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+##
+# This module is for replacing `dependent: :destroy` and `before_destroy` hooks.
+#
+# In general, `destroy_all` is inefficient because it calls each callback with `DELETE` queries i.e. O(n), whereas,
+# `delete_all` is efficient as it deletes all rows with a single `DELETE` query.
+#
+# It's better to use `delete_all` as our best practice, however,
+# if external data (e.g. ObjectStorage, FileStorage or Redis) are assosiated with database records,
+# it is difficult to accomplish it.
+#
+# This module defines a format to use `delete_all` and delete associated external data.
+# Here is an exmaple
+#
+# Situation
+# - `Project` has many `Ci::BuildTraceChunk` through `Ci::Build`
+# - `Ci::BuildTraceChunk` stores associated data in Redis, so it relies on `dependent: :destroy` and `before_destroy` for the deletion
+#
+# How to use
+# - Define `use_fast_destroy :build_trace_chunks` in `Project` model.
+# - Define `begin_fast_destroy` and `finalize_fast_destroy(params)` in `Ci::BuildTraceChunk` model.
+# - Use `fast_destroy_all` instead of `destroy` and `destroy_all`
+# - Remove `dependent: :destroy` and `before_destroy` as it's no longer need
+#
+# Expectation
+# - When a project is `destroy`ed, the associated trace_chunks will be deleted by `delete_all`,
+# and the associated data will be removed, too.
+# - When `fast_destroy_all` is called, it also performns as same.
+module FastDestroyAll
+ extend ActiveSupport::Concern
+
+ ForbiddenActionError = Class.new(StandardError)
+
+ included do
+ before_destroy do
+ raise ForbiddenActionError, '`destroy` and `destroy_all` are forbbiden. Please use `fast_destroy_all`'
+ end
+ end
+
+ class_methods do
+ ##
+ # This method delete rows and associated external data efficiently
+ #
+ # This method can replace `destroy` and `destroy_all` without having `after_destroy` hook
+ def fast_destroy_all
+ params = begin_fast_destroy
+
+ delete_all
+
+ finalize_fast_destroy(params)
+ end
+
+ ##
+ # This method returns identifiers to delete associated external data (e.g. file paths, redis keys)
+ #
+ # This method must be defined in fast destroyable model
+ def begin_fast_destroy
+ raise NotImplementedError
+ end
+
+ ##
+ # This method deletes associated external data with the identifiers returned by `begin_fast_destroy`
+ #
+ # This method must be defined in fast destroyable model
+ def finalize_fast_destroy(params)
+ raise NotImplementedError
+ end
+ end
+
+ module Helpers
+ extend ActiveSupport::Concern
+
+ class_methods do
+ ##
+ # This method is to be defined on models which have fast destroyable models as children,
+ # and let us avoid to use `dependent: :destroy` hook
+ def use_fast_destroy(relation)
+ before_destroy(prepend: true) do
+ perform_fast_destroy(public_send(relation)) # rubocop:disable GitlabSecurity/PublicSend
+ end
+ end
+ end
+
+ def perform_fast_destroy(subject)
+ params = subject.begin_fast_destroy
+
+ run_after_commit do
+ subject.finalize_fast_destroy(params)
+ end
+ end
+ end
+end