Discover Pinterest Engineering

Agenda

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Mobile & Growth: Monetization & Data:

Deploying & Shipping Code:

Wendy & Dannie

Pawel

Chris & Jeremy

Wendy LuMobile

Scaling User Education on MobileThe Experience Framework

Dannie ChuGrowth

User Education

Motivation?

User Education leads to Engagement

First Pin Education

Challenges

1. Preserve a great user experience

Conflicting Education

Never-ending Stream of Nags

Nag that never goes away

2. Targeting

Are you a new user? Invite some friends!

Do you have an empty homefeed? Make it better!

3. Rapid Experimentation

Experiment with messaging w/o requiring a release

4. Keep the client code clean

Solution?

The Experience Framework

Conflicting Experiences

Experiences and PlacementsNag Placement Home view Placement

Pin Tutorial Card Placement

AB Experimentation, Simple Client Code

Experiences are delivered to the client at runtime

Experience Framework

Decision Engine

Configuration

Handlers

Admin DashboardAPI

Servers

AB Experiments Framework Kafka

(logging)HBase

(User States, Experience States)

API ServersAPI ServersCascading/ MapRed

User State

Batch Loader

Clients

SDK

SDK

What experience should the user see?

Experience Framework

Deep Dive: Nags

What are nags?

• Important information which we occasionally display at the top of a user’s feed•Can be a Call to Action “Confirm

your email” or an announcement “You can now add a map to any board!”

Enter: The Experience Framework

Enter: The Experience Framework

•Each time we reload the home feed, ask the experience framework: What should I show in this nag?

Single Nag Manager that relies on the experience framework to give it the contents to render

Nag Manager

•Experiment with nag messaging, call to actions, images•Add any new nag dynamically, controlled from the backend.•Cool-down management - should not see more than one nag in a set

period of time

What does that nag data look like?Handling actions

"bg_img_url_2x" = "http://mobile-assets.pinterest.com/iphone/nags/invite-mail@2x.png"

"title_text" = "Pinspire your friends!"

"detailed_text" = "Know someone who'd like Pinterest? Invite them along."

"button1_text" = "No, Thanks”!"button1_uri" = ""!

"button2_text" = "Invite Friends"!"button2_uri" = "pinterest://invite_friends"

Handling Actions

•All initialization and presentation of view controllers is handled through a central “Navigation Manager.”• Centralizes code to create and present view controllers• Consistency to other platforms for deep links

•Allows dynamic insertion of nags from the backend without having to write new client code and submit a new release

[[NavigationManager sharedManager] handleURL:[NSURL URLWithString:@“pinterest://invite_friends]];

Navigation Manager

self.presentationDelegate

presentInviteFriends

Deep Dive: New User Experience

New User ExperienceWhat is NUX?

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•The set of initial tutorials and education presented to a user after they register

Personalize a user’s content immediately after signupConnect with Friends Choose Interests

Next, teach users how to Pin

Experiment between classic user ed and NUX

Experiment between classic user ed and NUX

•When doing experiments where we need to call the network to get the user’s treatment group, need to make sure we’re not adding perceived latency• Structure view controllers in a way that you can asynchronously load in the modules

dependent on the treatment group• If need to transition to different view controllers, set a time out in which we transition

to the control treatment• “Be Fast or Fail Fast”

1 step vs. 2 steps vs. 3 stepsExperiment with different versions of NUX

Experiment with different versions of NUX

•Backend controls all strings, allowing us to dynamically experiment with different text (Messaging, titles, calls-to-action)

steps = ( { "continue_button_text" = Continue; "detailed_text" = "Tap a network to find people who share your interests."; "follow_button_text" = "Follow selected people"; step = 1; "title_text" = "First things first"; "total_steps" = 2; }, { "completion_message" = "Finding Pins for you..."; "continue_button_text" = "Tap at least {0} more to continue"; "detailed_text" = "Tap whatever you're interested in these days."; "finish_text" = Finish; "num_interests" = 5; "skip_text" = "Pinterest is much more interesting when you tell us what you like."; step = 2; "title_text" = "Pick 5 interests"; "total_steps" = 2; } );

