Thúlio Costa thulio

Latency numbers every programmer should know

L1 cache reference ......................... 0.5 ns
Branch mispredict ............................ 5 ns
L2 cache reference ........................... 7 ns
Mutex lock/unlock ........................... 25 ns
Main memory reference ...................... 100 ns             
Compress 1K bytes with Zippy ............. 3,000 ns  =   3 µs
Send 2K bytes over 1 Gbps network ....... 20,000 ns  =  20 µs
SSD random read ........................ 150,000 ns  = 150 µs

Read 1 MB sequentially from memory ..... 250,000 ns = 250 µs

Installing a Gem on Heroku from a Private GitHub Repo

Sometimes you want to use a gem on Heroku that is in a private repository on GitHub.

Using git over http you can authenticate to GitHub using basic authentication. However, we don't want to embed usernames and passwords in Gemfiles. Instead, we can use authentication tokens.

Get an OAuth Token from GitHub

First you will need to get an OAuth Token from GitHub using your own username and "note"

Guide to how fucked is SSL?

Thanks to Jacob Kaplan-Moss, Donald Stufft, David Reid, Allen Short, Zain Memon, and Chris Armstrong for review.

This is a guide for technical individuals to understand in what circumstances SSL communications are secure against an observer-in-the-middle (for all intents and purposes: the NSA).

Validação para cartão de crédito.

Bin e padrões para validação de cartão de crédito.

Bandeira	Começa com	Máximo de número	Máximo de número cvc
Visa	4	13,16	3
Mastercard	5	16	3

Set up a Spree backend only install

rails new store-backend

Gemfile

gem 'spree_backend', github: 'spree/spree'

	#!/usr/bin/env bash
	# memusg -- Measure memory usage of processes
	# Usage: memusg COMMAND [ARGS]...
	#
	# Author: Jaeho Shin <[email protected]>
	# Created: 2010-08-16
	############################################################################
	# Copyright 2010 Jaeho Shin. #
	# #
	# Licensed under the Apache License, Version 2.0 (the "License"); #

	#!/bin/sh

	###
	# SOME COMMANDS WILL NOT WORK ON macOS (Sierra or newer)
	# For Sierra or newer, see https://github.com/mathiasbynens/dotfiles/blob/master/.macos
	###

	# Alot of these configs have been taken from the various places
	# on the web, most from here
	# https://github.com/mathiasbynens/dotfiles/blob/5b3c8418ed42d93af2e647dc9d122f25cc034871/.osx

	<html>
	<title>
	Redis Example
	</title>
	<body>
	<form action="/login" method="post">
	Username: <input type="text" name="username">
	Password: <input type="text" name="password">
	<input type="submit" value="Submit">
	</form>

	from datetime import datetime
	from sqlalchemy import Column, Integer, DateTime, ForeignKey
	from sqlalchemy.orm import relationship
	from sqlalchemy.ext.declarative import declared_attr
	from flask_security import current_user


	class AuditMixin(object):
	created_at = Column(DateTime, default=datetime.now)
	updated_at = Column(DateTime, default=datetime.now, onupdate=datetime.now)

	// Just before switching jobs:
	// Add one of these.
	// Preferably into the same commit where you do a large merge.
	//
	// This started as a tweet with a joke of "C++ pro-tip: #define private public",
	// and then it quickly escalated into more and more evil suggestions.
	// I've tried to capture interesting suggestions here.
	//
	// Contributors: @r2d2rigo, @joeldevahl, @msinilo, @_Humus_,
	// @YuriyODonnell, @rygorous, @cmuratori, @mike_acton, @grumpygiant,