How Test Driven Development started the Robot Apocalypse; Lessons learned using Twilio for Telephony

Lessons Learned Using
and Testing with Twilio
Tips, Tricks, and Best Practices

Sunday, December 16, 12

How Test Driven
Design started the
Robot Apocalypse!
... And how it's not my fault!


Customer Call System


Wanted New Efﬁciencies
1. Connecting customers to the same agent;
developing a personal relationship.
2. Automatically popping up the customer record
on the agent's browser.
3. Collect call metrics and tie into other
datapoints.


Current Provider...
1. Offered little to no real-time integration.
2. Was unable or unwilling to customize solution.
3. Was expensive.


Twilio...
1. A REST-ful API to make and manipulate calls
and their associated data.
2. Makes real-time callbacks over HTTP to your
application about incoming and ongoing calls.
3. Inexpensive: $1 per number, $0.01 per call leg


[censored client]


Call Flows
1. A user can click-to-call a target; the user's
phone is called ﬁrst and is then connected to
the target.
2. A user can enter any number and call it; the
user's phone is called ﬁrst and is then
connected to the number.
3. If a target calls the mainline, they are
immediately connected to a user.
4. Unknown callers to the mainline are placed on
a hold queue; any user can handle them.


Excellent Documentation
https://twilio.com/docs


Productizing Twilio
http://kalzumeus.com/2011/12/19/productizing-twilio-applications/


Treat TwiML as Your
View
We use Builder to generate XML


TWiML Builder View
xml.instruct!
xml.Response do
xml.Say 'Hello. Are you'
xml.Play 'https://s3.amazonaws.com/CarbonFive/placeholder.wav'
xml.Say 'If not, please hold.'
xml.Play 'https://s3.amazonaws.com/CarbonFive/sign_off.wav'
xml.Enqueue(action: goodbye_twilio_call_path(@call),
waitUrl: hold_twilio_call_path(@call)) do
xml.text! 'hold'
end
end


Port-Forward Callbacks
To Development
Set it up yourself or use:
localtunnel http://localtunnel.com
forward http://forwardhq.com


Model Calls AND
Conversations
We made heavy use of state_machine gem
https://github.com/pluginaweek/state_machine


Where's the
Robopocalypse?


Testing


Deprecated Sandbox


Test Account
Like payment providers, it allows you to make
dummy calls, with speciﬁc phone numbers
resulting in speciﬁc responses.


Record responses with
VCR
Speeds up test suite.
https://github.com/myronmarston/vcr


Conversations make for
Messy State Machines


On top of all that, we
were still ﬁguring it out!


Changes would blow
away functionality!


Testing became
Manual Labor
Our poor PM constantly clicking through
scenarios.


Phonio
Made use of Twilio JS Client to provide multiple
numbers backed by another Twilio account.


How could we automate
this?
As part of the build and continuous integration.


I didn't know


Gaming Bots
Scripts that would act as other players to in
networked games.


Capybara
RSpec and Cucumber features use it to script a
user going through your application.


Remote Host
Capybara.run_server = false
Capybara.app_host = 'http://staging.cyberdyne.com'

Alternatively
require 'capybara/cucumber'
require 'capybara/spec/test_app'

Capybara.app = TestApp
Capybara.app_host = 'http://staging.cyberdyne.com'


Supports Multi-"Users"
using_session :ahnold do
visit '/signin'
click 'Terminate', within: '#sarah_connor'
end

using_session :robert do
visit '/sightings/new'
check 'have_you_seen_this_boy'
click 'Submit'
end


How to do the same for
phones?


We're are NOT testing
Twilio.


We are testing WITH
Twilio.
An important distinction!


The Pieces to a Solution
were lying around.


