Decadent Gingerbread ololo-psh

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"]

PSQL

Magic words:

psql -U postgres

Some interesting flags (to see all, use -h or --help depending on your psql version):

-E: will describe the underlaying queries of the \ commands (cool for learning!)
-l: psql will list all databases and then exit (useful if the user you connect with doesn't has a default database, like at AWS RDS)

Moved to git repository: https://github.com/denji/jetbrains-cleanup-backup

Quick `uninstall` JetBrains settings:

curl -sL https://gist.github.com/denji/9731967/raw/jetbrains-uninstall.sh | bash -s

Quick `backup` JetBrains settings:

curl -sL https://gist.github.com/denji/9731967/raw/jetbrains-backup.sh | bash -s

How to install PhantomJS on Ubuntu

Version: 1.9.8

Platform: x86_64

First, install or update to the latest system software.

sudo apt-get update
sudo apt-get install build-essential chrpath libssl-dev libxft-dev

Update and upgrade the system

sudo apt-get update && sudo apt-get upgrade && sudo apt-get dist-upgrade && sudo apt-get autoremove
sudo reboot

	docker build -t friendlyname . # Create image using this directory's Dockerfile
	docker run -p 4000:80 friendlyname # Run "friendlyname" mapping port 4000 to 80
	docker run -d -p 4000:80 friendlyname # Same thing, but in detached mode
	docker exec -it [container-id] bash # Enter a running container
	docker ps # See a list of all running containers
	docker stop <hash> # Gracefully stop the specified container
	docker ps -a # See a list of all containers, even the ones not running
	docker kill <hash> # Force shutdown of the specified container
	docker rm <hash> # Remove the specified container from this machine
	docker rm $(docker ps -a -q) # Remove all containers from this machine

	require "net/http"

	def start_server
	# Remove the X to enable the parameters for tuning.
	# These are the default values as of Ruby 2.2.0.
	@child = spawn(<<-EOC.split.join(" "))
	XRUBY_GC_HEAP_FREE_SLOTS=4096
	XRUBY_GC_HEAP_INIT_SLOTS=10000
	XRUBY_GC_HEAP_GROWTH_FACTOR=1.8
	XRUBY_GC_HEAP_GROWTH_MAX_SLOTS=0

	# read more at https://terrty.net/2014/ssl-tls-in-nginx/
	# latest version on https://gist.github.com/paskal/628882bee1948ef126dd/126e4d1daeb5244aacbbd847c5247c2e293f6adf
	# security test score: https://www.ssllabs.com/ssltest/analyze.html?d=terrty.net
	# your nginx version might not have all directives included, test this configuration before using in production against your nginx:
	# $ nginx -c /etc/nginx/nginx.conf -t

	server {
	# public key, contains your public key and class 1 certificate, to create:
	# (example for startssl)
	# $ (cat example.com.pem & wget -O - https://www.startssl.com/certs/class1/sha2/pem/sub.class1.server.sha2.ca.pem) \| tee -a /etc/nginx/ssl/domain.pem > /dev/null

	# less to scss based on http://stackoverflow.com/a/19167099/2363935
	namespace :convert do

	task :less_to_scss do

	source_glob = "assets/less/*.less"
	dest_dir = "converted"

	rm_r dest_dir rescue nil
	mkdir_p(dest_dir)

	# this monit config goes in /etc/monit/conf.d

	check process puma_master
	with pidfile /data/myapp/current/tmp/puma.pid
	start program = "/etc/monit/scripts/puma start"
	stop program = "/etc/monit/scripts/puma stop"
	group myapp

	check process puma_worker_0
	with pidfile /data/myapp/current/tmp/puma_worker_0.pid