[RailsConf 2019] Terraforming legacy Rails applications

Video: https://www.youtube.com/watch?v=-NKpMn6XSjU
RailsConf: https://railsconf.com/program/sessions#session-832
GitHub: https://github.com/evilmartians/terraforming-rails

Rails has been around for (can you imagine!) about 15 years. Most Rails applications are no longer MVPs, but they grew from MVPs and usually contain a lot of legacy code that "just works."

And this legacy makes shipping new features harder and riskier: the new functionality have to co-exist with the code written years ago, and who knows what will blow up next?

I've been working on legacy codebases for the last few years, and I found turning legacy code into a legendary code to be a very exciting and challenging process.

I want to share the ideas and techniques I apply to make legacy codebases habitable and to prepare a breeding ground for the new features.

Transcript

1. TERRAFORMING
   LEGACY RAILS APPLICATIONS
   

   View Slide

2. palkan_tula
   palkan RailsConf 2019
   2
   @palkan
   @palkan_tula
   Vladimir Dementyev
   933
   722
   406
   504
   

   View Slide

3. palkan_tula
   palkan RailsConf 2019
   3
   evilmartians.com
   Brooklyn, NY
   Moscow, Russia
   

   View Slide

4. View Slide

5. palkan_tula
   palkan RailsConf 2019
   evl.ms/blog
   5
   

   View Slide

6. palkan_tula
   palkan RailsConf 2019
   evilmartians.com
   6
   

   View Slide

7. palkan_tula
   palkan RailsConf 2019
   FROM SCRATCH
   TWO TYPES OF PROJECTS
   7
   “Build us something cool!”
   SpaceX Star Hopper
   

   View Slide

8. palkan_tula
   palkan RailsConf 2019
   FROM LEGACY
   TWO TYPES OF PROJECTS
   8
   “We’ve built something,
   make it cool!”
   Pepelats from Kin-dza-dza! (Soviet sci-fi)
   That’s my jam!
   

   View Slide

9. palkan_tula
   palkan RailsConf 2019
   LEGACY
   9
   Jason Swett, RubyHACK 2019
   

   View Slide

10. palkan_tula
    palkan RailsConf 2019
    10
    TEAM LEAD
    Evaluate project
    Make ready for
    others to join
    Prepare guidelines
    Captain Zelyonyy (Green),
    The Mystery of the third planet
    

    View Slide

11. THIS TALK
    

    View Slide

12. palkan_tula
    palkan RailsConf 2019
    12
    #BoardGameGeek
    NOT ONLY A DEVELOPER
    

    View Slide

13. palkan_tula
    palkan RailsConf 2019
    13
    TERRAFORMING
    MARS
    “Make Mars habitable!”
    Jacob Fryxelius, 2016
    

    View Slide

14. palkan_tula
    palkan RailsConf 2019
    TERRAFORMING MARS
    14
    Corporations are competing to
    transform Mars into a habitable planet
    by raising temperature, creating a
    breathable atmosphere, and making
    oceans of water.
    As terraforming progresses, more and
    more people will immigrate from Earth
    to live on the Red Planet.
    

    View Slide

15. palkan_tula
    palkan RailsConf 2019
    TERRAFORMING CODE
    15
    Engineers are transforming the legacy
    code into a habitable code by
    optimizing development process, adding
    confidence with tests and linters and
    creating a codeable atmosphere.
    As terraforming progresses, more and
    more people could join the project and
    work on new features.
    

    View Slide

16. palkan_tula
    palkan RailsConf 2019
    16
    MARS
    LANDING
    Setting up the project
    PHASE #1
    

    View Slide

17. palkan_tula
    palkan RailsConf 2019
    17
    GOAL
    PHASE #1
    “Developers should be able
    to run project
    with the least possible
    effort”
    

    View Slide

18. palkan_tula
    palkan RailsConf 2019
    18
    // Make running project locally as
    easy as running a few commands
    $ git clone project/repo.git
    $ cd repo
    $
    $ rails c
    Loading development environment
    2.6.2 (main):0>
    PHASE #1
    GOAL
    

    View Slide

19. DEVELOPMENT
    ENVIRONMENT
    

    View Slide

20. palkan_tula
    palkan RailsConf 2019
    “OLD SCHOOL” DEV ENV SETUP
    20
    Dev setup instructions from yet another Rails project
    

    View Slide

21. palkan_tula
    palkan RailsConf 2019
    “NEW SCHOOL”
    21
    

    View Slide

22. palkan_tula
    palkan RailsConf 2019
    DOCKER FOR DEV
    22
    Repeatable and predictable setup
    Always in sync
    

    View Slide

23. palkan_tula
    palkan RailsConf 2019
    KEEPING ’N SYNC
    23
    

    View Slide

24. palkan_tula
    palkan RailsConf 2019
    DOCKER FOR DEV
    24
    Repeatable and predictable setup
    Always in sync
    Painfully slow on Mac?
    

