1. Telephony Applications
with
MongoDB,
OpenShift,
& Twilio
Mark Atwood
Developer Evangelist for Red Hat
OpenShift
me@mark.atwood.name
Twitter @fallenpegasus

2. What is OpenShift?
 Red Hat cloud Platform as a Service
 Free as in beer, Free as in speech
 Languages: Python, Java, Ruby, Node, PHP, & DIY
 Storage: Filesystem, MySQL, Postgres, MongoDB
 No lock-in, no proprietary APIs
 Sign up at http://openshift.redhat.com
 Promo code SEATTLE
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3. What is Twilio?
 A cloudy API for telephony
 REST interface to the PSTN: Voice & SMS
 Pay by the drink
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4. How Twilio voice works
 Someone calls the number
 Twilio answers the phone
 Twilio does HTTP REST to our app
 Our app replies with some "TwiML"
 Twilio does what the app told it to
 Twilio or the caller hangs up the phone
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5. How Twilio SMS works
 Someone texts to the number
 Twilio receives the text & all metadata
 Twilio does HTTP REST to our app
 Our app replies with some "TwiML"
 Twilio does what the app told it to
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6. What is MongoDB?
 If you have to ask that, you shouldn't be here!
 Easy to use JSONic Document Store
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7. What is Python & What is Bottle?
 My favorite programming language
 My favorite web framework
 Supported by OpenShift
 Drivers for MongoDB & for Twilio
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8. A simple app: SMS Group
 SMS group chat
 http://github.com/fallenpegasus/openshift-smsgroup
 +1-XXX-XXX-XXXX
 SMS .join to join
 SMS .leave to leave
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9. Glue it all together
 Get an OpenShift account
 Get a Twilio account
 Spin up "smsgroup" app in OpenShift
 Attach it to your Twilio account
 Play!
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10. Agenda for Demonstration
 Look at the app at twilio.com
 Look at the app at openshift.com
 SSH into the app
 Port forward from local to remote MongoDB
 Run local MongoDB clients
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11. 11

12. Some useful software design guidelines
 Let the language, the libraries, & remote services do the
boring work
 Don't keep state in the app, use a data layer
 Use queuing to smooth load
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13. Don't keep state in the app
 Keep it in the data layer instead
 OpenShift might restart or scale the instance at any time
 Don't waste time keeping complex data in the instance
 Don't try to write your own database server
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14. Don't keep state in the app
 Keep it in the data layer instead
 OpenShift might restart or scale the instance at any time
 Don't waste time keeping complex data in the instance
 Don't try to write your own database server
 MongoDB is an excellent solution
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15. Use queuing to smooth the load
 Don't depend on "their" capacity
 Getting local storage quickly is easier than provisioning
more CPU, IO ops, or network bandwidth
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16. Use queuing to smooth the load
 Don't depend on "their" capacity
 Getting local storage quickly is easier than provisioning
more CPU, IO ops, or network bandwidth
 And it's cheaper
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17. Some Queue options
 roll your own
 SQS
 AQMP
 RabbitMQ
 etc
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18. Queue options
 roll your own
 SQS
 AQMP
 RabbitMQ
 etc
 MongoDB "find_and_modify"
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19. def worker:
while True:
time.sleep(1)
while True:
msg = mongo_db.sendq.find_and_modify(remove = True)
if (msg == None): break
message = twilio_client.sms.message.create(
to = msg['To'],
from_ = twilio_fromnum,
body = msg['Body'])
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20. Conclusion
 Telephony apps are easy and fun
 You can build your own
 Using OpenShift, Twilio, and MongoDB
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21. Questions?
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