From 8044440d7ad8c476d05e3e204ee26b9663738cea Mon Sep 17 00:00:00 2001 From: Stan Hu Date: Wed, 14 Aug 2019 21:50:52 -0700 Subject: Eliminate many Gitaly calls in discussions API Previously, the API to retrieve discussions from merge requests often generated hundreds of Gitaly calls to determine whether a system note should be shown to the user. It did this by: 1. Rendering the Markdown 2. Extracting cross-references from the Markdown 3. For cross-references that were commits, a Gitaly FindCommit RPC would be issued to validate that the commit exists. The last step is unnecessary because we don't need to display a commit if the user doesn't have access to the project in the first place. `RendersNotes#prepare_notes_for_rendering` is already used in `MergeRequestsController`, which is why we don't see N+1 Gitaly calls there. We use it here to optimize the note redaction process. Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/65957 --- lib/api/discussions.rb | 26 ++++++++++++++++---------- 1 file changed, 16 insertions(+), 10 deletions(-) (limited to 'lib/api/discussions.rb') diff --git a/lib/api/discussions.rb b/lib/api/discussions.rb index cc62ce22a1b..6c1acc3963f 100644 --- a/lib/api/discussions.rb +++ b/lib/api/discussions.rb @@ -4,6 +4,7 @@ module API class Discussions < Grape::API include PaginationParams helpers ::API::Helpers::NotesHelpers + helpers ::RendersNotes before { authenticate! } @@ -23,21 +24,15 @@ module API requires :noteable_id, types: [Integer, String], desc: 'The ID of the noteable' use :pagination end - # rubocop: disable CodeReuse/ActiveRecord + get ":id/#{noteables_path}/:noteable_id/discussions" do noteable = find_noteable(parent_type, params[:id], noteable_type, params[:noteable_id]) - notes = noteable.notes - .inc_relations_for_view - .includes(:noteable) - .fresh - - notes = notes.reject { |n| n.cross_reference_not_visible_for?(current_user) } + notes = readable_discussion_notes(noteable) discussions = Kaminari.paginate_array(Discussion.build_collection(notes, noteable)) present paginate(discussions), with: Entities::Discussion end - # rubocop: enable CodeReuse/ActiveRecord desc "Get a single #{noteable_type.to_s.downcase} discussion" do success Entities::Discussion @@ -226,13 +221,24 @@ module API helpers do # rubocop: disable CodeReuse/ActiveRecord - def readable_discussion_notes(noteable, discussion_id) + def readable_discussion_notes(noteable, discussion_id = nil) notes = noteable.notes - .where(discussion_id: discussion_id) + notes = notes.where(discussion_id: discussion_id) if discussion_id + notes = notes .inc_relations_for_view .includes(:noteable) .fresh + # Without RendersActions#prepare_notes_for_rendering, + # Note#cross_reference_not_visible_for? will attempt to render + # Markdown references mentioned in the note to see whether they + # should be redacted. For notes that reference a commit, this + # would also incur a Gitaly call to verify the commit exists. + # + # With prepare_notes_for_rendering, we can avoid Gitaly calls + # because notes are redacted if they point to projects that + # cannot be accessed by the user. + notes = prepare_notes_for_rendering(notes) notes.reject { |n| n.cross_reference_not_visible_for?(current_user) } end # rubocop: enable CodeReuse/ActiveRecord -- cgit v1.2.1