1. Jonathan H. Wage
OpenSky
Tuesday, May 8, 12

2. Who am I?
• My name is Jonathan H. Wage
• Director of Technology at OpenSky.com
• Started OpenSky Nashville office
• Open Source Software evangelist
• Long time Symfony and Doctrine core
contributor
OpenSky
Tuesday, May 8, 12

3. What is OpenSky?
• Social discovery shopping website
• Select your own team of people
• Experts, influencers and tastemakers from the
fields of:
–fashion
–food
–healthy living
–home
–kids
• They'll select the best products out there—
just for you.
OpenSky
Tuesday, May 8, 12

4. 1 Year of Business
• 1 year of business on April 1st 2012
–1.5 million users
–100 plus high profile curators
• Martha Stewart
• Alicia Silverstone
• The Judds
• Bobby Flay
• Cake Boss
–10 million connections
–500k in revenue a week
OpenSky
Tuesday, May 8, 12

5. Offices
• Headquarters in Manhattan
• Satellite offices across the United States
–Nashville
–New Hampshire
–Portland
–San Francisco
OpenSky
Tuesday, May 8, 12

6. Technology Overview
• PHP (DEVO)
• Symfony2 (Framework)
• Doctrine2 (Database Persistence Libraries)
–Object Relational Mapper + MySQL
–Object Document Mapper + MongoDB
• Java (OSIS)
–Mule (Framework)
–HornetQ (Message Queue)
• MongoDB
• MySQL
• Memcached
• Varnish
OpenSky
Tuesday, May 8, 12

7. Technology Overview
–Apache
–Nginx
–Puppet (server configuration)
–Fabric (deploys)
–Github (source control)
–Jenkins
–pr-nightmare
»ruby bot that integrates GitHub pull requests with jenkins.
–JIRA
–Nagios
–Statsd
–Graphite
OpenSky
Tuesday, May 8, 12

8. Basic System Structure
MongoDB
Secondary
Replication MongoDB
Primary
MongoDB
Secondary
DEVO OSIS
MongoDB
Text
MySQL
Slave
Replication MySQL
Master
web1 web3 web5
MySQL
Slave
hornetq hornetq hornetq
MySQL Group 1
hornetq
cluster
web2 web4 web6
varnish/load
Request nginx
balancer hornetq hornetq hornetq
failover
VIP
Group1
Group 2
hornetq
OpenSky
Tuesday, May 8, 12

9. Databases
• MongoDB
• MySQL
OpenSky
Tuesday, May 8, 12

10. MongoDB
• What do we store in MongoDB?
– Non transactional CMS type data
• Products
• Catalog
• Categories
• Follows
• Offers
• CMS Site Data
• Other misc. non mission critical data
OpenSky
Tuesday, May 8, 12

11. MySQL
• What do we store in MySQL?
–Important transactional data
• Orders
• Inventory
• Stock items
OpenSky
Tuesday, May 8, 12

12. HornetQ
• Cluster of HornetQ nodes
–HornetQ runs on each web node
–DEVO sends messages to HornetQ
–OSIS consumes messages from the HornetQ
cluster and performs actions on the messages
• interact with third party API
• chunk the work and multiple messages to other queues
• upload images to s3
OpenSky
Tuesday, May 8, 12

13. HornetQ Failover
• If the local HornetQ is not available on the
web node it fails over to a VIP
• Protects us from losing messages if we have
an issue with a local hornetq node.
OpenSky
Tuesday, May 8, 12

14. Example
• Image uploads in DEVO admin
–User uploads an image
–Image is stored in MongoDB gridfs temporarily
–Send a message to OSIS about the image
–OSIS downloads the image and sends it to Amazon
–When done OSIS posts back to DEVO to update the database
with the new url
–Image is served from CloudFront
OpenSky
Tuesday, May 8, 12

15. Example
• At OpenSky we listen to the seller.follow event
and perform other actions
–forward the event to OSIS
• send e-mail for the follow
• notify sailthru API of the user following the seller
–log the follow to other databases like an activity
feed for the whole site
–rules engines. When actions like “follow” are
performed we compare the action to a database
of rules and act based on what the rule requires
OpenSky
Tuesday, May 8, 12