    View Slide

25. palkan_tula
    palkan RailsConf 2019
    SLOW D4M
    25
    Use :cached folders
    Store assets/bundles in volumes
    Use NFS (if the first two are not enough)
    bit.ly/d4m-nfs
    

    View Slide

26. palkan_tula
    palkan RailsConf 2019
    DOCKER FOR DEV
    26
    Repeatable and predictable setup
    Always in sync
    Painfully slow on Mac Windows
    "
    

    View Slide

27. palkan_tula
    palkan RailsConf 2019
    # provision application
    $ dip provision
    # run web app
    $ dip rails s
    # simply launch bash within app directory
    $ dip bash
    # launch Postgres console
    $ dip psql
    BONUS: DIP
    27
    github.com/bibendi/dip
    

    View Slide

28. palkan_tula
    palkan RailsConf 2019
    BONUS: DIP
    28
    # integrate with ZSH and
    # pretend you’re not using Docker at all :)
    $ dip console | source /dev/stdin
    # that runs the command within docker container…
    $ rails c
    # …but looks like you run it locally
    $ rspec spec/test_spec.rb:23
    github.com/bibendi/dip
    

    View Slide

29. palkan_tula
    palkan RailsConf 2019
    29
    READY
    TO LAUNCH?
    $ rails c
    ???
    

    View Slide

30. palkan_tula
    palkan RailsConf 2019
    30
    $ rails c
    Traceback (most recent call last):
    60: from bin/rails:9:in `'
    // 57 lines we don’t care about
    2: from /bundle/gems/activerecord-4.2.11.1/lib/
    active_record/connection_adapters/postgresql_adapter.rb:
    651:in `connect'
    1: from /bundle/gems/activerecord-4.2.11.1/lib/
    active_record/connection_adapters/postgresql_adapter.rb:
    651:in `new'
    /bundle/gems/activerecord-4.2.11.1/lib/active_record/
    connection_adapters/postgresql_adapter.rb:651:in
    `initialize': could not connect to server: No such file or
    directory (PG ::ConnectionBad)
    
    

    View Slide

31. palkan_tula
    palkan RailsConf 2019
    31
    $ rails c
    Traceback (most recent call last):
    60: from bin/rails:9:in `'
    // 56 lines we don’t care about
    3: from /bundle/gems/aws-sdk-core-2.10.9/lib/
    seahorse/client/base.rb:83:in `after_initialize'
    2: from /bundle/gems/aws-sdk-core-2.10.9/lib/
    seahorse/client/base.rb:83:in `each'
    1: from /bundle/gems/aws-sdk-core-2.10.9/lib/
    seahorse/client/base.rb:84:in `block in after_initialize'
    /bundle/gems/aws-sdk-core-2.10.9/lib/aws-sdk-core/plugins/
    regional_endpoint.rb:34:in `after_initialize': missing
    region; use :region option or export region name to
    ENV['AWS_REGION'] (Aws ::Errors ::MissingRegionError)
    
    

    View Slide

32. palkan_tula
    palkan RailsConf 2019
    32
    WHY WE FAILED
    “The only host is
    localhost”
    Magic ENV
    Unexpected external
    deps
    Tha’s OK; Falcon 9 also failed
    

    View Slide

33. CONFIGURATION
    

    View Slide

34. palkan_tula
    palkan RailsConf 2019
    CONFIGURATION
    34
    Provide sensible defaults
    Minimize the number of external deps
    Organize configuration
    

    View Slide

35. palkan_tula
    palkan RailsConf 2019
    SENSIBLE DEFAULTS
    35
    

    View Slide

36. palkan_tula
    palkan RailsConf 2019
    Every required change could lead to
    “plz, help me” message in your Slack
    36
    

