Deprecating ActiveRecord Attributes without making Zombies
1 like712 views
The document discusses strategies for removing unused attributes from ActiveRecord models in Ruby on Rails. It describes marking attributes as deprecated to prevent direct access and filter them from serialization. This avoids errors on save from missing database columns while allowing existing data to be rendered normally. The process involves marking attributes as deprecated, handling access attempts, updating serialization, and deploying after a migration removes the columns.
![API OUTPUT
-
class User
alias_method :super_serializable_hash, :serializable_hash
def serializable_hash(options = {})
options.merge! {
:only => self.attributes.keys.map(&:to_sym) -
(self.class.deprecated_attributes ||
[]).map(&:to_sym)
}
super_serializable_hash(options)
end
end
Friday, May 10, 13](https://image.slidesharecdn.com/zombiesattributes-130510014524-phpapp01/85/Deprecating-ActiveRecord-Attributes-without-making-Zombies-24-320.jpg)
![API OUTPUT
-
class User
alias_method :super_serializable_hash, :serializable_hash
def serializable_hash(options = {})
options.merge! {
:only => self.attributes.keys.map(&:to_sym) -
(self.class.deprecated_attributes ||
[]).map(&:to_sym)
}
super_serializable_hash(options)
end
end
Friday, May 10, 13](https://image.slidesharecdn.com/zombiesattributes-130510014524-phpapp01/85/Deprecating-ActiveRecord-Attributes-without-making-Zombies-25-320.jpg)
![API OUTPUT
-
class User
alias_method :super_serializable_hash, :serializable_hash
def serializable_hash(options = {})
options.merge! {
:only => self.attributes.keys.map(&:to_sym) -
(self.class.deprecated_attributes ||
[]).map(&:to_sym)
}
super_serializable_hash(options)
end
end
Friday, May 10, 13](https://image.slidesharecdn.com/zombiesattributes-130510014524-phpapp01/85/Deprecating-ActiveRecord-Attributes-without-making-Zombies-26-320.jpg)
![API OUTPUT
-
class User
alias_method :super_serializable_hash, :serializable_hash
def serializable_hash(options = {})
options.merge! {
:only => self.attributes.keys.map(&:to_sym) -
(self.class.deprecated_attributes ||
[]).map(&:to_sym)
}
super_serializable_hash(options)
end
end
Friday, May 10, 13](https://image.slidesharecdn.com/zombiesattributes-130510014524-phpapp01/85/Deprecating-ActiveRecord-Attributes-without-making-Zombies-27-320.jpg)
![ACCESSORS =
[ '',
'=',
'_before_type_cast',
'?',
'_changed?',
'_change',
'_will_change!',
'_was']
Zombie Radar
-
FIELD HUNTING
Friday, May 10, 13](https://image.slidesharecdn.com/zombiesattributes-130510014524-phpapp01/85/Deprecating-ActiveRecord-Attributes-without-making-Zombies-28-320.jpg)
![IGNORE COLUMNS
-
class User
def columns
self.class.columns.reject do |c|
(self.class.deprecated_attributes || []).include? c.name.to_s
end
end
end
Friday, May 10, 13](https://image.slidesharecdn.com/zombiesattributes-130510014524-phpapp01/85/Deprecating-ActiveRecord-Attributes-without-making-Zombies-49-320.jpg)
Deprecating ActiveRecord Attributes without making Zombies
- 1. - Friday, May 10, 13
- 2. YANN ARMAND - @yarmand Friday, May 10, 13
- 3. - The Enterprise Social Network Friday, May 10, 13
- 4. Friday, May 10, 13
- 5. DELETE A DB COLUMN WITHOUT MAKING ZOMBIES Friday, May 10, 13
- 6. DELETE A DB COLUMN WITHOUT MAKING ZOMBIES Friday, May 10, 13
- 7. WHY DELETE A MODEL ATTRIBUTE ? - Friday, May 10, 13
- 8. WHY DELETE A MODEL ATTRIBUTE ? • Not used anymore - Friday, May 10, 13
- 9. WHY DELETE A MODEL ATTRIBUTE ? • Not used anymore User Payment card • card_type • card_number • Move to another model - Friday, May 10, 13
- 10. KILLING AN ACTIVE RECORD FIELD Cons - Friday, May 10, 13
- 11. KILLING AN ACTIVE RECORD FIELD • Code dependency Cons - Friday, May 10, 13
- 12. KILLING AN ACTIVE RECORD FIELD • Code dependency Cons • Unknown impact on the app behavior - Friday, May 10, 13
- 13. KILLING AN ACTIVE RECORD FIELD • Code dependency Cons • Unknown impact on the app behavior - Friday, May 10, 13
- 14. KILLING AN ACTIVE RECORD FIELD • Code dependency Cons • Unknown impact on the app behavior - Friday, May 10, 13
- 15. KILL AN ACTIVE RECORD FIELD Pros - Friday, May 10, 13
- 16. KILL AN ACTIVE RECORD FIELD Pros • ReduceTechnical Debt - Friday, May 10, 13
- 17. KILL AN ACTIVE RECORD FIELD Pros • ReduceTechnical Debt • Smaller code base • Lower barrier of entry - • Eliminate black holes • Prevent crashes Friday, May 10, 13
- 18. BE PREPARED !! - Friday, May 10, 13
- 19. BE PREPARED !! - Friday, May 10, 13
- 20. BE PREPARED !! - Friday, May 10, 13
- 21. class User deprecate_attribute :card_type deprecate_attribute :card_number end - Friday, May 10, 13
- 22. API OUTPUT render :json => user name: 'roger' age: 23 card_type: 'visa' card_number: 123412341234 name: 'roger' age: 23 - Friday, May 10, 13
