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Unicorn memory usage improvement with Ruby 2.0.0

Here's a preliminary experiment to see how much memory is saved with the new copy-on-write friendly (bitmap marking) GC.

Calculated by memstats.rb https://gist.github.com/kenn/5105061 on Debian x86_64.

Master process:

# ./memstats.rb 20547

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class User < ActiveRecord::Base
  # ... lots of persistence stuff
end

class GitHubUserProvisioner < SimpleDelegator
  def provision_with!(user_info, extra_user_hash)
    self.github_login = extra_user_hash['login']
    self.name = user_info['name']
    self.email = user_info['email']
    self.github_url = user_info['urls']['GitHub']

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def stuff
  yield action: 'Boom', schedule: '7PM', color: :red, debug: true
end

# When a hash is yielded to a block, we can used named arguments to
# capture the keys we want, and an anonymous splat to ignore
# everything else
stuff { |action:, schedule:, **| p "Doing #{action} at #{schedule}" }

#

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Security Advisories / Bulletins linked to Log4Shell (CVE-2021-44228)

Errors, typos, something to say ?

• If you want to add a link, comment or send it to me
• Feel free to report any mistake directly below in the comment or in DM on Twitter @SwitHak

Other great ressources

• Royce Williams list is different, listed by vendors responses:
• https://www.techsolvency.com/story-so-far/cve-2021-44228-log4j-log4shell/
• TBD

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bogn83

# prune branches deleted in origin
git remote prune origin

# prune tags
# http://stackoverflow.com/questions/1841341/remove-local-tags-that-are-no-longer-on-the-remote-repository
git fetch --prune <remote> '+refs/tags/*:refs/tags/*'

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# retrieves commit relative date and message
humanify() {
  while read hash; do
    # echo to trim the new line
    echo $( git log -n 1 ..$hash --format='%ci : %h : %s%n%b' )
  done
}

# show the commits!
git fsck --unreachable | grep -oP '(?<=commit )\w+' | humanify | sort

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Make sessions queryable by user with ActiveRecord Session Store and Devise

1. Install the ActiveRecord Session Store gem and read the documentation for how to use it and create your sessions table.

2. Create a migration to add user_id to the sessions table.

class AddUserIdToSessions < ActiveRecord::Migration
  disable_ddl_transaction!

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# Flags Ruby

# Sentinel to check that the rbenv-vars plugin is in use.
RBENV_VARS_ENABLED=1

# Ruby 2.1 GC reading:
# http://tmm1.net/ruby21-rgengc/
# http://thorstenball.com/blog/2014/03/12/watching-understanding-ruby-2.1-garbage-collector/
# http://samsaffron.com/archive/2013/11/22/demystifying-the-ruby-gc

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tmux shortcuts & cheatsheet

start new with session name:

tmux new -s myname

attach to named:

tmux a -t myname