jpluscplusm

#!/usr/bin/awk
# 1-liner: awk '{for(i=0;i<4;i++){byte=$1%256;ip="." byte ip;$1-=byte;$1/=256}}END{sub(".","",ip);print ip}'   

{
  for(i=0; i<4; i++) {
    byte = $1 % 256
    ip = "." byte ip
    $1 -= byte
    $1 /= 256
  }

jpluscplusm

Nginx Double A

A primitive Double A (AAA-minus-Accounting) RBAC system implemented in declarative Nginx config.

Background

So I noticed https://github.com/alexaandru/elastic_guardian, a simple AAA reverse-proxy to sit in front of Elasticsearch. Reading the source and comments tickled my "why is this in code not config?" funnybone.

I asked @alexaandru (https://twitter.com/jpluscplusm/status/438339557906735104) who told me it was mostly the resulting complexity of the nginx config he tried that prompted him to write it.

jpluscplusm

server {
  listen [::]:80;
  listen 80;
  server_name "~^(?<thishost>[^.]+.)?(subdomain.example.com)$";
  access_log off;

  location / {
    resolver 8.8.8.8; # or whatever your server can use
    sub_filter_once off;
    sub_filter 'thepiratebay.se' 'subdomain.example.com';

jpluscplusm

#!/usr/bin/env bash
set -ueo pipefail

outofbandlogstring="This string must NEVER appear in the script's stdout/err ..." # or, like, simply "§" ...

function enter() {
  echo "$@"
  echo "${outofbandlogstring}+2"
}

jpluscplusm

BOSH Links: Why and How

Audience: anyone in the BOSH ecosystem, whether you work on something open-source or proprietary

"BOSH Links" is a feature which simplifies how data is shared between BOSH-deployed jobs that need to collaborate with one another (e.g. a web server and its backing database). Like many BOSH things, the whole "BOSH Links" thing can seem counter-intuitive at first, and it may not be clear why things are the way they are. This note hopes to show some of the powerful benefits of BOSH Links, and provide examples and explanations that make things more intuitive.

1. Why?
2. BASIC: A simple problem statement
3. BASIC: Putting the puzzle pieces together
4. ADVANCED: But what about...

jpluscplusm

#!/bin/bash

# vpnc-script wrapper for use with openconnect that routes all AWS IP ranges over the VPN.
# Pass any additional IP ranges to be routed as args to the script.
#
# Requirements: bash, curl and jq.
#
# Example usage:
# openconnect https://vpn.example.com/profile --script '/path/to/vpnc-script-aws'
#

jpluscplusm

setup() {
  # Global setup
  if [ $BATS_TEST_NUMBER -eq 1 ]; then
    {
      echo export FOO=bar
    } >${BATS_TMPDIR}/bats.import.$PPID
  fi
  . ${BATS_TMPDIR}/bats.import.$PPID

  # Per-test setup as per documentation

jpluscplusm

resource "aws_instance" "instance" {
  ami           = "ami-32rrg4334f"
  instance_type = "t2.small"
  subnet_id     = "subnet-abc123dasf"
  key_name      = "key"

  associate_public_ip_address = false

  vpc_security_group_ids = [
    "${aws_security_group.1.id}",

jpluscplusm

/.terraform/terraform.tfstate*
/plan.out
/.plan.out.*

jpluscplusm

#!/bin/bash
# ASCII-delimited input and output
awk -vFS="\x1F" -vRS="\x1E" -vOFS="\x1F" -vORS="\x1E" "$@"