Ruby Can Too Scale: Highly Performant Microservices in Ruby (Confoo Vancouver 2016)

Ruby developers have known for years that our beloved language is one of the most joyful to use. And yet, “Ruby Can’t Scale” seems to be a daily article on Hacker News. Tim Krajcar presents some tips and tricks that he’s learned at New Relic writing Ruby services that scale to hundreds of thousands of requests per minute.

Topics include:

* Building performance into your architecture from your first commit
* Where to invest precious development hours to realize the most performance value
* Which frameworks to use, and which to avoid, when working at scale
* Designing to avoid cascading failures when building highly interdependent services

Transcript

1. Ruby Can Too Scale:
   Highly Performant Microservices in Ruby
   Tim Krajcar
   

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2. April 2015
   

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3. TimKrajcar
   \
   

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4. TimKrajcar
   This document and the information herein (including any information that may be incorporated by reference) is provided for
   informational purposes only and should not be construed as an offer, commitment, promise or obligation on behalf of New Relic, Inc.
   (“New Relic”) to sell securities or deliver any product, material, code, functionality, or other feature. Any information provided hereby
   is proprietary to New Relic and may not be replicated or disclosed without New Relic’s express written permission.
   Such information may contain forward-looking statements within the meaning of federal securities laws. Any statement that is not a
   historical fact or refers to expectations, projections, future plans, objectives, estimates, goals, or other characterizations of future
   events is a forward-looking statement. These forward-looking statements can often be identified as such because the context of the
   statement will include words such as “believes,” “anticipates,” “expects” or words of similar import.
   Actual results may differ materially from those expressed in these forward-looking statements, which speak only as of the date
   hereof, and are subject to change at any time without notice. Existing and prospective investors, customers and other third parties
   transacting business with New Relic are cautioned not to place undue reliance on this forward-looking information. The achievement
   or success of the matters covered by such forward-looking statements are based on New Relic’s current assumptions, expectations,
   and beliefs and are subject to substantial risks, uncertainties, assumptions, and changes in circumstances that may cause the actual
   results, performance, or achievements to differ materially from those expressed or implied in any forward-looking statement. Further
   information on factors that could affect such forward-looking statements is included in the filings we make with the SEC from time
   to time. Copies of these documents may be obtained by visiting New Relic’s Investor Relations website at ir.newrelic.com or the
   SEC’s website at www.sec.gov.
   New Relic assumes no obligation and does not intend to update these forward-looking statements, except as required by law. New
   Relic makes no warranties, expressed or implied, in this document or otherwise, with respect to the information provided.
   

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5. TimKrajcar
   

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6. TimKrajcar
   why this talk?
   

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7. TimKrajcar
   "ruby can't scale"
   

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8. –Johnny Appleseed
   

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9. –Johnny Appleseed
   

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10. –Johnny Appleseed
    

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11. TimKrajcar
    "ruby can't scale"
    

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12. TimKrajcar
    "rails can't scale"
    

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13. TimKrajcar
    second system
    effect
    

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14. –Johnny Appleseed
    

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15. –Johnny Appleseed
    and, even more importantly, stack
    

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16. TimKrajcar
    why ruby?
    

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17. TimKrajcar
    expressive programming language
    =
    fun to write code
    =
    I want to write more of it
    

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18. TimKrajcar
    expressive programming language
    =
    fun to write code
    =
    I want to write more of it
    productivity!!
    
    

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19. TimKrajcar
    things not covered
    

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20. TimKrajcar
    1. database tuning
    

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21. TimKrajcar
    1. database tuning
    2. caching
    

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22. TimKrajcar
    1. database tuning
    2. caching
    3. network optimization
    

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23. TimKrajcar
    1. database tuning
    2. caching
    3. network optimization
    4. browser-y things
    

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24. TimKrajcar
    microservices at New
    Relic
    

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25. TimKrajcar
    ~110 total services
    

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26. TimKrajcar
    some not so micro
    

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27. TimKrajcar
    Ruby:
    common for prototypes
    

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28. TimKrajcar
    service templates and
    app auto-generation
    

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29. –Johnny Appleseed
    

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30. TimKrajcar
    stereotypical example:
    customer permissions service
    

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31. –Johnny Appleseed
    

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32. –Johnny Appleseed
    

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33. PERFORMANCE FROM THE
    FIRST COMMIT
    

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34. –Johnny Appleseed
    Structured programming with 'go to' statements
    Donald E. Knuth
    COMPUTING SURVEYS, DECEMBER 1974
    

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35. –Johnny Appleseed
    We should forget about small
    efficiencies, say about 97% of the
    time: premature optimization is the
    root of all evil.
    

