoot ourselves in the foot with count, so we want to use for_each.

We define our input as a map of object, each key representing a resource instance. The key of the map will be the key of the resource in for_each.

reegnz

Using terraform for_each and toset instead of count

Using terraform count and the pain of working with it

If you're using terraform extensively you probably ran into an issue like this.

This is a synthetic example but I still hope the problem is recognizable as something that also happens out in the wild.

First, you have a list variable (in terraform.tfvars)

reegnz

Download kuttle:

wget https://raw.githubusercontent.com/kayrus/kuttle/master/kuttle
chmod +x kuttle
mv kuttle ~/bin

create tunnel:

reegnz

Implementing a jq REPL with fzf

Update: I created jq-zsh-plugin that does this.

One of my favourite tools of my trade is jq. It essentially enables you to process json streams with the same power that sed, awk and grep provide you with for editing line-based formats (csv, tsv, etc.).

Another one of my favourite tools is fzf.

reegnz

Emulating Terraform Module for_each

tl;dr

We want to create n resources, and 1:m relationships to each of these resources. In the end we expect n + n*m resources to be created.

Running the example:

reegnz

Keybase proof

I hereby claim:

• I am reegnz on github.
• I am reegnz (https://keybase.io/reegnz) on keybase.
• I have a public key ASDBlhbcI0bttXoW_f8SOg86X51luqkFqD6uoNojYPHpgwo

To claim this, I am signing this object:

reegnz

#! /bin/bash

# An overly obvious reference for most commonly requested bash timestamps
# Now all you Mac fags can stop pestering me.

cat << EOD
        Format/result         |       Command              |          Output
------------------------------+----------------------------+------------------------------
YY-MM-DD_hh:mm:ss             | date +%F_%T                | $(date +%F_%T)
YYMMDD_hhmmss                 | date +%Y%m%d_%H%M%S        | $(date +%Y%m%d_%H%M%S)