    View Slide

37. palkan_tula
    palkan RailsConf 2019
    SENSIBLE DEFAULTS
    37
    # database.yml
    default: &default
    url:
    # cable.yml
    default: &default
    adapter: redis
    url:
    # docker-compose.yml
    services:
    app: &app
    environment:
    - REDIS_URL=redis: //redis:6379/
    - DATABASE_URL=postgres: //postgres:postgres@postgres:5432
    

    View Slide

38. palkan_tula
    palkan RailsConf 2019
    OPTIONAL DEPS
    38
    # config/application.rb
    # Store uploaded files on the local file system
    # (unless AWS S3 is configured)
    config.active_storage.service =
    if AWSConfig.storage_configured?
    $stdout.puts "Using :amazon service for Active Storage"
    :amazon
    else
    :local
    end
    

    View Slide

39. palkan_tula
    palkan RailsConf 2019
    OPTIONAL SERVICES
    39
    class TwilioNotifyClient
    def initialize(sid:)
    if sid.nil?
    @noop = true
    warn "Twilio Notify client initialized in the no-op mode.\n” \
    "See docs/twilio.md on how to configure it in development"
    return
    end
    end
    def send_notification(*args)
    return if noop?
    # ...
    end
    end
    TwilioNotifyClient.new(sid: ENV["TWILIO_NOTIFY_SID"])
    

    View Slide

40. palkan_tula
    palkan RailsConf 2019
    CONFIGURATION
    40
    Provide sensible defaults
    Minimize the number of external deps
    Organize configuration
    

    View Slide

41. palkan_tula
    palkan RailsConf 2019
    ENV HELL
    41
    ENV across all over the codebase
    Rails.env.smth? checks
    

    View Slide

42. palkan_tula
    palkan RailsConf 2019
    ENV HELL
    42
    Limit ENV usage to config/environments/
    .rb
    Replace Rails.env.smth? with custom
    configuration settings
    

    View Slide

43. palkan_tula
    palkan RailsConf 2019
    43
    # config/application.rb
    config.graphiql_enabled = false
    # config/development.rb
    config.graphiql_enabled = true
    # routes.rb
    - if Rails.env.development?
    + if Rails.application.config.graphiql_enabled
    mount Graphiql ::Rack.new, at: "/graphiql"
    end
    ENV HELL
    

    View Slide

44. palkan_tula
    palkan RailsConf 2019
    LINT/ENV
    44
    bit.ly/lint-env-cop
    

    View Slide

45. palkan_tula
    palkan RailsConf 2019
    ENV HELL
    45
    ENV across all over the codebase
    Rails.env.smth? checks
    .env with dozens of entries (and .env.sample
    is out-of-date)
    

    View Slide

46. palkan_tula
    palkan RailsConf 2019
    ENV HELL
    46
    

    View Slide

47. palkan_tula
    palkan RailsConf 2019
    ENV HELL
    47
    
    

    View Slide

48. palkan_tula
    palkan RailsConf 2019
    HEROKU HELL
    48
    $ heroku config -a legacy-project | wc -l
    131
    

    View Slide

49. NEW WORLD?
    

    View Slide

50. palkan_tula
    palkan RailsConf 2019
    KEEPING CONFIGS
    50
    Store sensitive information in Rails Credentials
    (or similar)
    Keep non-sensitive information in named YAML
    files
    Allow overriding via ENV
    

    View Slide

51. palkan_tula
    palkan RailsConf 2019
    RAILS 6 CREDENTIALS
    51
    

    View Slide

52. palkan_tula
    palkan RailsConf 2019
    KEEPING CONFIGS
    52
    github.com/palkan/anyway_config
    

    View Slide

53. palkan_tula
    palkan RailsConf 2019
    KEEPING CONFIGS
    53
    github.com/palkan/anyway_config
    

    View Slide

54. palkan_tula
    palkan RailsConf 2019
    54
    PHASE #1
    * We’re on Mars!
    MARS LANDING
    ✅ Repeatable dev
    env setup
    ✅ Transparent and
    zero-“changeme”
    configuration
    

    View Slide

55. palkan_tula
    palkan RailsConf 2019
    55
    BREATHABLE
    ATMOSPHERE
    Raising tests
    reliability level
    PHASE #2
    

    View Slide

56. palkan_tula
    palkan RailsConf 2019
    TESTS ~ OXYGEN
    56
    Developing without tests is like breathing with
    no air
    Developing with slow tests is like breathing on
    the top of mt. Jomolungma
    Developing with unreliable (flaky) tests is like
    breathing in Chelyabinsk
    

    View Slide

57. CHELYABINSK
    

    View Slide

58. CHELYABINSK
    

    View Slide

59. palkan_tula
    palkan RailsConf 2019
    59
    GOAL
    PHASE #2
    “Tests should be reliable
    and fast to not block
    the development”
    * Make oxygen level at least 21% to 2065!
    