16. Why sit behind HornetQ?
• Ability to retry things when they fail
• Keep heavy and long running operations out
of the scope of the web request
• Imagine if your mail service goes down while
users are registering, they will still get the
join e-mail it will just be delayed since we
don’t send the mail directly from DEVO.
Instead we simply forward the user.create
event to OSIS
OpenSky
Tuesday, May 8, 12

17. DEVO
• Main components that make up DEVO
–Symfony2
–Doctrine2 ORM
–Doctrine MongoDB ODM
OpenSky
Tuesday, May 8, 12

18. Domain Model
• Plain old PHP objects
/** @ODMDocument(...) */
class Seller
{
/** @ODMId */
–MongoDB Documents protected $id;
// ...
–ORM Entities }
/** @ODMDocument(...) */
class User
{
/** @ODMId */
protected $id;
/** @ORMEntity(...) */ // ...
}
class Order
class SellerFollow
{
{
/** @ORMId */ // ...
protected $id;
/** @ODMReferenceOne(targetDocument="User") */
/** @ODMObjectId */ protected $user;
protected $productId;
/** @ODMReferenceOne(targetDocument="Seller") */
/** @GedmoReferenceOne( protected $seller;
}
* type="document",
/** @ODMDocument(...) */
* targetDocument="Product", class Product
* identifier="productId" {
* ) /** @ODMId */
*/ protected $id;
protected $product;
// ...
// ... }
}
OpenSky
Tuesday, May 8, 12

19. Separate model and persistence
–Easier to test
–Don’t need connection or mock connection in
order to test model since it is just POPO(plain old
php objects)
–More flexible and portable. Make your model a
dependency with a submodule
• share across applications that are split up
• more controlled change environment for the model and
database
OpenSky
Tuesday, May 8, 12

20. Working with model
$user = $dm->getRepository('User')
->createQueryBuilder()
->field('email')->equals('jonwage@gmail.com')
->getQuery()
->getSingleResult();
$seller = $dm->getRepository('Seller')
->createQueryBuilder()
->field('slug')->equals('marthastewart')
->getQuery()
->getSingleResult();
$sellerFollow = new SellerFollow($seller, $user);
OpenSky
Tuesday, May 8, 12

21. Thin Controllers
• Keep controllers thin and delegate work to
PHP libraries with clean and intuitive APIs
• A controller action in DEVO looks something
like this:
class FollowController
{
// ...
public function follow($sellerSlug)
{
// $seller = $this->findSellerBySlug($sellerSlug);
// $user = $this->getLoggedInUser();
$this->followManager->follow($seller, $user);
}
// ...
}
OpenSky
Tuesday, May 8, 12

22. Decoupled Code
• Functionality is abstracted away in libraries
that are used in controllers.
class FollowManager
{
// ...
public function follow(Seller $seller, User $user)
{
// ...
}
}
OpenSky
Tuesday, May 8, 12

23. Decoupled Code
• Decoupled code leads to
–better unit testing
–easier to understand
–easier maintain
–evolve and add features to
–longer life expectancy
OpenSky
Tuesday, May 8, 12

24. DEVO Events
• In DEVO we use events heavily for managing
the execution of our own app code but also
for communicating between systems
<service id="app.listener.name" class="AppListenerSellerFollowListener">
<tag name="kernel.event_listener" event="seller.follow" method="onSellerFollow" />
</service>
class FollowManager
{
// ...
public function follow(Seller $seller, User $user)
{
// ...
$this->dispatcher->notify(new Event($seller, 'seller.follow', array(
'user' => $user
)));
}
}
OpenSky
Tuesday, May 8, 12

25. Listening to events
• Now we can listen to seller.follow and
perform other actions when it happens.
– Create SellerFollowListener::onSellerFollow()
class SellerFollowListener
{
/**
* Listens to 'seller.follow'
*/
public function onSellerFollow(EventInterface $event)
{
$seller = $event->getSubject();
$user = $event['user'];
// do something
}
}
OpenSky
Tuesday, May 8, 12

