Alexander Logvinov incubus

Polymorphic Associations reversed

It's pretty easy to do polymorphic associations in Rails: A Picture can belong to either a BlogPost or an Article. But what if you need the relationship the other way around? A Picture, a Text and a Video can belong to an Article, and that article can find all media by calling @article.media

This example shows how to create an ArticleElement join model that handles the polymorphic relationship. To add fields that are common to all polymorphic models, add fields to the join model.

ruby-1.9.3-p327 cumulative performance patch for rbenv

This installs a patched ruby 1.9.3-p327 with various performance improvements and a backported COW-friendly GC, all courtesy of funny-falcon.

Requirements

You will also need a C Compiler. If you're on Linux, you probably already have one or know how to install one. On OS X, you should install XCode, and brew install autoconf using homebrew.

Zero downtime deploys with unicorn + nginx + runit + rvm + chef

Below are the actual files we use in one of our latest production applications at Agora Games to achieve zero downtime deploys with unicorn. You've probably already read the GitHub blog post on Unicorn and would like to try zero downtime deploys for your application. I hope these files and notes help. I am happy to update these files or these notes if there are comments/questions. YMMV (of course).

Other application notes:

Our application uses MongoDB, so we don't have database migrations to worry about as with MySQL or postgresql. That does not mean that we won't have to worry about issues with the database with indexes being built in MongoDB or what have you.
We use capistrano for deployment.

Salient points for each file:

Devise / Warden Tagged logging

I wrote a middleware (actually two, but they do the same with different implementations) that logs information about signed in scopes in a Rails + Devise application. The solution works with multiple logins (like having a person logged both as an Admin and a User). I tested against Rails 4 and Devise HEAD, but it should work fine in any Rails 3 application.

This solution doesn't use the log_tags configuration option since it isn't very helpful when you need to retrieve information stored in cookies/session. That information isn't 'ready' when the Rails::Rack::Logger is executed, since it happens way down in the middleware chain.

Add one of the following implementations to your application load path and use the following configuration to add the middleware to your application stack:

# application.rb

	# unicorn_rails -c /data/github/current/config/unicorn.rb -E production -D

	rails_env = ENV['RAILS_ENV'] \|\| 'production'

	# 16 workers and 1 master
	worker_processes (rails_env == 'production' ? 16 : 4)

	# Load rails+github.git into the master before forking workers
	# for super-fast worker spawn times
	preload_app true

	require "time"
	require "date"

	class Date
	def to_time
	Time.local(year, month, day)
	end
	end

	class Time

	#!/usr/bin/env /usr/local/rvm/wrappers/ruby-1.9.2-p290@puppet/ruby
	## Used by M/Monit to send prowl alerts

	require 'rubygems'
	require 'optparse'


	# everyone's API keys
	contact_info = {
	"grant"=>{"key"=>"my_api_key"}

	# Nginx+Unicorn best-practices congifuration guide. Heartbleed fixed.
	# We use latest stable nginx with fresh openssl, zlib and pcre dependencies.
	# Some extra handy modules to use: --with-http_stub_status_module --with-http_gzip_static_module
	#
	# Deployment structure
	#
	# SERVER:
	# /etc/init.d/nginx (1. nginx)
	# /home/app/public_html/app_production/current (Capistrano directory)
	#

	require 'faraday'
	require 'zlib'

	module FaradayMiddleware
	class Gzip < Faraday::Response::Middleware

	def on_complete(env)
	encoding = env[:response_headers]['content-encoding'].to_s.downcase
	case encoding
	when 'gzip'

	upstream some_app_server {
	server 127.0.0.1:9393;
	}

	server {
	listen 80;

	server_name my-upload-endpoint.com ;