db_grep_associations.rake

https://gist.github.com/belt/c8f7b1c45834ce6fa485

desc 'Create a db/extracted_data.sql file for a given entity'
namespace :db do
  namespace :grep do
    task associations: :environment do
      obfuscate_sql if obfuscate
      Rails.application.eager_load!
      if dump_file_path.blank?
        puts grep_associations_to_sql
      else
        dump_to_sql_file
      end
    end

    def grep_associations_to_sql
      Polo.explore(klass, id, model_reflections[entity.classify])
    end

    def dump_to_sql_file
      puts "Writing #{dump_file_path.sub(Rails.root.to_s + '/', '')}"
      File.open dump_file_path, 'wb' do |file|
        file.write grep_associations_to_sql
      end
    end

    def model_reflections
      descendants = ActiveRecord::Base.descendants.map(&:to_s)
      @model_reflections ||= descendants.each_with_object({}) do |ar_class, result|
        reflections = ar_class.constantize.reflections.symbolize_keys.keys.sort
        reflections -= [:versions] unless capture_versions
        result[ar_class] = reflections
      end
    end

    # ------------------------------------------------------------------------
    # require parameters and validation there-of
    def fail_usage_message
      required = 'ENTITY=<table> ID=<integer>'
      optionals = '[FILE=[path]] [OBFUSCATE=<bool>] [VERSIONS=<bool>]'
      "try `rake #{ARGV[0]} #{required} #{optionals}`"
    end

    def invalid_class_message
      "#{entity} is not a descendant of ActiveRecord::Base"
    end

    def entity
      fail fail_usage_message unless env[:entity] || env[:ENTITY]
      (ENV['entity'] || ENV['ENTITY']).try(:classify)
    end

    def id
      fail fail_usage_message unless env[:id] || env[:ID]
      ENV['id'] || ENV['ID']
    end

    def klass
      fail fail_usage_msg unless entity
      @klass ||= entity.try(:constantize)
      fail invalid_class_message unless @klass && model_reflections.key?(entity)
      @klass
    end

    # ------------------------------------------------------------------------
    # optional parameters
    def dump_file_path
      @dump_file_path ||= ENV['file'] || ENV['FILE'] ||
                          Rails.root.join('db', 'extracted_data.sql')
    end

    def obfuscate
      @obfuscate = true
      obfuscate = ENV['obfuscate'] || ENV['OBFUSCATE']
      @obfuscate = false if %w(0 no false off).include? obfuscate.try :downcase
      @obfuscate
    end

    def capture_versions
      @capture_versions = true
      versions = ENV['versions'] || ENV['VERSIONS']
      @capture_versions = false if %w(0 no false off).include? versions.try :downcase
      @capture_versions
    end

    private

    def env
      @env ||= ENV.to_hash.symbolize_keys
    end

    def obfuscate_sql
      Polo.configure do
        obfuscate password_digest: ->(_) {'changeme'},
                  password_reset_digest: ->(_) {'changeme'},
                  reset_password_token: ->(_) {'changeme'}
      end
    end
  end
end

# The MIT License (MIT)
#
# Copyright (c) 2015 Paul Belt
# 
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
# 
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
# 
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
# SOFTWARE.