Extract Ruby on Rails enum values into a dictionary (represented by markdown tables).

extract_enum_mappings.md

README

Sometimes you have members from your data team who are looking at the database and have no idea what the enum integer values mean. This snippet of code helps to extract the readable names for those integers into markdown tables to help out your data team.

There are alternative approaches by using string enums via gems, or database enums, but this was made for an environment where those weren't an option (legacy enums, and no database enums available).

You could also put this into a Rake task and publish it into a wiki.

Usage

enum_mappings = extract_enum_mappings_from_all_models
markdown = enum_mappings_to_markdown(enum_mappings)

puts markdown

Check the sample below to see how the markdown looks like.

extract_enum_mappings.rb

def extract_enum_mappings(model_class)
  return nil unless model_class.table_exists?
  
  attribute_types = model_class.attribute_types
  enums = attribute_types.select{ |key, value| value.class == ActiveRecord::Enum::EnumType }
  
  return nil if enums.blank?
  
  enum_mappings = {}
  enum_values = enums.values
  
  enum_values.each do |enum_value|
    enum_mappings[enum_value.send(:name)] = enum_value.send(:mapping)
  end
  
  enum_mappings
end

# Returns a hash that looks like this:
# {
#    "User"=> {:values => {"type"=>{"customer"=>0, "developer"=>1} }, :table_name => "users"}, 
#    ...
# }
def extract_enum_mappings_from_all_models
  enum_mappings = {}
  
  ApplicationRecord.descendants.each do |model_class|
    enum_values = extract_enum_mappings(model_class)
    
    next if enum_values.blank?
    
    enum_mappings[model_class.name] = {
      values: extract_enum_mappings(model_class),
      table_name: model_class.table_name,
    }
  end
  
  enum_mappings.compact
end

def enum_mappings_to_markdown(enum_mappings)
  markdown = ""
  enum_mappings.each do |model_name, data|
    markdown += "# #{data[:table_name]}\n\n"
    
    data[:values].each do |attribute, values|
      markdown += "## #{attribute}\n\n"
      markdown += "| name | value |\n"
      markdown += "| ----------- | ----------- |\n"
      values.each do |value, id|
        markdown += "| #{value} | #{id} |\n"
      end
      
      markdown += "\n"
    end
  end

  markdown
end

sample_generated_markdown.md

users

status

name	value
unverified	0
verified	1
blocked	2

type

name	value
buyer	0
developer	1
merchant	2

orders

status

name	value
created	0
waiting_for_payment	1
payment_complete	2
shipped	3
delievered	4