Dr Sheldon Cooper Presents: Fun with Flags

No no, not country flags, feature flags! Feature flags are a powerful technique that allows teams to modify a system’s behaviour without changing code. They can be used several reasons – canary releases and A/B testing to name a few.

This talk will show you how you’re already using feature flags in your application without realising it. Next, we’ll take a look at some of the best tooling out there to help you take feature flags to the next level. Finally, we’ll cover strategies for removing feature flags before they become technical debt that you have to manage.

Transcript

2. Michael Heap
9. Fun with Country Flags! Presented by @mheap at @phpday
10. Fun with Country Flags! Presented by @mheap at @phpday
11. Fun with Country Flags! Presented by @mheap at @phpday
12. Fun with Country Flags! Presented by @mheap at @phpday
13. Fun with Feature Flags! Presented by @mheap at @phpday
14. Michael @mheap Developer Relations NexmoDev
15. Fun with Feature Flags! Presented by @mheap at @phpday
16. Today’s Plan
17. 1. What are feature flags? 2. Implementation 3. Flag management 4. Tips and tricks 5. Conclusion
18. 1. What are feature flags? 2. Implementation 3. Flag management 4. Tips and tricks 5. Conclusion
19. 1. What are feature flags? 2. Implementation 3. Flag management 4. Tips and tricks 5. Conclusion
20. 1. What are feature flags? 2. Implementation 3. Flag management 4. Tips and tricks 5. Conclusion
21. 1. What are feature flags? 2. Implementation 3. Flag management 4. Tips and tricks 5. Conclusion
22. Feature Flags?
23. Feature Toggles?
24. Feature Flip?
25. Feature Gate?
26. Feature Switches?
27. Separates feature release from code deployment
28. http://code.flickr.net/2009/12/02/flipping-out/
31. Feature flags aren’t new
32. #ifdef IBM_ANALYSIS IBM_ANALYSIS(audio) #else INTERNAL_ANALYSIS(audio) #endif $ make build -DIBM_ANALYSIS
33. ./make_call.sh —-use-internal-analysis ./make_call.sh —-use-ibm-analysis
34. if (in_array($user->id, $whitelistedUsers)) { return $ibm->analyzeAudio($audio); } return $sentiment->analyze($audio);
35. Use Cases?
36. 1. Permissions
37. 1. Permissions 2. Early-access
38. 1. Permissions 2. Early-access 3. Opt-in
39. 1. Permissions 2. Early-access 3. Opt-in 4. Incremental roll-out
40. 1. Permissions 2. Early-access 3. Opt-in 4. Incremental roll-out 5. Block users
41. 1. Permissions 2. Early-access 3. Opt-in 4. Incremental roll-out 5. Block users 6. Calendar driven
42. 1. Permissions 2. Early-access 3. Opt-in 4. Incremental roll-out 5. Block users 6. Calendar driven 7. Kill switch
43. 1. Permissions 2. Early-access 3. Opt-in 4. Incremental roll-out 5. Block users 6. Calendar driven 7. Kill switch 8. Power user
44. 1. Permissions 2. Early-access 3. Opt-in 4. Incremental roll-out 5. Block users 6. Calendar driven 7. Kill switch 8. Power user 9. Maintenance
45. 1. Permissions 2. Early-access 3. Opt-in 4. Incremental roll-out 5. Block users 6. Calendar driven 7. Kill switch 8. Power user 9. Maintenance 10. Sunset
46. Flag Classes
47. Ops Toggles Release Toggles Flag Classes Permission Toggles Experiment Toggles
48. Release Toggles Ops Toggles Flag Classes Permission Toggles Experiment Toggles Lifetime Days Dynamism Per deployment
49. Release Toggles Ops Toggles Flag Classes Permission Toggles Experiment Toggles Lifetime Days - Weeks Dynamism Human Controlled
50. Release Toggles Ops Toggles Flag Classes Permission Toggles Experiment Toggles Lifetime Years Dynamism Per Request