    View Slide

60. palkan_tula
    palkan RailsConf 2019
    BREATHABLE TESTS
    60
    Improve test suite speed
    

    View Slide

61. RAISE YOUR HAND
    IF YOUR TESTS ARE SLOW
    

    View Slide

62. palkan_tula
    palkan RailsConf 2019
    github.com/palkan/test-prof
    TestProf
    62
    test-prof.evilmartians.io
    

    View Slide

63. palkan_tula
    palkan RailsConf 2019
    TestProf
    63
    Tests specific profilers
    RSpec / Minitest extensions to speed up tests
    with as little refactoring as possible
    Custom Rubocop cops
    

    View Slide

64. palkan_tula
    palkan RailsConf 2019
    64
    3700 tests / 22 minutes = 170 TPM
    9800 tests / 14 minutes = 700 TPM
    4x faster!
    TestProf
    Born in “production”
    

    View Slide

65. palkan_tula
    palkan RailsConf 2019
    HOW DID WE GET THERE?
    65
    

    View Slide

66. palkan_tula
    palkan RailsConf 2019
    99 PROBLEMS OF SLOW TESTS
    66
    bit.ly/test-prof-paris
    

    View Slide

67. palkan_tula
    palkan RailsConf 2019
    FASTER TESTS: HIGHLIGHTS
    67
    Get rid of database_cleaner
    

    View Slide

68. palkan_tula
    palkan RailsConf 2019
    RAILS 5.1
    68
    github.com/rails/rails/pull/28083
    

    View Slide

69. palkan_tula
    palkan RailsConf 2019
    ActiveRecordSharedConnection
    69
    test-prof.evilmartians.io/#/active_record_shared_connection
    # Rails 5.1+
    # connection is shared out-of-the-box
    # Rails <5.1
    require “test_prof/recipes/active_record_one_love"
    

    View Slide

70. palkan_tula
    palkan RailsConf 2019
    FASTER TESTS: HIGHLIGHTS
    70
    Get rid of database_cleaner
    Do not inline background jobs by default
    

    View Slide

71. palkan_tula
    palkan RailsConf 2019
    SIDEKIQ SHAME
    71
    gist.github.com/nateberkopec/3932fce995c9feddd411417fc9bf33bf
    

    View Slide

72. palkan_tula
    palkan RailsConf 2019
    SIDEKIQ SHAME
    72
    shared_context "sq:inline" do
    around(:each) do |ex|
    Sidekiq ::Testing.inline!(&ex)
    end
    end
    RSpec.configure do |config|
    config.include_context "sq:inline", sidekiq: :inline
    end
    

    View Slide

73. palkan_tula
    palkan RailsConf 2019
    SIDEKIQ SHAME
    73
    evl.ms/blog
    

    View Slide

74. palkan_tula
    palkan RailsConf 2019
    FASTER TESTS: HIGHLIGHTS
    74
    You (likely) don’t need database_cleaner
    Do not inline background jobs by default
    Take care of your factories
    

    View Slide

75. palkan_tula
    palkan RailsConf 2019
    FACTORY CASCADE
    75
    factory :comment do
    answer
    author
    end
    factory :answer do
    question
    author
    end
    factory :question do
    author
    end
    create(:comment) # => creates 5 records
    

    View Slide

76. palkan_tula
    palkan RailsConf 2019
    FACTORY THERAPY
    76
    evl.ms/blog
    

    View Slide

77. palkan_tula
    palkan RailsConf 2019
    FASTER TESTS: HIGHLIGHTS
    77
    You (likely) don’t need database_cleaner
    Do not inline background jobs by default
    Take care of your factories
    …more
    

    View Slide

78. palkan_tula
    palkan RailsConf 2019
    test-prof.evilmartians.io
    78
    

    View Slide

79. palkan_tula
    palkan RailsConf 2019
    79
    Improve test suite speed
    Remove/reduce flakiness
    BREATHABLE TESTS
    

