Module: Annotations::Util

Defined in:
lib/annotations/util.rb

Class Method Summary collapse

Class Method Details

.migrate_annotations_to_v3 ⇒ Object

Migrate existing annotations to the v3 db schema.

Currently it just copies all values over to TextValue entries and assigns ‘value’ of the annotation accordingly and fixes up all the versions of that annotation in a naive way.

NOTE (1): If you need tdifferent migration behaviour, redefine this method in your app (in the same namespace).

NOTE (2): if individual annotations fail to migrate, their IDs and error info will be outputted to the console so you can inspect the issue.

NOTE (3): this won’t migrate any AnnotationValueSeed entries. You will need to write another migration script/method for these.

NOTE (4): this makes some big assumptions about your current set of annotations. Please look through to make sure the logic applies.



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# File 'lib/annotations/util.rb', line 22

def self.migrate_annotations_to_v3
  Annotation.record_timestamps = false
  
  Annotation.all.each do |ann|
    begin
      ann.transaction do
        val = TextValue.new
        
        # Handle versions
        #
        # NOTE: This will take a naive approach of assuming that
        # only the 'old_value' field has been changed over time,
        # nothing else!
        
        # Build up the TextValue from the versions
        ann.versions.each do |version|
          val.text = version.old_value
          val.created_at = version.created_at unless val.created_at
          val.updated_at = version.updated_at
          val.save!
          
          val_version = val.versions(true).last
          val_version.created_at = version.created_at
          val_version.updated_at = version.updated_at
          val_version.save!
        end
        
        # Assign new TextValue to Annotation
        ann.value = val
        ann.save!
        
        # Only keep second to last version,
        # deleting others, and resetting version
        # numbers.
        ann.versions(true).each do |version|
          if version == ann.versions[-2]
            # The one we want to keep
            version.version = 1
            version.value = val
            version.save!
          else
            # Delete!
            version.destroy
          end
        end
        ann.version = 1
        ann.save!    # This shouldn't result in a new version
      end
    rescue Exception => ex
      puts "FAILED to migrate annotation with ID #{ann.id}. Error message: #{ex.message}"
    end
  end
  
  # TODO: similar kind of migration for annotation value seeds
  
  Annotation.record_timestamps = true    
end