mgreenly

Rules = {
  enter: [ 'created' ],
  exit: [ 'completed' ],
  uncancelable: %w[ completing completed ],
  tasks: [
      { 
        name: 'tag',
        desc: 'taggable',
        transitions: [
          { from: { state: 'tagging', :status: 'pending' }, to: { state: 'tagged' } },

mgreenly

require 'pp'

Rules = [
  {
    is: { state: 'created', status: 'pending', provider: 'aws' },
    in: 'taggable',
    to: { state: 'tagged' },
    as: { state: 'tagging' },
    on: 'housekeeper'
  },

mgreenly

require 'concurrent'

MAX_THREADS = 20

class Job
  def step
    sleep 3               # simulates performing the next task in the jobs workflow
  end
end

mgreenly

#
# The key thing to understand about this is that an `ensure` section is not guarnteed to run!
#
# If code executing is in the main thread of the process and a Interrupt, caused by a SIGINT or SIGTERM, occurs
# `ensure` blocks in that thread will not be executed.  This is because Interrupt is an asynchrnous event and
# Ruby has no way to return to the point in execution it left when the signal happened.
#
# But, because Interrupts are only processed in the main thread of a process, moving all the actual code of an
# application into a child thread fixes this problem.
#

mgreenly

# inherit from Enumerator
class Pager1 < Enumerator
  def initialize(url, page_size: 100, max_pages: Float::INFINITY, first_page: 0)
    @url = url
    super() do |receiver|
      page = first_page
      pages = []
      while page < (first_page + max_pages)
        get(page, page_size).each do |row|
          receiver.yield row

mgreenly

#!/bin/sh

tmux has-session -t notes > /dev/null 2>&1
if [ $? != 0 ]; then
  echo 'starting session: notes'
  tmux new-session -s notes -d
  tmux rename-window -t notes notes
  tmux send-keys -t notes "vim $DROPBOX_DIR/documents/notes.txt" C-M
fi

mgreenly

require 'logger'

# This logger will notice the log has been rotated and reopen it.
# The logrotate options must include 'nocreate'.
class RotatableLogger < Logger
  def add(*args)
    reopen if @logdev.filename && !File.exist?(@logdev.filename)
    super
  end
end

mgreenly

Process.setproctitle("foo-parent")

ppid = Process.pid
fork do
  exit if fork            # You can only setsid if you're in a child process so first we fork
  Process.setsid          # and exit the parent then setsid in the child.  Now that we have a
  exit if fork            # new session create a child process in it and exit the parent again.
  Dir.chdir("/")          # Finally, change directory to one that can't be deleted or moved.

  Process.setproctitle("foo-child")

mgreenly

require 'rack'
require 'rack/handler/puma'
require 'oj'

class Stats

  def initialize
    @stats = {}
    @lock = Mutex.new
  end

mgreenly

class Channel < SizedQueue
  def initialize
    super(1)
  end
end

channel = Channel.new

Thread.new(channel) do |ch|
  val = rand(3.0) + 1.0