    View Slide

80. palkan_tula
    palkan RailsConf 2019
    FIXING FLAKY TESTS
    80
    

    View Slide

81. palkan_tula
    palkan RailsConf 2019
    81
    FIGHTING THE FLAKINESS
    bit.ly/flaky-fight
    

    View Slide

82. palkan_tula
    palkan RailsConf 2019
    FACTORY LINTER
    82
    // Check factory definitions
    $ bundle exec rake factory_lint
    Factory lint detected the following errors:
    - :city should use a sequence for :name attribute, 'cause it has a
    uniqueness constraint
    bit.ly/factory-lint
    

    View Slide

83. palkan_tula
    palkan RailsConf 2019
    FACTORY LINTER
    83
    # city.rb
    FactoryBot.define do
    factory :city do
    - name { Faker ::Address.city }
    + sequence(:name) { |n| Faker ::Address.city + " ( #{n})" }
    end
    end
    bit.ly/factory-lint
    

    View Slide

84. palkan_tula
    palkan RailsConf 2019
    84
    PHASE #2
    BREATHABLE
    ATMOSPHERE
    ✅ Tests do not block
    the development
    

    View Slide

85. binding.cat
    

    View Slide

86. palkan_tula
    palkan RailsConf 2019
    86
    TURN ICE
    INTO WATER
    Bring project back to
    the healthy state
    PHASE #3
    * Korolev crater
    

    View Slide

87. palkan_tula
    palkan RailsConf 2019
    87
    GOAL
    PHASE #3
    “Project shouldn’t have
    significant security,
    consistency and
    performance issues“
    

    View Slide

88. palkan_tula
    palkan RailsConf 2019
    SECURITY
    88
    Check dependencies (bundler-audit)
    

    View Slide

89. palkan_tula
    palkan RailsConf 2019
    bundler-audit
    89
    $ bundle audit update && bundle audit check
    Name: nokogiri
    Version: 1.8.5
    Advisory: CVE-2019-11068
    Criticality: Unknown
    URL: https: //github.com/sparklemotion/nokogiri/issues/1892
    Title: Nokogiri gem, via libxslt, is affected by improper access control
    vulnerability
    Solution: upgrade to >= 1.10.3
    Vulnerabilities found!
    github.com/rubysec/bundler-audit
    

    View Slide

90. palkan_tula
    palkan RailsConf 2019
    SECURITY
    90
    Check dependencies (bundler-audit)
    Check application code (brakeman, rubocop)
    

    View Slide

91. palkan_tula
    palkan RailsConf 2019
    BRAKEMAN
    91
    brakemanscanner.org
    

    View Slide

92. palkan_tula
    palkan RailsConf 2019
    RUBOCOP SECURITY
    92
    // Check potentially insecure code
    $ bundle exec rubocop --only Security
    Offenses:
    script.rb:33:21: C: Security/JSONLoad: Prefer JSON.parse over JSON.load.
    data = JSON.load(input.meta)
    ^^^^
    

    View Slide

93. palkan_tula
    palkan RailsConf 2019
    CONSISTENCY
    93
    Models vs. DB
    user.update!(params.require(:user).permit(:name))
    => PG ::StringDataRightTruncation: ERROR: value too long for
    type character varying(255)
    
    

    View Slide

94. palkan_tula
    palkan RailsConf 2019
    database_consistency
    94
    github.com/djezzl/database_consistency
    

    View Slide

95. palkan_tula
    palkan RailsConf 2019
    95
    class Topic < ActiveRecord ::Base
    validates :description, presence: true
    end
    $ bundle exec database_consistency
    // description column is missing `null: false` constraint
    fail Topic description column should be required in the database
    database_consistency
    github.com/djezzl/database_consistency
    

    View Slide

96. palkan_tula
    palkan RailsConf 2019
    database_validations
    96
    github.com/toptal/database_validations
    class Home < ActiveRecord ::Base
    # checks that a foreign key present
    db_belongs_to :city
    # checks that a unique index is present
    validates_db_uniqueness_of :name, case_sensitive: false
    end
    

    View Slide

97. palkan_tula
    palkan RailsConf 2019
    CONSISTENCY
    97
    Models vs. DB
    Code style?
    

