95 lines
3.3 KiB
Ruby
95 lines
3.3 KiB
Ruby
# frozen_string_literal: true
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module LooseForeignKey
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extend ActiveSupport::Concern
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# This concern adds loose foreign key support to ActiveRecord models.
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# Loose foreign keys allow delayed processing of associated database records
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# with similar guarantees than a database foreign key.
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#
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# TODO: finalize this later once the async job is in place
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#
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# Prerequisites:
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#
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# To start using the concern, you'll need to install a database trigger to the parent
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# table in a standard DB migration (not post-migration).
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#
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# > add_loose_foreign_key_support(:projects, :gitlab_main)
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#
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# Usage:
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#
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# > class Ci::Build < ApplicationRecord
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# >
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# > loose_foreign_key :security_scans, :build_id, on_delete: :async_delete, gitlab_schema: :gitlab_main
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# >
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# > # associations can be still defined, the dependent options is no longer necessary:
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# > has_many :security_scans, class_name: 'Security::Scan'
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# >
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# > end
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#
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# Options for on_delete:
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#
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# - :async_delete - deletes the children rows via an asynchronous process.
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# - :async_nullify - sets the foreign key column to null via an asynchronous process.
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#
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# Options for gitlab_schema:
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#
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# - :gitlab_ci
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# - :gitlab_main
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#
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# The value can be determined by calling `Model.gitlab_schema` where the Model represents
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# the model for the child table.
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#
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# How it works:
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#
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# When adding loose foreign key support to the table, a DELETE trigger is installed
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# which tracks the record deletions (stores primary key value of the deleted row) in
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# a database table.
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#
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# These deletion records are processed asynchronously and records are cleaned up
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# according to the loose foreign key definitions described in the model.
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#
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# The cleanup happens in batches, which reduces the likelyhood of statement timeouts.
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#
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# When all associations related to the deleted record are cleaned up, the record itself
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# is deleted.
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included do
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class_attribute :loose_foreign_key_definitions, default: []
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end
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class_methods do
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def loose_foreign_key(to_table, column, options)
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symbolized_options = options.symbolize_keys
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unless base_class?
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raise <<~MSG
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loose_foreign_key can be only used on base classes, inherited classes are not supported.
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Please define the loose_foreign_key on the #{base_class.name} class.
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MSG
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end
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on_delete_options = %i[async_delete async_nullify]
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gitlab_schema_options = [ApplicationRecord.gitlab_schema, Ci::ApplicationRecord.gitlab_schema]
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unless on_delete_options.include?(symbolized_options[:on_delete]&.to_sym)
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raise "Invalid on_delete option given: #{symbolized_options[:on_delete]}. Valid options: #{on_delete_options.join(', ')}"
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end
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unless gitlab_schema_options.include?(symbolized_options[:gitlab_schema]&.to_sym)
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raise "Invalid gitlab_schema option given: #{symbolized_options[:gitlab_schema]}. Valid options: #{gitlab_schema_options.join(', ')}"
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end
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definition = ActiveRecord::ConnectionAdapters::ForeignKeyDefinition.new(
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table_name.to_s,
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to_table.to_s,
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{
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column: column.to_s,
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on_delete: symbolized_options[:on_delete].to_sym,
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gitlab_schema: symbolized_options[:gitlab_schema].to_sym
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}
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)
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self.loose_foreign_key_definitions += [definition]
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end
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end
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end
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