Dmitry Polushkin dmitry

My largest Sidekiq application had a memory leak and I was able to find and fix it in just few hours spent on analyzing Ruby's heap. In this post I'll show my profiling setup.

As you might know Ruby 2.1 introduced a few great changes to ObjectSpace, so now it's much easier to find a line of code that is allocating too many objects. Here is great post explaining how it's working.

I was too lazy to set up some seeding and run it locally, so I checked that test suite passes when profiling is enabled and pushed debugging to production. Production environment also suited me better since my jobs data can't be fully random generated.

So, in order to profile your worker, add this to your Sidekiq configuration:

if ENV["PROFILE"]

React

Flux

React (Virtual) DOM Terminology

In React's terminology, there are five core types that are important to distinguish:

ReactElement / ReactElement Factory
ReactNode
ReactComponent / ReactComponent Class

React Elements

Thoughts on a Meteor ORM

While we're approaching the 1.0 release of Meteor, the need and interest in additional databases support (other than MongoDB) has risen consequently. Thus, SQL support is the second most requested feature on the official meteor roadmap (after server-side rendering) and there have been various demands on the forums about supporting Redis (also on the roadmap), RethinkDB, LevelDB, Neo4J, ElasticSearch, Mysql/MariaDB, PosgreSQL, SQLite and some other. More importantly the Meteor community has started to work on atmosphere packages that bring support for these databases and it appeared to be a very difficult task – most projects were abandoned.

The problem

What makes the integration of a new database a lot harder in Meteor than in most other web frameworks (including “full stack” JavaScript frameworks like Derby or Sails) lies in the third [principle of Meteor](http://docs.meteor.com/

Why test?

Design API;
Make sure code is working as it should;
Regression check.

Look how it's easy - all about time:

plan (before);
implement (current);

	Architecture description
	-

	Aggregator
	Orchestrates the overall process from fetching to updating the db,
	scheduling and managing aggregator jobs and their stages for different modules

	does:
	fetch :all \| latest - accepts a block with strategy to determine latest
	jobs :all \| :current - AggreagationJob - status, stop, pause, resume

	// Mixin that allows to specify arbitrary CSS properties with
	// unitless numbers. The output has rem unit with pixel fallback.
	// Shorthand assignments are supported too!
	$base_line: 10;

	@mixin rem($property, $values, $important:"")
	{
	// Placeholder variables
	$shorthand_px: "";
	$shorthand_rem: "";

	require 'nokogiri'
	require 'open-uri'

	# Get a Nokogiri::HTML:Document for the page we're interested in...

	doc = Nokogiri::HTML(open('http://www.google.com/search?q=tenderlove'))

	# Do funky things with it using Nokogiri::XML::Node methods...

	####

	# app/models/address.rb

	class Address < ActiveRecord::Base
	belongs_to :addressable, polymorphic: true
	end

	# config/application.rb
	config.exceptions_app = ->(env) { ErrorsController.action(:show).call(env) }