What does it look like?
Twilio Account
Capybara The App
Browser of the App
Rspec/
Cucumber


Twilio Account
Capybara The App
Browser of the App
Rspec/
Cucumber

Twilio Account
of the Bots


Twilio Account
Capybara The App
Browser of the App
Rspec/
Cucumber

Sinatra

Twilio Account
of the Bots


Twilio Account
Capybara The App
Browser of the App
Rspec/
Cucumber

Sinatra

Twilio Account
of the Bots
Calls


Twilio Account
Capybara The App
Browser of the App
Rspec/
Cucumber

Sinatra

Twilio Account
of the Bots
Bots Calls


Twilio Account
Capybara The App
Browser of the App
Rspec/
Cucumber

Sinatra

Twilio Account
of the Bots
Bots Calls

Twilio Client


WOPR
http://github.com/ZestFinance/wopr
http://github.com/carbonﬁve/wopr


A @wopr of a Feature
@javascript @wopr
Feature: Outbound Call
A user can enter phone number so that they can call it

Scenario: Simple Session
Given a user is logged in
And the user enters a phone number
And the user clicks the Call button
Then the user's phone is called
And the phone number is called
And they are speaking to each other


Setup in Cucumber
require 'wopr/cucumber'

require File.join(File.dirname(__FILE__), '..', '..', 'staging')

Wopr.configure do |config|
config.twilio_server_port = 4000
config.twilio_callback_host = 'http://rudyjahchan.fwd.wf'
config.twilio_account_sid = TWILIO_ACCOUNT_SID
config.twilio_auth_token = TWILIO_AUTH_TOKEN
end

require File.join(File.dirname(__FILE__), '..', '..', 'bots')

Wopr::TwilioService.new.update_callbacks([
Wopr::Bot[:ahnold].phone_number,
Wopr::Bot[:kyle].phone_number])

Wopr::TwilioCallbackServer.boot


Creat identiﬁed Bots
Wopr::Bot.create(:ahnold,
email: 'rudy+ahnold@carbonfive.com',
password: 'n07@r3@1p@$$w0rd',
phone_number: '5558675309')

Wopr::Bot.create(:kyle,

Wopr::Bot.create(:sarah,


The Goal: Simpler Code
Then /^the user's phone is called$/ do
bot(:ahnold).should be_on_a_call
end

Then /^the user's phone is not called$/ do
bot(:ahnold).should_not be_on_a_call
end

Then /^the phone number is called$/ do
bot(:kyle).should be_on_a_call
end

Then /^they are speaking to each other$/ do
bot(:kyle).should be_on_a_call_with(bot(:ahnold))
end

Given /^an unknown caller dials the main line$/ do
bot(:kyle).make_a_call_to(CYBERDYNE_STAGING_PHONE_NUMBER)
end


How does it work?


Stole a LOT from
Capybara
Particularly threading code not to block running
specs.


Sinatra App
module Wopr
class TwilioCallbackServer < Sinatra::Base
VERIFICATION_PHRASE = 'SHALL WE PLAY A GAME?'

set :views,
File.join(File.dirname(__FILE__), 'templates')

get '/__identify__' do
[200, {}, VERIFICATION_PHRASE]
end

post '/calls' do
# ...
end

# ...

end
end


Mount on Rack
def run_server(port)
require 'rack/handler/thin'
Thin::Logging.silent = true
Rack::Handler::Thin.run(self,
Port: port)
rescue LoadError
require 'rack/handler/webrick'
Rack::Handler::WEBrick.run(self,
Port: port,
AccessLog: [],
Logger: WEBrick::Log::new(nil, 0))
end


Launch in a thread
def boot(port=Wopr.twilio_server_port)
@port = port
unless responsive?
@server_thread = Thread.new { run_server(@port) }
end

Timeout.timeout(60) { @server_thread.join(0.1) until responsive? }
end

def responsive?
return false if @server_thread && @server_thread.join(0)

res = Net::HTTP.start('127.0.0.1', @port) do |http|
http.get('/__identify__')
end

if res.is_a?(Net::HTTPSuccess) or res.is_a?(Net::HTTPRedirection)
return res.body == VERIFICATION_PHRASE
end
rescue Errno::ECONNREFUSED, Errno::EBADF
return false
end


Server manages Calls
post '/calls' do
if(call = Call.find_by_sid(params[:CallSid]))
call.update params
else
Call.create(params)
end

builder :default
end


<Say /> Keep-alive
xml.instruct!
xml.Response do
xml.Say(loop: 0) do
xml.text! <<GIBBERISH
Yorn desh born, der ritt de gitt der gue,
Orn desh, dee born desh, de umn
bork! bork! bork!
GIBBERISH
end
end