51. Release Toggles Ops Toggles Flag Classes Permission Toggles Experiment Toggles Lifetime Weeks - Months Dynamism Per Request
52. https://martinfowler.com/articles/feature-toggles.html
53. Ownership Release toggles owned by devs Ops toggles owned by ops Permission toggles Experiment toggles owned by product
54. Flag Scopes
55. On/Off Switch Enable or disable entirely
56. On/Off Switch Percentage of users Enable or disable entirely Toggle for a percentage of users
57. On/Off Switch Percentage of users Individuals Enable or disable entirely Toggle for a percentage of users Toggle for specific users
58. On/Off Switch Percentage of users Individuals Groups Enable or disable entirely Toggle for a percentage of users Toggle for specific users Enable for specific groups e.g. Power Users
59. On/Off Switch Percentage of users Individuals Groups Request information Enable or disable entirely Toggle for a percentage of users Toggle for specific users Enable for specific groups e.g. Power Users Enable for specific request headers or bodies
60. Implementation
61. Build vs Buy
62. 1. Dashboard
63. 1. Dashboard 2. Access control
64. 1. Dashboard 2. Access control 3. Complex rules
65. 1. Dashboard 2. Access control 3. Complex rules 4. Cascading flags
66. 1. Dashboard 2. Access control 3. Complex rules 4. Cascading flags 5. Multivariate rules
67. 1. Dashboard 2. Access control 3. Complex rules 4. Cascading flags 5. Multivariate rules 6. Auditing
68. 1. Dashboard 2. Access control 3. Complex rules 4. Cascading flags 5. Multivariate rules 6. Auditing 7. Speed
69. 1. Dashboard 2. Access control 3. Complex rules 4. Cascading flags 5. Multivariate rules 6. Auditing 7. Speed 8. Scale
70. 1. Dashboard 2. Access control 3. Complex rules 4. Cascading flags 5. Multivariate rules 6. Auditing 7. Speed 8. Scale 9. 100% uptime
71. Build
72. Rollout (Ruby) # Is a feature active? $rollout.active?(:chat) # Activate a specific user $rollout.activate_user(:chat, @user) # Define a group $rollout.define_group(:admins) do |user| user.admin? end # Roll out to a percentage of users $rollout.activate_percentage(:chat, 20)
73. Rollout (PHP) # Is a feature active? $rollout->isActive('chat'); # Activate a specific user $rollout->activateUser('chat', $user); # Define a group $rollout->defineGroup('admins', function($user = null) { return $user->isAdmin(); }); # Roll out to a percentage of users $rollout->activatePercentage('chat', 20);
74. Qandidate Toggle $manager = new ToggleManager(new InMemoryCollection()); $afterSix = new GreaterThanEqual(18); $beforeTen = new LessThanEqual(22); $conditions = []; $conditions[] = new OperatorCondition('time', $afterSix); $conditions[] = new OperatorCondition('time', $beforeTen); $toggle = new Toggle('disable-work-email', $conditions, Toggle::STRATEGY_UNANIMOUS); $manager->add($toggle); $context = new Context(); $context->set('time', (int) date('G')); echo 'Everyone is ' . ($manager->active(‘disable-work-email', $context)) ? ‘happy!' : 'sad :(';
75. Qandidate Toggle $manager = new ToggleManager(new InMemoryCollection()); $afterSix = new GreaterThanEqual(18); $beforeTen = new LessThanEqual(22); $conditions = []; $conditions[] = new OperatorCondition('time', $afterSix); $conditions[] = new OperatorCondition('time', $beforeTen); $toggle = new Toggle('disable-work-email', $conditions, Toggle::STRATEGY_UNANIMOUS); $manager->add($toggle); $context = new Context(); $context->set('time', (int) date('G')); echo 'Everyone is ' . ($manager->active(‘disable-work-email', $context)) ? ‘happy!' : 'sad :(';