26. Forwarding events to OSIS
• We also have a mechanism setup in DEVO to
forward certain events to OSIS
• Configure EventForwarder to forward the seller.follow
and seller.unfollow events
<parameter key="memoryqueue.queue.seller">jms.queue.opensky.seller</parameter>
<service id="follow.event_forwarder" class="EventForwarder" scope="container">
<tag name="kernel.event_listener" event="seller.follow" method="forward" />
<tag name="kernel.event_listener" event="seller.unfollow" method="forward" />
<argument>%memoryqueue.queue.seller%</argument>
<argument type="service" id="serializers.sellerFollower" />
<argument type="service" id="memoryqueue.client" />
</service>
OpenSky
Tuesday, May 8, 12

27. The EventForwarder
class EventForwarder
{
protected $client;
protected $queueName;
protected $serializer;
protected $logger;
public function __construct($queueName, AbstractSerializer $serializer, ClientInterface $client, LoggerInterface $logger)
{
$this->serializer = $serializer;
$this->queueName = $queueName;
$this->client = $client;
$this->logger = $logger;
}
public function forward(Event $event)
{
$headers = array(
BasicMessage::EVENT_NAME => $event->getName(),
BasicMessage::HOSTNAME => php_uname('n'),
);
if ($event->has('delay')) {
$headers['_HQ_SCHED_DELIVERY'] = (time() + $event->get('delay')) * 1000;
}
$parameters = $this->serializer->toArray($event->getSubject());
$message = new BasicMessage();
$message->setHeaders($headers);
$message->setQueueName($this->queueName);
$message->setParameters($parameters);
if ($this->logger) {
$this->logger->info(sprintf('Forwarding "%s" event to "%s"', $event->getName(), $this->queueName));
$this->logger->debug('Message parameters: '.print_r($parameters, true));
}
$this->client->send($message);
}
}
OpenSky
Tuesday, May 8, 12

28. Development Lifecycle
OpenSky
Tuesday, May 8, 12

29. JIRA
• Manage product/development requests and
workflow
–Managing releases
–What QA needs to test in each release
–What a developer should be working on
OpenSky
Tuesday, May 8, 12

30. github
• Pull requests
–Code review/comments
–Integration with jenkins for continuous
integration
• In house github
–Keep sensitive information safe and in our control
• passwords mainly
–Ability to deploy when github has issues
• git flow and project branches
OpenSky
Tuesday, May 8, 12

31. pr-nightmare
• Robot written in ruby by Justin Hileman
(@bobthecow)
–Monitors pull requests on github
–Runs jenkins build for pull requests when first
created and each time it is changed and
comments on the pull request with success or
failure
–Keeps our build always stable
–pr-nightmare runs on a beast of a build server so
tests run fast and in groups so you get feedback
fast
OpenSky
Tuesday, May 8, 12

32. fabric
• One click deploys
–Makes deploying trivial
–Get new functionality out in to the wild fast
–Hotfix issues quickly
• Example commands
$ fab staging proxy.depp
$ fab staging cron.stop
$ fab staging ref:release/3.5.1 deploy
OpenSky
Tuesday, May 8, 12

33. No downtime deploys
• Web nodes split in two groups
–group1
• web1
• web3
• web5
–group2
• web2
• web4
• web6
OpenSky
Tuesday, May 8, 12

34. Deploy to one group at a time
Start the deploy, build everything and distribute it to the web nodes but don’t make it live
$ fab prod ref:v3.5.0 deploy.start
Pull group2 from the load balancer so it is not receiving any traffic
$ fab prod proxy.not_group1
Finish deploy on the out nodes (group1)
$ fab prod:out ref:v3.5.0 deploy.finish
Test group1 and make sure everything is stable.
Flip the groups in the load balancer so group1 with the new version starts getting traffic and group2 stops getting traffic
$ fab prod proxy.flip
Finish deploy on the out nodes (group2)
$ fab prod:out ref:v3.5.0 deploy.finish
Make all nodes live
$ fab prod proxy.all
OpenSky
Tuesday, May 8, 12

35. Depped
• When a deploy requires downtime we “depp”
the site. Basically, we show a page with
pictures of Johnny Depp.
• Depped:
–To be put under the spell of Johnny Depp's
charming and beautiful disposition.
• Depp the site with fabric and no nodes will
receive traffic
$ fab prod proxy.depp
OpenSky
Tuesday, May 8, 12

