ololo-psh

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

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# This task should be run inside an environment that is already configured to connect to the redis
# instance that we're transfering AWAY FROM.
#
# The task should be handed the URL of the redis instance that we're MOVING TO.
#
# To run it and pass in the destination Redis you'd do something like this:
# rake sidekiq:transfer[redis://...]
#
# As jobs are added to the destination Redis, they're deleted from the source Redis. This
# allows the task to be restarted cleanly if it fails in the middle due to a network error

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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

ololo-psh

PSQL

Magic words:

psql -U postgres

If run with -E flag, it will describe the underlaying queries of the \ commands (cool for learning!).

Most \d commands support additional param of __schema__.name__ and accept wildcards like *.*

ololo-psh

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

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ActiveRecord cheat sheet / EXAMPLES

INSTALL 
=======  
$ gem install activerecord
in GEMFILE: gem ‘activerecord’

REQUIRE 
=======  
require ‘active_record’

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Steps to install and run PostgreSQL 9.2 using Homebrew (Mac OS X)
(if you aren't using version 9.1.5, change line 6 with the correct version)

1. launchctl unload -w ~/Library/LaunchAgents/homebrew.mxcl.postgresql.plist
2. mv /usr/local/var/postgres /usr/local/var/postgres91
3. brew update
4. brew upgrade postgresql
5. initdb /usr/local/var/postgres -E utf8
6. pg_upgrade -b /usr/local/Cellar/postgresql/9.1.5/bin -B /usr/local/Cellar/postgresql/9.2.0/bin -d /usr/local/var/postgres91 -D /usr/local/var/postgres
7. cp /usr/local/Cellar/postgresql/9.2.0/homebrew.mxcl.postgresql.plist ~/Library/LaunchAgents/

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# lib/custom_logger.rb
class CustomLogger < Logger
  def format_message(severity, timestamp, progname, msg)
    "#{timestamp.to_formatted_s(:db)} #{severity} #{msg}\n"
  end
end

logfile = File.open("#{Rails.root}/log/custom.log", 'a')  # create log file
logfile.sync = true  # automatically flushes data to file
CUSTOM_LOGGER = CustomLogger.new(logfile)  # constant accessible anywhere

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# 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

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"]