Merge branch '18337-cache-html-in-database' into 'master'

Cache rendered Markdown fields in the database

## What does this MR do?

Introduces cache fields for Markdown-containing fields in the database, and populates them.

## Why was this MR needed?

Rendering Markdown into HTML is performance-intensive. A Redis cache already exists, but this approach is expected to be more performant and reduce unnecessary cache invalidations.

## What are the relevant issue numbers?

Closes #18337

See merge request !6095

1 files changed, 10 insertions, 0 deletions

diff --git a/app/models/snippet.rb b/app/models/snippet.rb
index 8a1730f3f36..2373b445009 100644
--- a/app/models/snippet.rb
+++ b/app/models/snippet.rb
@@ -1,11 +1,21 @@
 class Snippet < ActiveRecord::Base
   include Gitlab::VisibilityLevel
   include Linguist::BlobHelper
+  include CacheMarkdownField
   include Participable
   include Referable
   include Sortable
   include Awardable
 
+  cache_markdown_field :title, pipeline: :single_line
+  cache_markdown_field :content
+
+  # If file_name changes, it invalidates content
+  alias_method :default_content_html_invalidator, :content_html_invalidated?
+  def content_html_invalidated?
+    default_content_html_invalidator || file_name_changed?
+  end
+
   default_value_for :visibility_level, Snippet::PRIVATE
 
   belongs_to :author, class_name: 'User'