76. Qandidate Toggle $manager = new ToggleManager(new InMemoryCollection()); $afterSix = new GreaterThanEqual(18); $beforeTen = new LessThanEqual(22); $conditions = []; $conditions[] = new OperatorCondition('time', $afterSix); $conditions[] = new OperatorCondition('time', $beforeTen); $toggle = new Toggle('disable-work-email', $conditions, Toggle::STRATEGY_UNANIMOUS); $manager->add($toggle); $context = new Context(); $context->set('time', (int) date('G')); echo 'Everyone is ' . ($manager->active('disable-work-email', $context)) ? ‘happy!' : 'sad :(';
77. Qandidate Toggle $manager = new ToggleManager(new InMemoryCollection()); $afterSix = new GreaterThanEqual(18); $beforeTen = new LessThanEqual(22); $conditions = []; $conditions[] = new OperatorCondition('time', $afterSix); $conditions[] = new OperatorCondition('time', $beforeTen); $toggle = new Toggle('disable-work-email', $conditions, Toggle::STRATEGY_UNANIMOUS); $manager->add($toggle); $context = new Context(); $context->set('time', (int) date('G')); echo 'Everyone is ' . ($manager->active('disable-work-email', $context)) ? ‘happy!' : 'sad :(';
78. Qandidate Toggle $manager = new ToggleManager(new InMemoryCollection()); $afterSix = new GreaterThanEqual(18); $beforeTen = new LessThanEqual(22); $conditions = []; $conditions[] = new OperatorCondition('time', $afterSix); $conditions[] = new OperatorCondition('time', $beforeTen); $toggle = new Toggle('disable-work-email', $conditions, Toggle::STRATEGY_UNANIMOUS); $manager->add($toggle); $context = new Context(); $context->set('time', (int) date('G')); echo 'Everyone is ' . ($manager->active('disable-work-email', $context)) ? ‘happy!' : 'sad :(';
79. Qandidate Toggle $manager = new ToggleManager(new InMemoryCollection()); $afterSix = new GreaterThanEqual(18); $beforeTen = new LessThanEqual(22); $conditions = []; $conditions[] = new OperatorCondition('time', $afterSix); $conditions[] = new OperatorCondition('time', $beforeTen); $toggle = new Toggle('disable-work-email', $conditions, Toggle::STRATEGY_AFFIRMATIVE); $manager->add($toggle); $context = new Context(); $context->set('time', (int) date('G')); echo 'Everyone is ' . ($manager->active('disable-work-email', $context)) ? ‘happy!' : 'sad :(';
80. Qandidate Toggle $manager = new ToggleManager(new InMemoryCollection()); $afterSix = new GreaterThanEqual(18); $beforeTen = new LessThanEqual(22); $conditions = []; $conditions[] = new OperatorCondition('time', $afterSix); $conditions[] = new OperatorCondition('time', $beforeTen); $toggle = new Toggle('disable-work-email', $conditions, Toggle::STRATEGY_MAJORITY); $manager->add($toggle); $context = new Context(); $context->set('time', (int) date('G')); echo 'Everyone is ' . ($manager->active('disable-work-email', $context)) ? ‘happy!' : 'sad :(';
81. Qandidate Toggle $manager = new ToggleManager(new InMemoryCollection()); $afterSix = new GreaterThanEqual(18); $beforeTen = new LessThanEqual(22); $conditions = []; $conditions[] = new OperatorCondition('time', $afterSix); $conditions[] = new OperatorCondition('time', $beforeTen); $toggle = new Toggle('disable-work-email', $conditions, Toggle::STRATEGY_AFFIRMATIVE); $manager->add($toggle); $context = new Context(); $context->set('time', (int) date('G')); echo 'Everyone is ' . ($manager->active('disable-work-email', $context)) ? ‘happy!' : 'sad :(';
