Gerhard Lazu gerhard

Coding Rails with Homebrew

Right now, this assumes you are using Snow Leopard.

Install Homebrew

Homebrew is MacPorts (or APT) without the suck. http://github.com/mxcl/homebrew

Instrument Anything in Rails 3

With Rails 3.0 released a few weeks ago I've migrated a few apps and I'm constantly finding useful new improvements. One such improvement is the ability to log anything in the same way that Rails internally logs ActiveRecord and ActionView. By default Rails 3 logs look slightly spiffier than those produced by Rails 2.3: (notice the second line has been cleaned up)

Started GET "/" for 127.0.0.1 at Mon Sep 06 01:07:11 -0400 2010
  Processing by HomeController#index as HTML
  User Load (0.2ms)  SELECT `users`.* FROM `users` WHERE (`users`.`id` = 3) LIMIT 1
  CACHE (0.0ms)  SELECT `users`.* FROM `users` WHERE (`users`.`id` = 3) LIMIT 1

Rendered layouts/_nav.html.erb (363.4ms)

Fibur

Fibur is a library that allows concurrency during Ruby I/O operations without needing to make use of callback systems. Traditionally in Ruby, to achieve concurrency during blocking I/O operations, programmers would make use of Fibers and callbacks. Fibur eliminates the need for wrapping your I/O calls with Fibers and a callback. It allows you to write your blocking I/O calls the way you normally would, and still have concurrent execution during those I/O calls.

Example

Say you have a method that fetches data from a network resource:

	# Author: Pieter Noordhuis
	# Description: Simple demo to showcase Redis PubSub with EventMachine
	#
	# Requirements:
	# - rubygems: eventmachine, thin, cramp, sinatra, yajl-ruby
	# - a browser with WebSocket support
	#
	# Usage:
	# ruby redis_pubsub_demo.rb
	#

	#!/bin/sh
	#
	# init.d script for single or multiple unicorn installations. Expects at least one .conf
	# file in /etc/unicorn
	#
	# Modified by jay@gooby.org http://github.com/jaygooby
	# based on http://gist.github.com/308216 by http://github.com/mguterl
	#
	## A sample /etc/unicorn/my_app.conf
	##

	Prototype mysql_grant provider for Chef
	---------------------------------------

	Drop the two files into your mysql cookbook, and experiment with the following examples:

	mysql_grant "kenneth" do
	action :grant
	username "root" # <- User with admin privs
	password node[:mysql][:server_root_password]
	# Actual grant details

	require "fiber"
	require "rack/fiber_pool"
	require "sinatra/base"

	require "redis"
	require "redis/connection/synchrony"

	class App < Sinatra::Base
	use Rack::FiberPool

	require 'goliath'
	require 'em-synchrony/em-http'

	class TwilioResponse < Goliath::API
	use Goliath::Rack::Params
	use Goliath::Rack::JSONP

	HEADERS = { authorization: ENV.values_at("TWILIO_SID","TWILIO_AUTH_TOKEN") }
	BASE_URL = "https://api.twilio.com/2010-04-01/Accounts/#{ENV['TWILIO_SID']}/AvailablePhoneNumbers/US"

	# Here a few bash one-liners that helped me analyze / fight a weak DOS attack against debuggable.com. Mostly for future reference.
	# The attacker was opening lots of tcp connections without sending data, I believe it's called a SYN flood, see: http://tools.ietf.org/html/rfc4987#section-3.2

	# Step 0: Check what is going on at port 80
	$ netstat -tan \| grep ':80 ' \| awk '{print $6}' \| sort \| uniq -c

	# Step 1: Increase the number of available fds
	$ ulimit -n 32000

	# Step 2: Restart your webserver, for me: