Thomas Kim Pham thpham

FWIW: I (@rondy) am not the creator of the content shared here, which is an excerpt from Edmond Lau's book. I simply copied and pasted it from another location and saved it as a personal note, before it gained popularity on news.ycombinator.com. Unfortunately, I cannot recall the exact origin of the original source, nor was I able to find the author's name, so I am can't provide the appropriate credits.

Effective Engineer - Notes

By Edmond Lau
Highly Recommended 👍
http://www.theeffectiveengineer.com/

What's an Effective Engineer?

Applied Functional Programming with Scala - Notes

1. Mastering Functions

A function is a mapping from one set, called a domain, to another set, called the codomain. A function associates every element in the domain with exactly one element in the codomain. In Scala, both domain and codomain are types.

val square : Int => Int = x => x * x

	#cloud-config

	# Set the hostname for this machine (takes precedence over hostname assigned by DHCP lease).
	hostname: myhost
	# Authorize SSH keys for the `rancher` sudoer user
	ssh_authorized_keys:
	- ssh-rsa AAA...ZZZ example1@rancher

	systemd = {
	services = {
	"macchanger-wireless" = {
	description = "Changes MAC of my wireless interface for privacy reasons";
	wants = [ "network-pre.target" ];
	wantedBy = [ "multi-user.target" ];
	before = [ "network-pre.target" ];
	bindsTo = [ "sys-subsystem-net-devices-wlp3s0.device" ];
	after = [ "sys-subsystem-net-devices-wlp3s0.device" ];
	script = ''

	# This isn't meant to be ran as a script, but line-by-line
	# Props to Binary (benary.org) for helping me with this

	# 0: Create a Scaleway instance and SSH into it
	ssh root@...

	# 1: Install Nix
	adduser user # set a password, doesn't matter what because it's not staying long
	adduser user sudo
	su -l user

	#!/usr/bin/env python

	from xivo_auth_client import Client as Auth
	from xivo_confd_client import Client as Confd

	auth = Auth('127.0.0.1', username='sylvain', password='sylvain', verify_certificate=False)

	token_data = auth.token.new('xivo_user', expiration=10)
	token = token_data['token']
	uuid = token_data['xivo_user_uuid']

	#!/bin/bash

	export PATH=/usr/local/bin:/bin:/usr/bin:/usr/local/sbin:/usr/sbin:/sbin
	docker_pid=$(cat /var/run/docker.pid)
	gdb -p $docker_pid <<< "$( ls /proc/$docker_pid/fd -l --time-style=+'%s' \| grep -E 'deleted' \| awk '{ printf("p close(%s)\n", $7)}')" >/dev/null


	#closing evenfds that do not have a corresponding memory.oom_control
	eventfds="$(for eventfd in $(ls /proc/$docker_pid/fd -l --time-style=+'%s' \| grep -E 'eventfd'\| awk '{print $7}'); do
	memory_pid=$((eventfd - 1))

	#!/bin/bash
	# This checks which ports haproxy currently is listening on, temporarily drops SYN packets
	# to prevent new connections, reloads haproxy, then allows SYNs again.
	#
	# Based on info from here:
	# * https://github.com/aws/opsworks-cookbooks/pull/40
	# * http://www.mail-archive.com/[email protected]/msg06885.html

	#set -x

	#!/bin/bash

	source /etc/environment
	hostname=$(cat /etc/machine-id)
	machines=$(etcdctl ls /consul.io/bootstrap/machines)

	#If there are 'machines' then the cluster has been initialised.
	if [ -z "$machines" ]
	then
	flags="${flags} -bootstrap"

	To get started with Docker/Marathon/Mesos, you need to install a
	new Mesos, a new Marathon, and Deimos, the bridge to Docker.
	You'll also need Docker and the JVM. These instructions are for
	Ubuntu 13.10.

	## Install Mesos prerequisites
	:; sudo apt-get update
	:; sudo apt-get install zookeeperd default-jre python-setuptools python-protobuf curl pip

	## Install recent Mesos