    View Slide

98. palkan_tula
    palkan RailsConf 2019
    RUBOCOP
    98
    Strict config
    

    View Slide

99. palkan_tula
    palkan RailsConf 2019
    .rubocop_strict.yml
    99
    AllCops:
    DisabledByDefault: true
    Security:
    Enabled: true
    Lint/Debugger:
    Enabled: true
    Lint/Syntax:
    Enabled: true
    Lint/Env:
    Enabled: true
    RSpec/Focus:
    Enabled: true
    

    View Slide

100. palkan_tula
     palkan RailsConf 2019
     .rubocop_strict.yml
     100
     AllCops:
     DisabledByDefault: true
     Security:
     Enabled: true
     Lint/Debugger:
     Enabled: true
     Lint/Syntax:
     Enabled: true
     Lint/Env:
     Enabled: true
     RSpec/Focus:
     Enabled: true
     

     View Slide

101. palkan_tula
     palkan RailsConf 2019
     .rubocop_strict.yml
     101
     AllCops:
     DisabledByDefault: true
     Security:
     Enabled: true
     Lint/Debugger:
     Enabled: true
     Lint/Syntax:
     Enabled: true
     Lint/Env:
     Enabled: true
     RSpec/Focus:
     Enabled: true
     

     View Slide

102. palkan_tula
     palkan RailsConf 2019
     .rubocop_strict.yml
     102
     AllCops:
     DisabledByDefault: true
     Security:
     Enabled: true
     Lint/Debugger:
     Enabled: true
     Lint/Syntax:
     Enabled: true
     Lint/Env:
     Enabled: true
     RSpec/Focus:
     Enabled: true
     

     View Slide

103. palkan_tula
     palkan RailsConf 2019
     .rubocop_strict.yml
     103
     AllCops:
     DisabledByDefault: true
     Security:
     Enabled: true
     Lint/Debugger:
     Enabled: true
     Lint/Syntax:
     Enabled: true
     Lint/Env:
     Enabled: true
     RSpec/Focus:
     Enabled: true
     

     View Slide

104. palkan_tula
     palkan RailsConf 2019
     .rubocop_strict.yml + CI
     104
     # .circleci/config.yml
     rubocop_strict:
     executor: ruby
     steps:
     - attach_workspace:
     at: .
     - run:
     name: Strict Rubocop check
     command: |
     bundle exec rubocop -c .rubocop_strict.yml
     

     View Slide

105. palkan_tula
     palkan RailsConf 2019
     RUBOCOP
     105
     Strict config
     Progressive enhancement
     

     View Slide

106. palkan_tula
     palkan RailsConf 2019
     .rubocop.yml
     106
     require:
     - rubocop-rspec
     - standard/cop/semantic_blocks
     inherit_gem:
     standard: config/base.yml
     AllCops:
     Include:
     # explicitly specify terraformed code
     - "**/community/**/*.rb"
     Exclude:
     - "db/schema.rb"
     - "bin /*"
     

     View Slide

107. palkan_tula
     palkan RailsConf 2019
     .rubocop.yml
     107
     require:
     - rubocop-rspec
     - standard/cop/semantic_blocks
     inherit_gem:
     standard: config/base.yml
     AllCops:
     Include:
     # explicitly specify terraformed code
     - "**/community/**/*.rb"
     Exclude:
     - "db/schema.rb"
     - "bin /*"
     

     View Slide

108. palkan_tula
     palkan RailsConf 2019
     .rubocop.yml
     108
     require:
     - rubocop-rspec
     - standard/cop/semantic_blocks
     inherit_gem:
     standard: config/base.yml
     AllCops:
     Include:
     # explicitly specify terraformed code
     - "**/community/**/*.rb"
     Exclude:
     - "db/schema.rb"
     - "bin /*"
     

     View Slide

109. palkan_tula
     palkan RailsConf 2019
     STANDARD
     109
     github.com/testdouble/standard
     

     View Slide

110. palkan_tula
     palkan RailsConf 2019
     110
     SIDE
     EFFECTS
     

     View Slide

111. palkan_tula
     palkan RailsConf 2019
     SIDE EFFECTS
     111
     Non-atomic transactions
     class Post < ActiveRecord ::Base
     after_create :notify_author
     def notify_users
     # send email even if transaction failed
     UsersMailer.new_post(author, post.title).deliver_later
     end
     end
     

     View Slide

112. palkan_tula
     palkan RailsConf 2019
     ISOLATOR
     112
     github.com/palkan/isolator
     

