tansengming

curl --silent https://raw.githubusercontent.com/cmusphinx/cmudict/master/cmudict.dict |
egrep '[a-z]+\s+[^AEIOU]*[AEIOU]+[^AEIOU]+[AEIOU]+[^AEIOU]*$' |
perl -pe 's/([a-z]+).*/\1/' |
comm --nocheck-order -12 - /usr/share/dict/words |
shuf -n 2

tansengming

require 'irb'
require 'pathname'
require 'json'
require 'rake/clean'
require 'time'

class Tweet
  attr_reader :tweet_id, :created_at

  def initialize(row)

tansengming

commnunity.users.each do |recipient|
  sms_credits = community.sms_credits

  if sms_credits > 0
    # this chucks the job into a queue and returns immediately!
    SmsSenderJob.perform_later recipient, 'Everything is fine.'

    # take off a credit
    community.sms_credits = sms_credits - 1
    community.save

tansengming

# Job 1
sms_credits = community.sms_credits # start with 100 credits
# Switch! -------------------------------------------------------------------
                      # Job 2
                      sms_credits = community.sms_credits # still 100 credits!!
                      if sms_credits > 0
                        send_sms recipient, message

                        # take off a credit
                        community.sms_credits = sms_credits - 1

tansengming

# Job 1
sms_credits = community.sms_credits # start with 100 credits 
if sms_credits > 0
  send_sms recipient, message

  # take off a credit
  community.sms_credits = sms_credits - 1
  community.save # 99 credits
end

tansengming

class SmsSenderJob < ApplicationJob
  def perform(recipient, community, message)
    sms_credits = community.sms_credits

    if sms_credits > 0
      send_sms recipient, message # this still takes a while.

      # take off a credit
      community.sms_credits = sms_credits - 1
      community.save

tansengming

commnunity.users.each do |recipient|
  # this chucks the job into a queue and returns immediately!
  # it no longer takes a while to finish.
  SmsSenderJob.perform_later recipient, community, 'Everything is fine.'
end

# Here's where you define the job that gets run by the workers
class SmsSenderJob < ApplicationJob
  def perform(recipient, community, message)
    sms_credits = community.sms_credits

tansengming

Thread Safely (Draft 3)

Introduction

I have mistakenly believed that I did not have to worry about thread safety in Regular Ruby because of the Global Interpreter Lock. Unfortunately the GIL is there to protect the Interpreter, not to save me from my dumb ass code. This post is based on a true story.

The Setup

Let’s say I needed to send an SMS to everyone in a community. Let’s say every community had to pay for sms credits and I had to check for credits before sending their SMS. I could start with this,

tansengming

class SmsSenderJob < ApplicationJob
  def perform(recipient, message)
    send_sms(recipient, message)
  end

  def send_sms(recipient, message)
    # ...
  end
end

tansengming

community.users.each do |recipient|
  sms_credits = community.sms_credits

  if sms_credits > 0
    send_sms recipient, 'Everything is fine.'

    # take off a credit
    community.sms_credits = sms_credits - 1
    community.save
  end