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36. –Johnny Appleseed
    Yet we should not pass up our opportunities in
    that critical 3%. A good programmer will not be
    lulled into complacency by such reasoning,
    [and] will be wise to look carefully at the critical
    code.
    

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37. TimKrajcar
    benchmarking
    methodologies matter
    

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38. TimKrajcar
    app server time
    vs
    request queuing
    

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39. –Johnny Appleseed
    

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40. –Johnny Appleseed
    

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41. TimKrajcar
    X-Request-Start
    HTTP header
    

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42. TimKrajcar
    X-Amzn-Trace-Id
    HTTP header
    

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43. TimKrajcar
    test suite tools
    

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44. TimKrajcar
    minitest-perf
    https://github.com/mrsimo/minitest-perf
    

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45. > bundle exec minitest-perf
    Slowest individual tests
    1210.00ms | NewRelic::Agent::AgentTest#test_after_fork_should_
    1190.78ms | LicenseTest#test_for_scary_license_terms
    1034.58ms | NewRelic::Agent::Agent::ConnectTest#test_connect_g
    1034.20ms | NewRelic::Agent::Agent::ConnectTest#test_logging_c
    1032.60ms | NewRelic::Agent::Agent::ConnectTest#test_environme
    1031.61ms | NewRelic::Agent::Agent::ConnectTest#test_connect_s
    1030.49ms | NewRelic::Agent::Agent::ConnectTest#test_connect_s
    730.88ms | OrphanedConfigTest#test_all_default_source_config_
    455.05ms | NewRelic::Agent::MetricStatsTest#test_record_scope
    434.18ms | NewRelicServiceTest#test_json_marshaller_should_ha
    

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46. Slowest test suites
    638.87ms | 2 | LicenseTest
    293.86ms | 3 | OrphanedConfigTest
    193.41ms | 27 | NewRelic::Agent::Agent::ConnectTest
    191.36ms | 1 | NewRelic::Agent::Threading::BacktraceServic
    130.64ms | 14 | NewRelic::Agent::PipeChannelManagerTest
    118.76ms | 14 | PipeServiceTest
    111.14ms | 4 | DispatcherTest
    32.82ms | 63 | NewRelic::Agent::AgentTest
    25.50ms | 20 | NewRelic::Agent::MetricStatsTest
    19.37ms | 12 | NewRelic::Agent::UtilizationDataTest
    

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47. TimKrajcar
    framework choices
    

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48. TimKrajcar
    framework choices
    reductions
    

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49. –Johnny Appleseed
    

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50. TimKrajcar
    example!!
    

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51. TimKrajcar
    a typical Ruby microservice:
    REST DB-to-JSON API
    https://github.com/tkrajcar/ruby-can-too-scale
    

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52. TimKrajcar
    a typical Ruby microservice:
    REST DB-to-JSON API
    https://github.com/tkrajcar/ruby-can-too-scale
    !! warning: YOLOCODE !!
    

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53. TimKrajcar
    •Rails 4.2.6 straight outta rails new + Puma +
    nginx
    •JSON only, using scaffolded controller & model
    •testing #index (~25kb) and #show (<1 kb)
    •read-only
    •Dedicated EC2 c3.large instances (2 vCPUs)
    •Postgres on its own dedicated RDS instance
    •30 users as fast as possible (separate instance)
    

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54. TimKrajcar
    best metric:
    client requests per minute
    

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55. TimKrajcar
    #index
    /articles.json
    #show
    /articles/1.json
    Stock Rails scaffolding 4,211 18,011
    

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56. TimKrajcar
    #index
    /articles.json
    #show
    /articles/1.json
    Stock Rails scaffolding 4,211 18,011
    No jbuilder templates
    4,561
    +8.3%
    18,909
    +4.9%
    