     View Slide

113. palkan_tula
     palkan RailsConf 2019
     ISOLATOR
     113
     github.com/palkan/isolator
     $ bundle exec rspec
     1) Create post example
     Failure/Error: job_or_instantiate(*args).enqueue
     Isolator ::BackgroundJobError:
     You are trying to enqueue background job inside db transaction.
     Details: ActionMailer ::DeliveryJob (UsersMailer, new_post)
     

     View Slide

114. palkan_tula
     palkan RailsConf 2019
     114
     DEAD
     CODE
     

     View Slide

115. palkan_tula
     palkan RailsConf 2019
     DEAD CODE
     115
     Gems
     

     View Slide

116. palkan_tula
     palkan RailsConf 2019
     DEAD GEMS
     116
     $ GEM_TRACK=1 bundle exec rspec
     Maybe unused gems:
     activerecord-postgres_enum-0.3.0
     avatax-18.12.0
     aws-sdk-2.10.9
     rails-4.2.11.1
     gibbon-2.2.5
     bit.ly/track-gems
     

     View Slide

117. palkan_tula
     palkan RailsConf 2019
     117
     Gems
     Routes/controllers
     DEAD CODE
     

     View Slide

118. palkan_tula
     palkan RailsConf 2019
     traceroute
     118
     github.com/amatsuda/traceroute
     $ bundle exec rake traceroute
     Unused routes (3):
     users#create
     users#new
     catalog#purchase
     Unreachable action methods (1):
     users#index2
     

     View Slide

119. palkan_tula
     palkan RailsConf 2019
     119
     Gems
     Routes/controllers
     Views
     DEAD CODE
     

     View Slide

120. palkan_tula
     palkan RailsConf 2019
     TEMPLATES TRACKER
     120
     $ TT=1 bundle exec rspec
     ======== Unused Templates =========
     /app/app/views/home/index.html.erb
     /app/app/views/housekeeping/scheduling/index.html.erb
     bit.ly/track-templates
     

     View Slide

121. palkan_tula
     palkan RailsConf 2019
     121
     Gems
     Routes/controllers
     Views
     Factories NEW!
     DEAD CODE
     

     View Slide

122. palkan_tula
     palkan RailsConf 2019
     FACTORY TRACE
     122
     $ FB_TRACE=1 bundle exec rspec
     total number of unique used factories & traits: 1
     total number of unique unused factories & traits: 3
     unused trait 'with_phone' of factory 'user'
     unused factory 'special_user'
     unused global trait 'with_email'
     github.com/djezzzl/factory_trace
     

     View Slide

123. palkan_tula
     palkan RailsConf 2019
     123
     TURN ICE
     INTO WATER
     PHASE #3
     ✅ Project is healthy
     enough to bring more
     people
     

     View Slide

124. palkan_tula
     palkan RailsConf 2019
     124
     ROBOTS
     Automating things
     BONUS
     

     View Slide

125. palkan_tula
     palkan RailsConf 2019
     LEFT HOOK
     125
     github.com/Arkweid/lefthook
     $ git commit -m "chore: use lefthook"
     RUNNING HOOKS GROUP: pre-commit
     EXECUTE > rubocop
     1 file inspected, 1 offense detected
     rubocop
     

     View Slide

126. palkan_tula
     palkan RailsConf 2019
     LEFT HOOK
     126
     github.com/Arkweid/lefthook
     $ git commit -m "chore: use lefthook"
     RUNNING HOOKS GROUP: pre-commit
     EXECUTE > rubocop
     1 file inspected, no offenses detected
     ✅ rubocop
     RUNNING HOOKS GROUP: prepare-commit-msg
     EXECUTE > jira_link.rb
     JIRA ticket ID (type 'N/n' to skip): 2019
     ✅ jira_link.rb
     

     View Slide

127. palkan_tula
     palkan RailsConf 2019
     DANGER
     127
     danger.systems
     

     View Slide

128. palkan_tula
     palkan RailsConf 2019
     FINAL
     SCORING
     128
     

     View Slide

129. palkan_tula
     palkan RailsConf 2019
     github.com/evilmartians/terraforming-rails
     DO IT YOURSELF
     129
     

     View Slide

130. palkan_tula
     palkan RailsConf 2019
     …OR NOT
     130
     evilmartians.com
     

     View Slide

131. COMING SOON
     

     View Slide

132. SPECIAL THANKS
     2061.su
     

     View Slide

133. palkan_tula
     palkan RailsConf 2019
     133
     THANK YOU!
     Vladimir Dementyev
     evilmartians.com
     @evilmartians
     

     View Slide