Bots can examine Calls
module Wopr
class Bot

# ...

def current_call
Call.find_all_by_number(phone_number).select{|call|
call.status != 'completed'}.last
end

def on_a_call?
wait_until do
current_call
end
end

# ...

end
end


Handle Asynchronicity
def eventually(seconds=Wopr.default_wait_time)
start_time = Time.now
begin
yield
rescue => e
raise e if (Time.now - start_time) >= seconds
sleep 1
retry
end
end

def wait_until(seconds=Wopr.default_wait_time)
eventually(seconds) do
result = yield
return result if result
raise ConditionNotMetError
end
rescue ConditionNotMetError
return false
end


Bot makes calls w/ Call
module Wopr
class Bot

# ...

def make_a_call_to(phone_number)
Call.make(from: self.phone_number, to: phone_number)
end

# ...
end
end

module Wopr
class Call
class << self
def make(options)
TwilioService.new.make(options)
end

# ...


TwilioClientService
require 'twilio-ruby'

module Wopr
class TwilioService
def initialize
@twilio_client = Twilio::REST::Client.new(
Wopr.twilio_account_sid,
Wopr.twilio_auth_token
)
end

def make(options)
calls.create(options.merge(
url: "#{Wopr.twilio_callback_host}/calls"
))
end

def hangup(sid)
call(sid).hangup
end
# ...


Do we KNOW they're
TALKING to each other?
It's possible the system made two phone calls, but
they’re not with each other.


A Solution: Play and
Detect Dial Tones!
One bot starts to <Gather> digits, the other
<Plays> them, and we conﬁrm they receive it.


Call Gather & Play
module Wopr
class Call

# ...

def play(digits)
TwilioService.new.play sid, digits
end

def gather
TwilioService.new.gather sid
end

# ...

end
end


Redirect Calls to TWiML
module Wopr
class TwilioService

# ...

def play(sid, digits)
call(sid).redirect_to(
"#{Wopr.twilio_callback_host}/calls/#{sid}/play?digits=#{digits}"
)
end

def gather(sid)
call(sid).redirect_to(
"#{Wopr.twilio_callback_host}/calls/#{sid}/gather"
)
end

# ...

end
end


Prepare to <Gather />
module Wopr

# ...

post '/calls/:sid/gather' do
builder :gather, locals: { sid: params[:sid] }
end

# ...
end
end

gather.builder
xml.instruct!
xml.Response do
xml.Gather(
timeout: "60",
action: "#{Wopr.twilio_callback_host}/calls/#{sid}/gathered",
numDigits: "4")
end


<Play digits="..." />
module Wopr

# ...

post '/calls/:sid/play' do
builder :play, locals: { sid: params[:sid], digits:
params[:digits] }
end

# ...
end
end

play.builder
xml.instruct!
xml.Response do
xml.Play(digits: digits)
xml.Pause(length: 10)
end


Gathered Digits Posted
module Wopr

# ...

post '/calls/:sid/gathered' do
if(call = Call.find_by_sid(params[:sid]))
call.gathered params[:Digits]
end

builder :default
end

# ...

end
end


Again Asynchronous!
module Wopr
class Bot

# ...

def on_a_call_with?(another_bot)
current_call.gather
sleep 1
another_bot.current_call.play '6661'
wait_until do
current_call.gathered_digits.last == '6661'
end
end

# ...

end
end


Dial-Tone not a Perfect
Solution.
What if tones are used to trigger actions? And
how do we conﬁrm audio FILE playback?


<Record> and SOX
Retrieve the recording, digest with SOX audio
library.


More Capybara Tie-ins?
Given /^a user is logged in$/ do
bot(:ahnold).log_in
end

Given /^the user enters a phone number$/ do
bot(:ahnold).within('div#call') do
fill_in 'number', with: bot(:kyle).phone_number
end
end


How far can we take it?


[pic]


Sample Use of wopr
http://github.com/carbonﬁve/cyberdyne-systems


Questions?
rudy@carbonﬁve.com
@rudy on Twitter


Hasta la vista, baby!


How Test Driven Development started the Robot Apocalypse; Lessons learned using Twilio for Telephony

Recommended

Recommended

More Related Content

Similar to How Test Driven Development started the Robot Apocalypse; Lessons learned using Twilio for Telephony

Similar to How Test Driven Development started the Robot Apocalypse; Lessons learned using Twilio for Telephony (20)

Recently uploaded

Recently uploaded (20)

How Test Driven Development started the Robot Apocalypse; Lessons learned using Twilio for Telephony