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57. TimKrajcar
    #index
    /articles.json
    #show
    /articles/1.json
    Stock Rails scaffolding 4,211 18,011
    No jbuilder templates
    4,561
    +8.3%
    18,909
    +4.9%
    oj gem
    5,548
    +21.6%
    19,714
    +9.4%
    

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58. TimKrajcar
    #index
    /articles.json
    #show
    /articles/1.json
    Stock Rails scaffolding 4,211 18,011
    No jbuilder templates
    4,561
    +8.3%
    18,909
    +4.9%
    oj gem
    5,548
    +21.6%
    19,714
    +9.4%
    Sequel instead of
    ActiveRecord
    7,035
    +26.8%
    22,378
    +13.5%
    

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59. TimKrajcar
    #index
    /articles.json
    #show
    /articles/1.json
    Stock Rails scaffolding 4,211 18,011
    No jbuilder templates
    4,561
    +8.3%
    18,909
    +4.9%
    oj gem
    5,548
    +21.6%
    19,714
    +9.4%
    Sequel instead of
    ActiveRecord
    7,035
    +26.8%
    22,378
    +13.5%
    Sinatra
    (with Sequel and oj)
    13,245 85,017
    

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60. TimKrajcar
    #index
    /articles.json
    #show
    /articles/1.json
    Stock Rails scaffolding 4,211 18,011
    No jbuilder templates
    4,561
    +8.3%
    18,909
    +4.9%
    oj gem
    5,548
    +21.6%
    19,714
    +9.4%
    Sequel instead of
    ActiveRecord
    7,035
    +26.8%
    22,378
    +13.5%
    Sinatra
    (with Sequel and oj)
    13,245 85,017
    
    
    

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61. TimKrajcar
    tl;dr:
    use Sinatra and Sequel
    

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62. DIVING DEEPER
    

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63. TimKrajcar
    Derailed Benchmarks
    https://github.com/schneems/derailed_benchmarks
    

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64. > bundle exec derailed bundle:mem
    TOP: 46.5625 MiB
    activeadmin: 17.5156 MiB
    active_admin: 17.5039 MiB
    meta_search: 6.2773 MiB
    meta_search/searches/active_record: 1.707 MiB
    meta_search/builder: 1.5938 MiB
    meta_search/where: 1.0977 MiB
    polyamorous: 0.4688 MiB
    active_admin/comments: 3.6055 MiB
    active_admin/comments/views: 1.375 MiB
    active_admin/views: 1.2305 MiB (Also required by:
    active_admin/comments/views/active_admin_comments)
    /Users/tkrajcar/.rbenv/versions/2.1.7/lib/ruby/gems/
    2.1.0/gems/activeadmin-0.6.3/lib/active_admin/views/components/
    paginated_collection.rb: 0.3125 MiB
    bourbon: 3.3438 MiB
    

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65. > bundle exec derailed bundle:objects
    Measuring objects created by gems in groups [:default, "production"]
    Total allocated: 72414462 bytes (425465 objects)
    Total retained: 24736698 bytes (44790 objects)
    allocated memory by gem
    -----------------------------------
    27407703 activesupport-3.2.22.2
    9240545 erubis-2.7.0
    5722758 actionpack-3.2.22.2
    3287857 activerecord-3.2.22.2
    3176375 haml-4.0.5
    1728840 meta_search-1.1.3
    1300638 devise-1.5.4
    1216006 2.1.7/lib
    1016914 formtastic-2.2.1
    993225 activeadmin-0.6.3
    

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66. TimKrajcar
    Stackprof
    https://github.com/tmm1/stackprof
    

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67. –Johnny Appleseed
    

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68. TimKrajcar
    other interpreters
    

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69. DESIGNING TO AVOID
    CASCADING FAILURES
    

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70. TimKrajcar
    timeouts
    

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71. –Johnny Appleseed
    

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73. TimKrajcar
    Timeout
    

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74. require 'timeout'
    result = begin
    Timeout::timeout(0.5) { do_a_possibly_slow_thing }
    rescue Timeout::Error
    # log/notify about the timeout
    0
    end
    