82. Qandidate Toggle $manager = new ToggleManager(new InMemoryCollection()); $afterSix = new GreaterThanEqual(18); $beforeTen = new LessThanEqual(22); $conditions = []; $conditions[] = new OperatorCondition('time', $afterSix); $conditions[] = new OperatorCondition('time', $beforeTen); $toggle = new Toggle('disable-work-email', $conditions, Toggle::STRATEGY_UNANIMOUS); $manager->add($toggle); $context = new Context(); $context->set('time', (int) date('G')); echo 'Everyone is ' . ($manager->active('disable-work-email', $context)) ? ‘happy!' : 'sad :(';
83. Qandidate Toggle $manager = new ToggleManager(new InMemoryCollection()); $afterSix = new GreaterThanEqual(18); $beforeTen = new LessThanEqual(22); $conditions = []; $conditions[] = new OperatorCondition('time', $afterSix); $conditions[] = new OperatorCondition('time', $beforeTen); $toggle = new Toggle('disable-work-email', $conditions, Toggle::STRATEGY_UNANIMOUS); $manager->add($toggle); $context = new Context(); $context->set('time', (int) date('G')); echo 'Everyone is ' . ($manager->active('disable-work-email', $context)) ? ‘happy!' : 'sad :(';
84. Qandidate Toggle $manager = new ToggleManager(new InMemoryCollection()); $afterSix = new GreaterThanEqual(18); $beforeTen = new LessThanEqual(22); $conditions = []; $conditions[] = new OperatorCondition('time', $afterSix); $conditions[] = new OperatorCondition('time', $beforeTen); $toggle = new Toggle('disable-work-email', $conditions, Toggle::STRATEGY_UNANIMOUS); $manager->add($toggle); $context = new Context(); $context->set('time', (int) date('G')); echo 'Everyone is ' . ($manager->active('disable-work-email', $context)) ? ‘happy!' : 'sad :(';
85. $manager = new ToggleManager(new InMemoryCollection()); $toggle = new Toggle('some-feature', [ new OperatorCondition('user_id', new GreaterThan(41)) ]); $manager->add($toggle); Configuration: Code
86. Configuration: Array $data = array( 'some-feature' => array( 'name' => 'toggling', 'conditions' => array( array( 'name' => 'operator-condition', 'key' => 'user_id', 'operator' => array('name' => 'greater-than', 'value' => 41), ), ), ), ); $serializer = new InMemoryCollectionSerializer(); $collection = $serializer->deserialize($data); $manager = new ToggleManager($collection);
87. Configuration: JSON/YAML $yaml = <<<YML toggles: - name: some-feature conditions: - name: operator-condition key: user_id operator: name: greater-than value: 41 YML; $array = Yaml::parse($yaml); $serializer = new InMemoryCollectionSerializer(); $collection = $serializer->deserialize($array); $manager = new ToggleManager($collection);
88. Configuration: Redis $predis = new Predis\Client(); $collection = new PredisCollection('toggle_demo', $predis); $manager = new ToggleManager($collection);
89. Qandidate Toggle API { "conditions" : [ { "name" : "operator-condition", "operator" : { "name" : "less-than", "value" : "1337" }, "key" : "user_id" } ], "name" : "foo", "status" : "conditionally-active", "originalName" : "foo" } PUT /toggles/{name} https://github.com/qandidate-labs/qandidate-toggle-api
90. Qandidate Toggle UI https://github.com/qandidate-labs/qandidate-toggle-ui
91. Build (Pros) 1. Free! 2. Total control 3. Complex rules 4. API and UI available
92. Build (Cons) 1. Self hosted 2. PHP only 3. Complex rules
93. Buy
95. Multi-Language
96. Prebuilt Dashboard
97. Environment Aware
98. Scaleable
99. Audit Log
100. A/B Testing
101. Buy (Pros) 1. Lovely dashboard 2. Multi-language 3. Built in audit log 4. Environment aware 5. A/B testing conversion tracking
102. Buy (Cons) 1. It costs $79/month 2. Can’t modify the product 3. Dependent on 3rd party
