Improving Your Heroku App Performance with Asset CDN and Unicorn

Optimizing rails applications’ performance

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Question

Does anyone know what

f5dd

is?

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What *is Preso is NOT

• not a coding demo or tutorial (strangely)

• not a best practices showcase

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What *is Preso IS

• tips and tricks on tuning rails application

• personal experience

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DisclaimerThere are many other ways to improve app’s performance:

•database performance (indexes, N+1, slow queries)•caching•background processing•changing interpreter, GC•conditional asset loading, etc•removing cruft!

Try them first!

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*is Presentation - Two Parts

• CDN Asset Host using aws*

• unicorn web server*

* Both approaches were tested on heroku, but must work with other hosting solutions

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Sample App

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NewRelic Monitoring

average load time for mobile traffic only, includes iframed ads

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Heroku Dyno Operation

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Step 1 - Rack::Cache

Serving assets from rack::cache is faster, and frees up app instance to serve more requests

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Static Asset Caching# Gemfilegem 'dalli'

# config/application.rbconfig.cache_store = :dalli_store

# config/environments/production.rbconfig.action_dispatch.rack_cache = { :metastore => Dalli::Client.new, :entitystore => 'file:tmp/cache/rack/body', :allow_reload => false}config.serve_static_assets = trueconfig.assets.digest = true

config.action_controller.perform_caching = true# provision Memcache addon on Heroku

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A2er Deploymentshould see entries like this in your log

cache: [GET /assets/application-c0747cab950350f59304a3815f980622.css] miss, storecache: [GET /assets/application-032691d4988a7003c42a10995819a0ce.js] miss, storecache: [GET /assets/s_code.js] miss, store

cache: [GET /assets/application-c0747cab950350f59304a3815f980622.css] freshcache: [GET /assets/application-032691d4988a7003c42a10995819a0ce.js] freshcache: [GET /assets/s_code.js] fresh

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Using Rack::Cache Effect

down from 4.91 / 201 / 2.29 before the change -- not bad for 8 lines of code!

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Step 2 - S3 bucket for assets

heroku instance has more time to serve application code because all assets are served from aws s3

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S3 Bucket for Assets# Gemfilegem "asset_sync" # will push compiled assets into CDN

# Command lineheroku config:add FOG_PROVIDER=AWS \ AWS_ACCESS_KEY_ID=xxx \ AWS_SECRET_ACCESS_KEY=yyy

heroku config:add FOG_DIRECTORY=yourappname-assets

# config/environments/production.rbconfig.action_controller.asset_host = "//#{ENV['FOG_DIRECTORY']}.s3.amazonaws.com"

# make sure to use AssetTagHelper methods (like image_tag)# to ensure assets are properly referenced

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Now, on git push heroku

assets are automatically synced to s3 anytime ON rake assets:precompile

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S3 Bucket effect

down from 4.45 / 179 / 2.43 before the change -- even better!

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Step 3 - AWS CloudFront

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CloudFront Effect

down from 3.85 / 179 / 2.19 before the change -- Awesome!

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Loading Single 5le$ time curl http://careersingear.mobi/assets/application-bdb77a926724ccc3c20b923ab168d89d.js

real 0m0.896suser 0m0.008ssys 0m0.016s

----------------

$ time curl http://d3kd72psxbec02.cloudfront.net/assets/application-bdb77a926724ccc3c20b923ab168d89d.js

real 0m0.293suser 0m0.006ssys 0m0.010s

getting a single application.js file from cloud front is 3x faster

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WebPageTest ResultsBefore

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WebPageTest Results A2er

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Meet Unicorn• HTTp server for Ruby

• Starts one master process

• forks worker processes

• workers handle requests

• master returns

• one port, several concurrent requests

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Server Setup

classic setup nginx -> smart balancer -> pool of mongrels

Unicorn setup nginx -> unix domain socket -> unicorn workers (os handles load balancing)

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Unicorn for Rails App# Gemfilegem 'unicorn'

# Procfileweb: bundle exec unicorn -p $PORT -c ./config/unicorn.rb

# config/application.rbconfig.logger = Logger.new(STDOUT)

# also, add config/unicorn.rb

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Unicorn for Rails App# config/unicorn.rbworker_processes 3timeout 30preload_app true before_fork do |server, worker| if defined?(ActiveRecord::Base) ActiveRecord::Base.connection.disconnect! Rails.logger.info('Disconnected from ActiveRecord') end

if defined?(Resque) Resque.redis.quit Rails.logger.info('Disconnected from Redis') end

end after_fork do |server, worker| if defined?(ActiveRecord::Base) ActiveRecord::Base.establish_connection Rails.logger.info('Connected to ActiveRecord') end if defined?(Resque) Resque.redis = ENV["REDISTOGO_URL"] Rails.logger.info('Connected to Redis') endend

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A2er Implementing Unicorn

down from 3.64 / 46.7 / 1.17 before the change -- good, but also...

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Better Concurrency Handlingrequire 'typhoeus'require "benchmark"

URL = "http://careersingear.mobi"HYDRA = Typhoeus::Hydra.new(max_concurrency: 20)

1000.times do request = Typhoeus::Request.new(URL, method: :get, timeout: 10000) request.on_complete do |response| puts response.code end HYDRA.queue(request)end

Benchmark.bm(7) do |x| x.report("first:") { HYDRA.run }end

# using thin# user system total real# 1.030000 0.380000 1.410000 ( 16.713791)

# using unicorn# user system total real# 1.050000 0.390000 1.440000 ( 7.843766)

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And ...

my app can process six concurrent requests on two heroku dynos

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Riding Unicorn

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To Conclude

• implemented asset cdn

• configured unicorn

• brought down average end user load time from almost 5 sec to 3.5 sec

• app can serve more requests faster and for less $$$

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Creditsdefunkt, unicorn! https://github.com/blog/517-unicorn

heroku dev center, using rack::cache with memcached in rails 3.1+ https://devcenter.heroku.com/articles/

rack-cache-memcached-rails31

Rice, david, using a cdn asset host with rails 3.1 https://devcenter.heroku.com/articles/cdn-asset-

host-rails31

Sikkes, Michael, Complete Guide to serving your Rails assets over S3 with asset_sync http://blog.firmhouse.com/

complete-guide-to-serving-your-rails-assets-over-s3-with-asset_sync

van roijen, michael, more concurrency on a single heroku dyno with the new celadon cedar stack http://

michaelvanrooijen.com/articles/2011/06/01-more-concurrency-on-a-single-heroku-dyno-

with-the-new-celadon-cedar-stack/

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Q & AThis presentation can be found on github github.com/semmin/asset-cdn-and-unicorn-preso

twitter: @status_200

Email: sbagreev@gmail.com

Questions?

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