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Diffstat (limited to 'app/models/concerns/fast_destroy_all.rb')
-rw-r--r-- | app/models/concerns/fast_destroy_all.rb | 91 |
1 files changed, 91 insertions, 0 deletions
diff --git a/app/models/concerns/fast_destroy_all.rb b/app/models/concerns/fast_destroy_all.rb new file mode 100644 index 00000000000..7ea042c6742 --- /dev/null +++ b/app/models/concerns/fast_destroy_all.rb @@ -0,0 +1,91 @@ +## +# 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 |