After signup, request all data for NUXEnter: Experience Framework

Supports dynamic number and order of stepsNUXViewController : UINavigationController

•Maps an array of display data to an array of view controllers

•Protocol method advanceToNextStep called by each child view controller• Checks the array it keeps for the next view controller to push

JSON dict for Intro

JSON dict for Friend Selector

JSON dict for Interests Selector

NUXIntroViewController

NUXConnectViewController

NUXInterestsViewController

Wins from Experience Framework

•Single place in the backend that manages all experiences for all platforms•Dynamically trigger display of content•Conflict resolution for educations that touch the same views•Experiment with flows, messaging, and images

engineering.pinterest.com

Pawel GarbackiSoftware Engineer, Monetization

Pinterest SecorZero-data-loss log persistence service

Pinterest is a data driven company

•Data matters• 100+ experiments active at a given point in time• 1500+ tracked metrics• 200+ log types

We produce a lot of data

•We produce a lot of data• PBs of data in S3, growing by Tens of TB a day• Hundreds of production hadoop jobs, processing about half a PB of data each day

Singer (logging agent)

App

Data pipeline

Local Disk

S3Kafka (log collector)

Secor (log saver)

Storm (realtime

stats)

Hive (hadoop analytics)

Redshift (ad hoc queries)

Singer (logging agent)

App

Local Disk

S3Kafka (log collector)

Secor (log saver)

Storm (realtime

stats)

Hive (hadoop analytics)

Redshift (ad hoc queries)

Data pipeline20B messages/day

Kafka 101

•Distributed pub-sub service•Designed for high throughput Producer Producer Producer

Consumer Consumer Consumer

Kafka cluster

Anatomy of a topic

•Topic is a category to which messages are published•Partition is a ‘shard’ of a topic controlling the level of consumption parallelism•Messages are assigned unique identifiers called offsets

1 2 3 4 5 6 7 8 9 10 11 12

1 2 3 4 5 6 7 8 9

1 2 3 4 5 6 7 8 9 10 11 12

Writes

Partition 0

Partition 1

Partition 2

Save the day

•Kafka is optimized for local writes•Local disk capacity is good for a few

days worth of data•Data needs to be saved (at least) daily

to long term storage - Amazon S3

How soon is “eventually”

•Amazon S3 is a cloud file system•Eventual consistency model• No guarantees on when uploaded data will become visible to the readers• No monotonicity - data available in the past may magically disappear

Secor design guidelines

•Objectives:• Persist Kafka logs to S3• Cause no data loss• Work properly with eventual consistency model

•Properties:• Horizontal scalability• Fault tolerance• Customizability

No-S3-reads principle

•Secor never reads data from S3• Lightweight metadata is stored in strongly

consistent state repository

•Strategic choice of file names• s3n://logs/<topic>/

<generation>_<partition>_<start_offset>• <generation> represents software compatibility

version• Inconsistencies introduced by consumer failures

get fixed automatically by file overwrites

Date clustering

•Data processing tools rely on date-partitioned directory structure• s3n://logs/event/dt=2014-04-04/

•Timestamps extracted from messages on the fly•Support for pluggable parsers for thrift,

json, etc.

https://github.com/pinterest/secor

Chris Danford (@chrisdanford) Jeremy Stanley (@rouxbot)Web Team

From Development to ProductionThe life of web features

Develop Review Deploy Measure

Develop Review Deploy Measure

Developing - Ideal state

• able to iterate quickly• easy errors caught automatically• easy-to-understand and powerful abstractions

Fast iterationDeveloping

•Build tasks and dependencies modeled as a graph• “cumberbatch” watches for changes of file contents• “orchestrator” knows tasks and dependencies•build the minimum tasks to heal damage in the graph•maximize parallelization of tasks•built on Grunt - access to large library of build tasks