103. Build vs Buy
104. It depends
105. Flag Management
106. Toggle Configuratin
107. Hard Coded Change the code Dynamic Static
108. Hard Coded Deploy Config Change the code Deploy your application Dynamic Static
109. Hard Coded Deploy Config Parameterised Config Change the code Deploy your application Edit config, restart app Dynamic Static
110. Hard Coded Deploy Config Parameterised Config Database Config Change the code Deploy your application Edit config, restart app Edit via UI Dynamic Static
111. Hard Coded Deploy Config Parameterised Config Database Config Distributed Config Change the code Deploy your application Edit config, restart app Edit via UI e.g. Consul or Zookeeper Dynamic Static
112. Feature Dashboard
113. Flag State
114. Role Based Access
115. Audit Log
116. Non-technical Users
117. Technical Debt
118. Cleanup based on activity
119. Cleanup based on activity
120. Create & Cleanup
121. WIP limits
122. WIP limits
123. Expiration date
124. Explosion date
125. Tips & Tricks
126. Testing Flags
127. Testing Flags Feature A Feature B ✅ ✅ ✅ ☠ ☠ ✅ ☠ ☠
128. Testing Flags Feature A Feature B Feature C ✅ ✅ ✅ ✅ ☠ ✅ ✅ ✅ ☠ ☠ ✅ ✅ ✅ ☠ ☠ ☠ ✅ ☠ ☠ ☠ ✅ ☠ ☠ ☠
129. Testing Flags Feature A Feature B Feature C Feature D ✅ ✅ ✅ ✅ ✅ ✅ ✅ ☠ ✅ ✅ ☠ ✅ ✅ ☠ ✅ ✅ ☠ ✅ ✅ ✅ ✅ ✅ ☠ ☠ ✅ ☠ ✅ ☠ ✅ ☠ ☠ ✅ ☠ ✅ ✅ ☠ ☠ ✅ ☠ ✅ ☠ ☠ ✅ ✅ ✅ ☠ ☠ ☠ ☠ ✅ ☠ ☠ ☠ ☠ ✅ ☠ ☠ ☠ ☠ ✅ ☠ ☠ ☠ ☠
130. Testing Flags Number of flags Possible permutations 2 4 3 8 4 16 5 32 10 1024 25 33,554,432 50 1.12589991E+15 100 1.2676506E+30
131. Homepage Carousel Homepage CTA ✅ ✅ ✅ ☠ ☠ ✅ ☠ ☠ Forum Edit Permission Forum Delete Permission ✅ ✅ ✅ ☠ ☠ ✅ ☠ ☠ Upload Profile Image ✅ ☠ New Interesting Algorithm ✅ ☠ High Post Length ✅ ☠ Show Debug Info? ✅ ☠ Enable Audit Log ✅ ☠ Auto Logout ✅ ☠ API Access API v2 ✅ ✅ ✅ ☠ ☠ ✅ ☠ ☠
132. Expose State { "api_v2": true, "audit_log": true, "new_recommendation_algo": false } GET /toggle_status
133. Flag Descriptions basic-rec-algo: true
134. Flag Descriptions basic-rec-algo: enabled: true description: Use a simplistic recommendation algorithm. This is fast and produces less load on backend systems, but is way less accurate than our standard algorithm.
135. Clear Naming allow_user_delete and allow_user_edit not user_control
136. Audit Log Feature State User Date allow_user_edit ✅ Sarah 2018-05-11 12:22:08 enhanced_rec_algo ✅ Ashley 2018-05-04 15:33:16 allow_user_signup ☠ Ashley 2018-05-04 15:27:33 enhanced_rec_algo ☠ system:load_manager 2018-05-04 15:16:30 allow_user_signup ✅ Bob 2018-05-04 15:12:01 enable_api ✅ Sarah 2018-04-30 09:56:59
137. Fail Safe Do positively enable features e.g. enable-ibm- analysis, enhanced-recomendation-algo Don’t use flags for suppressing new features e.g. disable-shiny-new-feature
138. Conclusion
139. Flags are great!
140. Ops Toggles Release Toggles Flag Classes Permission Toggles Experiment Toggles
141. Build vs Buy
142. Qandidate Toggle
144. One More Thing
145. No Reuse
146. Knight Capital
147. High frequency trader
148. Mistakes were made
149. Knight Capital 1. Reused flags
150. Knight Capital 1. Reused flags 2. Didn’t delete obsolete code
151. Knight Capital 1. Reused flags 2. Didn’t delete obsolete code 3. Couldn’t be disabled without a deployment
152. Knight Capital 1. Reused flags 2. Didn’t delete obsolete code 3. Couldn’t be disabled without a deployment 4. The deploy actually enabled the old code on all 8 servers, instead of disabling it
153. $460m Gone
154. @mheap / @NexmoDev m@michaelheap.com https://joind.in/talk/298e7