- 23. API OUTPUT render :json => user name: 'roger' age: 23 card_type: 'visa' card_number: 123412341234 name: 'roger' age: 23 - ActiveRecord#serializable_hash Friday, May 10, 13
- 24. API OUTPUT - class User alias_method :super_serializable_hash, :serializable_hash def serializable_hash(options = {}) options.merge! { :only => self.attributes.keys.map(&:to_sym) - (self.class.deprecated_attributes || []).map(&:to_sym) } super_serializable_hash(options) end end Friday, May 10, 13
- 25. API OUTPUT - class User alias_method :super_serializable_hash, :serializable_hash def serializable_hash(options = {}) options.merge! { :only => self.attributes.keys.map(&:to_sym) - (self.class.deprecated_attributes || []).map(&:to_sym) } super_serializable_hash(options) end end Friday, May 10, 13
- 26. API OUTPUT - class User alias_method :super_serializable_hash, :serializable_hash def serializable_hash(options = {}) options.merge! { :only => self.attributes.keys.map(&:to_sym) - (self.class.deprecated_attributes || []).map(&:to_sym) } super_serializable_hash(options) end end Friday, May 10, 13
- 27. API OUTPUT - class User alias_method :super_serializable_hash, :serializable_hash def serializable_hash(options = {}) options.merge! { :only => self.attributes.keys.map(&:to_sym) - (self.class.deprecated_attributes || []).map(&:to_sym) } super_serializable_hash(options) end end Friday, May 10, 13
- 28. ACCESSORS = [ '', '=', '_before_type_cast', '?', '_changed?', '_change', '_will_change!', '_was'] Zombie Radar - FIELD HUNTING Friday, May 10, 13
- 29. - def deprecate_attribute attr msg = "You can't access atribute #{attr}, it has been deprecated" ACCESSORS.each do |term| define_method("#{attr}#{term}") do |*args| raise DeprecatedAttributeError, msg super end end end Friday, May 10, 13
- 30. - def deprecate_attribute attr msg = "You can't access atribute #{attr}, it has been deprecated" ACCESSORS.each do |term| define_method("#{attr}#{term}") do |*args| raise DeprecatedAttributeError, msg super end end end Friday, May 10, 13
- 31. - def deprecate_attribute attr msg = "You can't access atribute #{attr}, it has been deprecated" ACCESSORS.each do |term| define_method("#{attr}#{term}") do |*args| raise DeprecatedAttributeError, msg super end end end Friday, May 10, 13
- 32. - def deprecate_attribute attr msg = "You can't access atribute #{attr}, it has been deprecated" ACCESSORS.each do |term| define_method("#{attr}#{term}") do |*args| raise DeprecatedAttributeError, msg super end end end Friday, May 10, 13
- 33. - def deprecate_attribute attr msg = "You can't access atribute #{attr}, it has been deprecated" ACCESSORS.each do |term| define_method("#{attr}#{term}") do |*args| raise DeprecatedAttributeError, msg super end end end Friday, May 10, 13
- 34. - def deprecate_attribute attr msg = "You can't access atribute #{attr}, it has been deprecated" ACCESSORS.each do |term| define_method("#{attr}#{term}") do |*args| raise DeprecatedAttributeError, msg super end end end Friday, May 10, 13
- 35. Friday, May 10, 13
- 36. class ApplicationController rescue_from DeprecatedAttributeError, :with => :log_deprecate private def log_deprecated e deprecated_logger.error(e.backtrace.join("n")) e.continue end end Friday, May 10, 13
- 37. cmaruz/continuable class ApplicationController rescue_from DeprecatedAttributeError, :with => :log_deprecate private def log_deprecated e deprecated_logger.error(e.backtrace.join("n")) e.continue end end Friday, May 10, 13
- 38. REFACTOR - Friday, May 10, 13
- 40. REFACTOR New Code - DEPLOY Friday, May 10, 13
- 43. WHAT HAPPENS ? name: 'roger' age: 23 card_type: 'visa' card_number: 123412341234 - Time In Cache Friday, May 10, 13
- 44. WHAT HAPPENS ? name: 'roger' age: 23 card_type: 'visa' card_number: 123412341234 Deploy - Time In Cache Friday, May 10, 13
- 45. WHAT HAPPENS ? name: 'roger' age: 23 card_type: 'visa' card_number: 123412341234 Deploy name: 'roger' age: 24 card_type: 'visa' card_number: 123412341234 - Time In Cache Update Friday, May 10, 13
- 46. WHAT HAPPENS ? name: 'roger' age: 23 card_type: 'visa' card_number: 123412341234 Deploy name: 'roger' age: 24 card_type: 'visa' card_number: 123412341234 Save - Time In Cache Update Friday, May 10, 13
- 47. WHAT HAPPENS ? name: 'roger' age: 23 card_type: 'visa' card_number: 123412341234 Deploy name: 'roger' age: 24 card_type: 'visa' card_number: 123412341234 Save Database Exception unknown columns card_type, card_number - Time In Cache Update Friday, May 10, 13
- 48. WHAT HAPPENS ? name: 'roger' age: 23 card_type: 'visa' card_number: 123412341234 Deploy name: 'roger' age: 24 card_type: 'visa' card_number: 123412341234 Save Database Exception unknown columns card_type, card_number - Time In Cache Update Friday, May 10, 13
- 49. IGNORE COLUMNS - class User def columns self.class.columns.reject do |c| (self.class.deprecated_attributes || []).include? c.name.to_s end end end Friday, May 10, 13