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78. TimKrajcar
    circuit breaker pattern
    

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79. –Johnny Appleseed
    http://martinfowler.com/bliki/CircuitBreaker.html
    

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80. TimKrajcar
    cb2
    https://github.com/pedro/cb2
    

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81. require 'cb2'
    breaker = CB2::Breaker.new(
    service: "cashwings", # identify each circuit breaker individually
    duration: 60, # in this amount of seconds...
    threshold: 5, # ...this % of errors will open the breaker
    reenable_after: 600, # once opened, how long until we try again
    redis: Redis.new) # uses Redis to keep track by service name
    

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82. require 'cb2'
    breaker = CB2::Breaker.new(
    service: "cashwings", # identify each circuit breaker individually
    duration: 60, # in this amount of seconds...
    threshold: 5, # ...this % of errors will open the breaker
    reenable_after: 600, # once opened, how long until we try again
    redis: Redis.new) # uses Redis to keep track by service name
    
    

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83. begin
    breaker.run do
    some_api_request()
    end
    rescue CB2::BreakerOpen
    # log/notify about the breaker opening!
    alternate_response()
    end
    

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84. TimKrajcar
    parallelize
    

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85. TimKrajcar
    parallelize everything
    especially HTTP
    

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86. TimKrajcar
    Typhoeus::Hydra
    https://github.com/typhoeus/typhoeus
    

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87. require 'typhoeus'
    request1 = Typhoeus::Request.new("http://example.com/1.json")
    request2 = Typhoeus::Request.new("http://example.com/2.json")
    hydra = Typhoeus::Hydra.new
    hydra.queue(request1)
    hydra.queue(request2)
    hydra.run # blocks here until queue finishes
    puts "Request 1 status #{request1.response.code}"
    puts "Request 2 status #{request2.response.code}"
    

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88. TimKrajcar
    background everything*
    *unless you can't
    

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89. TimKrajcar
    https://github.com/mperham/sidekiq
    

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90. # app/workers/welcome_emailer.rb
    class WelcomeEmailer
    include Sidekiq::Worker
    def perform(email)
    send_email_to(email, "Welcome!")
    end
    end
    # app/controllers/welcome_controller.rb
    def welcome
    # blah blah create a @user
    WelcomeEmailer.perform_async(@user.email)
    end
    

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91. # app/workers/welcome_emailer.rb
    class WelcomeEmailer
    include Sidekiq::Worker
    def perform(email)
    send_email_to(email, "Welcome!")
    end
    end
    # app/controllers/welcome_controller.rb
    def welcome
    # blah blah create a @user
    WelcomeEmailer.perform_async(@user.email)
    end
    doesn't
    block
    

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92. TimKrajcar
    rate limit by client
    

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93. TimKrajcar
    Rack::Throttle
    https://github.com/bendiken/rack-throttle
    

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94. # config/application.rb
    require 'rack/throttle'
    class Application < Rails::Application
    config.middleware.use Rack::Throttle::Hourly, max: 100
    end
    

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95. # config/application.rb
    require 'rack/throttle'
    class Application < Rails::Application
    config.middleware.use Rack::Throttle::Hourly, max: 100
    end
    client = by IP
    or you can define custom client IDs
    

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96. TimKrajcar
    monitoring
    &
    alerting
    

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97. TimKrajcar
    low traffic?
    drive synthetic traffic
    

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98. TimKrajcar
    synthetic-monitor
    https://github.com/johnboyes/synthetic-monitor
    

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100. TimKrajcar
     RECAP!!
     

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101. TimKrajcar
     1. use Ruby to write services, because it's fun!
     2. monitor both request queuing time and app server time
     3. make informed framework decisions (use sinatra)
     4. set real timeouts and use circuit breakers
     5. parallelize everything
     6. background everything
     7. rate limit by client, even for internal clients
     8. drive synthetic traffic to help catch problems right away
     

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102. TimKrajcar
     references
     

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103. TimKrajcar
     Nate Berkopec: nateberkopec.com
     High Scalability: highscalability.com
     Improved Production Stability With Circuit
     Breakers: blog.heroku.com
     

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104. TimKrajcar
     thanks!
     

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