glaznaj

Running redis using upstart on Ubuntu

I've been trying to understand how to setup systems from the ground up on Ubuntu. I just installed redis onto the box and here's how I did it and some things to look out for.

To install:

Why objects (usually) use less memory than arrays in PHP

This is just a small post in response to [this tweet][tweet] by Julien Pauli (who by the way is the release manager for PHP 5.5). In the tweet he claims that objects use more memory than arrays in PHP. Even though it can be like that, it's not true in most cases. (Note: This only applies to PHP 5.4 or newer.)

The reason why it's easy to assume that objects are larger than arrays is because objects can be seen as an array of properties and a bit of additional information (like the class it belongs to). And as array + additional info > array it obviously follows that objects are larger. The thing is that in most cases PHP can optimize the array part of it away. So how does that work?

The key here is that objects usually have a predefined set of keys, whereas arrays don't:

PSQL

Magic words:

psql -U postgres

Some interesting flags (to see all, use -h or --help depending on your psql version):

-E: will describe the underlaying queries of the \ commands (cool for learning!)
-l: psql will list all databases and then exit (useful if the user you connect with doesn't has a default database, like at AWS RDS)

The introduction to Reactive Programming you've been missing

(by @andrestaltz)

This tutorial as a series of videos

If you prefer to watch video tutorials with live-coding, then check out this series I recorded with the same contents as in this article: Egghead.io - Introduction to Reactive Programming.

HTTP Streaming (or Chunked vs Store & Forward)

The standard way of understanding the HTTP protocol is via the request reply pattern. Each HTTP transaction consists of a finitely bounded HTTP request and a finitely bounded HTTP response.

However it's also possible for both parts of an HTTP 1.1 transaction to stream their possibly infinitely bounded data. The advantages is that the sender can send data that is beyond the sender's memory limit, and the receiver can act on

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/

	package main

	import (
	"bytes"
	"encoding/hex"
	"flag"
	"fmt"
	"io"
	"log"
	"net"

	requests.put('http://localhost:9200/site/', data=json.dumps({
	'settings': {
	'analysis': {
	'analyzer': {
	'ru': {
	'type': 'custom',
	'tokenizer': 'standard',
	"filter": ['lowercase', 'russian_morphology', 'english_morphology', 'ru_stopwords'],
	},
	},

	Ansible playbook to setup HTTPS using Let's encrypt on nginx.

	The Ansible playbook installs everything needed to serve static files from a nginx server over HTTPS.
	The server pass A rating on [SSL Labs](https://www.ssllabs.com/).

	To use:
	1. Install [Ansible](https://www.ansible.com/)
	2. Setup an Ubuntu 16.04 server accessible over ssh
	3. Create `/etc/ansible/hosts` according to template below and change example.com to your domain
	4. Copy the rest of the files to an empty directory (`playbook.yml` in the root of that folder and the rest in the `templates` subfolder)

	#!/bin/bash

	# Copyright 2017 Théo Chamley
	# Permission is hereby granted, free of charge, to any person obtaining a copy of
	# this software and associated documentation files (the "Software"), to deal in the Software
	# without restriction, including without limitation the rights to use, copy, modify, merge,
	# publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons
	# to whom the Software is furnished to do so, subject to the following conditions:
	#
	# The above copyright notice and this permission notice shall be included in all copies or