36. Database Migrations
• Deploys often require a migration to the
database
–Add new tables
–Add new fields
–Migrate some data
–Rename fields
–Remove deprecated data
–Anything else you can imagine
• Try to make migrations backwards compatible
to avoid downtime
• Eventual migrations
• Migrate data on read and migrate when updated.
OpenSky
Tuesday, May 8, 12

37. Database Migrations
• Doctrine Migrations library allows database
changes to be managed with PHP code in
github and deployed with fabric
• Generate a new migration in DEVO
$ ./app/console doctrine:migrations:generate
class Version20120330114559 extends AbstractMigration
{
public function up(Schema $schema)
{
}
public function down(Schema $schema)
{
}
}
OpenSky
Tuesday, May 8, 12

38. Database Migrations
• Add SQL in the up() and down() methods.
class Version20120330114559 extends AbstractMigration
{
public function up(Schema $schema)
{
$this->addSql('ALTER TABLE stock_items ADD forceSoldout TINYINT(1) NOT NULL DEFAULT 0');
}
public function down(Schema $schema)
{
$this->addSql('ALTER TABLE stock_items DROP COLUMN forceSoldout');
}
}
• down() allows you to reverse migrations
OpenSky
Tuesday, May 8, 12

39. Database Migrations
• Deploy migrations from the console
$ ./app/console doctrine:migrations:migrate
• Deploying with fabric executes migrations if
any new ones are available
OpenSky
Tuesday, May 8, 12

40. Database Migrations
• Our migrations live in a standalone git
repository
• Linked to DEVO with a submodule
• Allows managed database changes to be
deployed standalone from a full fabric deploy
which requires pulling a group out of the load
balancer.
OpenSky
Tuesday, May 8, 12

41. Use third party services
• Don’t reinvent the wheel outside of your core
competency
–Sailthru - transactional and marketing emails
–Braintree - credit card processing
–Vendornet - supplier drop-ship system
–Fulfillment Works - managed warehouse
–Kissmetrics & Google Analytics - analytics
–Chartbeat - real time statistics
OpenSky
Tuesday, May 8, 12

42. Social Integration
• Facebook comments
–Utilize facebook comments system instead of
rolling our own
–Integrate with our data model via FB.api for local
comments storage
• Facebook timeline
–Post OpenSky actions/activity to users facebook
timeline
• Facebook sharing
• Pinterest sharing
• Twitter sharing
OpenSky
Tuesday, May 8, 12

43. Reporting/Data Warehouse
MongoDB
ETL
MySQL Braintree
Replication ETL
MySQL
Data
Warehouse
ETL ETL
Fulfillment
Vendornet
Works
Warehouse
Databases
views/procs
flight_deck
mongo data mysql slave rollups/aggregates
jetstream_mongo opensky_devo atmosphere
OpenSky
Tuesday, May 8, 12

44. flight_deck
• DEVO and other applications only need access
to flight_deck
–Set of stored procedures that run on cron,
updating stats, aggregates, rollups, etc.
–MySQL views to expose the data needed for
dashboards, reports and other reporting user
interfaces.
OpenSky
Tuesday, May 8, 12

45. Internal communications
–IRC
• Day to day most real time communication between
teams is done on IRC
–Jabber
–Github Pull Request Comments
• All code review is done in pull request comments
–Mumble
• Push to talk voice chat used for fire fighting and deploys
–E-Mail lists
OpenSky
Tuesday, May 8, 12

46. Mumble
• http://www.mumble.com
–Hosted mumble servers that are very affordable
OpenSky
Tuesday, May 8, 12

47. Questions?
Jonathan H. Wage
http://twitter.com/jwage
http://github.com/jwage
We’re hiring! jwage@opensky.com
PHP and JAVA Engineers
System Administrators
Frontend Engineers (Javascript, jQuery, HTML, CSS)
Quality Assurance (Selenium, Maven)
Application DBA (MySQL, MongoDB)
OpenSky
Tuesday, May 8, 12