Simeon Simeonov ssimeonov

Writing Bug-Free Chef Recipes

Chef has unique abstraction and processing models. Until you understand them, it is easy to write buggy recipes.

The most important thing to understand is the following: a Chef recipe is not a collection of scripts.

Chef Processing Model

	<html>

	<head>
	<script src="//ajax.googleapis.com/ajax/libs/jquery/1/jquery.min.js"></script>
	<script src="http://ajax.googleapis.com/ajax/libs/jquery/1/jquery.js"></script>
	</head>

	<body>
	<div id="main_wrapper">
	<div id="main_wrapper_top"></div>

	function replaceDoc(html) {
	var newDoc = document.open("text/html", "replace");
	newDoc.write(html);
	newDoc.close();
	}

	require 'open-uri'
	require 'json'

	API = 'https://api.github.com/users/swoop-inc/repos'

	open(API) do \|io\|
	puts JSON.parse(io.read).
	reject { \|repo\| repo['fork'] }.
	map { \|repo\| repo['full_name'] }.
	to_json

	class ChoiceSequence
	MAX_CHOICES = 26
	MAX_SEQUENCE_LENGTH = 25

	FACTORIAL = (1..MAX_SEQUENCE_LENGTH).reduce([1]) do \|memo, n\|
	memo << memo.last * n
	end.freeze

	def self.position(seq)
	length = seq.length

	# ADD LOCAL CONFIGURATION HERE

	[user]
	name = Simeon Simeonov
	email = sim@fastignite.com

	[core]
	editor = mate -w
	excludesfile = /Users/sim/.gitignore_global

	2014-01-31T08:25:13.684816+00:00 app[analytics.1]: ** [NewRelic][01/31/14 08:25:13 +0000 213b2cc6-fb96-4c1a-b031-9edexxxxxxxx (2)] WARN : Error during check_for_and_handle_agent_commands, will retry later:
	2014-01-31T08:25:13.684816+00:00 app[analytics.1]: ** [NewRelic][01/31/14 08:25:13 +0000 213b2cc6-fb96-4c1a-b031-9edexxxxxxxx (2)] WARN : NewRelic::Agent::ServerConnectionException: Service unavailable (503): Service Unavailable

	def publish(data)
	configure
	conn = Bunny.new(connection_uri).start
	channel = conn.create_channel
	queue = channel.queue(queue_name, durable: true)
	exchange = channel.direct(exchange_name, durable: true)
	log_data(data)
	exchange.publish(data, :routing_key => queue.name)
	queue_status(queue.status)
	rescue Exception => e

	task :cache_size => :environment do
	require 'objspace'

	def calc_overhead(run, count)
	cache = ActiveSupport::Cache.lookup_store :memory_store, size: 128.gigabytes
	# keep all key/value pairs unique
	cache.instance_variable_get(:'@data').compare_by_identity

	GC.start
	before = ObjectSpace.count_objects_size({})[:TOTAL]

	# Syntax sugar
	class ArrayValidator < EnumValidator
	end