Self-healing build graphsprite/*.png

sprite task

sprite.png sprite.scss

Sass task

component/*.scss

components.css

imagemin task Autoprefixer task CSSlint task

Self-healing build graphsprite/*.png

sprite task

sprite.png sprite.scss

Sass task

component/*.scss

components.css

imagemin task Autoprefixer task CSSlint task

Self-healing build graphsprite/*.png

sprite task

sprite.png sprite.scss

Sass task

component/*.scss

components.css

imagemin task Autoprefixer task CSSlint task

Self-healing build graph, example 2sprite/*.png

sprite task

sprite.png sprite.scss

Sass task

component/*.scss

components.css

imagemin task Autoprefixer task CSSlint task

Self-healing build graph, example 2sprite/*.png

sprite task

sprite.png sprite.scss

Sass task

component/*.scss

components.css

imagemin task Autoprefixer task CSSlint task

LintingDeveloping

• catches easy bugs• enforces consistent style•pyflakes•pep8• jshint•CSSLint• custom RegEx linting

RegEx-based linter

$(‘.item’).addClass(‘selected’);

BoardPicker.js

this.$(‘.item’).addClass(‘selected’);

Static analysis / type safetyDeveloping

•Google Closure Compiler• template static analysis• validation of template inheritance• extract used option variable names

•Thrift clients for service calls (Python) and shared constants (JavaScript)

Closure Compiler - type safety

Generated constants from Thrift

AbstractionsDeveloping

• component framework• styles are scoped to the component• DOM access is scoped to the component’s DOM• “events up, methods down” • scaffolding script

• live component catalog - discovery of existing components• autoprefixer, spriting - remove boilerplate

component catalog

spriting

.thumbsUpButton {! @include inline-image(‘sprites/main/thumbUp');!}

Usage

Develop Review Deploy Measure

Reviewing - Ideal state

• the most-relevant person is reviewing changes• integration-type issues are caught

Code ReviewsReviewing

• local test runner script runs Jasmine and Node tests parallelized• “PR watcher” tool - visibility of relevant PRs• code review process - R+, E+

Parallelized Jasmine tests in PhantomJS

Github Watcher tool

Integration problems are caughtReviewing

•PRs trigger a build and tests - 3 minutes• latest.pinterest.com is continuously deployed from “head”•Selenium integration tests run against every deploy

Pull request builds

Selenium

Develop Review Deploy Measure

Deploying - Ideal state

• code deploys are invisible to users• frequent and non-disruptive to developers• immediate rollback when there’s a problem

User experienceDeploying

• stickiness to a version• flip nearly instantaneously between builds• reduce version thrashing• worry less about (style mismatches, JS errors due to data format mismatch with

server)

• asset versioning

Serving multiple application versions

new!sessions

old!sticky!sessions

A B

all!sessions

B

1 2

Serving multiple application versions, cont’d

3 4

new!canary!sessions

all!non-canary!sessions

B C

new!sessions

old!sticky!sessions

B C

Asset versioninglogo.png

rename

hash file!contents

logo.59aa9183.png

bundle.css

background-image: logo.png

background-image: logo.59aa9183.png

update references

bundle.css

bundle.907389d8.css

rename

hash file!contents

When things go wrongDeploying

• experiments dashboard - turn off experiments instantaneously• version rollback is nearly instantaneous

Develop Review Deploy Measure

Monitoring healthA/B Dashboard

•A/B dashboard key metrics•Sentry •Stats dashboard•Alarms - Monit, PagerDuty

A/B Dashboard

Sentry

Sentry error emails

Results

Results

•5 engineers on web team• all teams at Pinterest developing their own web features on our platform• components re-used across teams•2 scheduled deploys a day• anomalies in key metrics surfaced immediately•100s of simultaneous experiments