Use a cache

Gemfile

@@ -18,6 +18,7 @@ gem 'aws-sdk-sesv2'
 gem 'anycable-rails', '~> 1.2.0'
 gem 'grpc', '>= 1.53.0'
 gem 'crawler_detect'
+gem 'xxhash'
 
 # Serving requests
 gem 'puma', '~> 4.3'

Gemfile.lock

@@ -550,6 +550,7 @@ GEM
     websocket-extensions (0.1.5)
     xpath (3.2.0)
       nokogiri (~> 1.8)
+    xxhash (0.6.0)
     yard (0.9.36)
     zeitwerk (2.6.8)
 
@@ -631,6 +632,7 @@ DEPENDENCIES
   tzinfo-data
   web-console (>= 3.3.0)
   webmock
+  xxhash
 
 RUBY VERSION
    ruby 3.3.0p0

app/assemblers/assemble_code_tag_samples.rb

@@ -21,7 +21,7 @@ def samples
     )
   end
 
-  def track = params[:track_slug].present? && Track.find(params[:track_slug])
+  def track = params[:track_slug].present? && Track.cached.find_by!(slug: params[:track_slug])
   def status = params.fetch(:status, :needs_tagging).to_sym
   def page = [params[:page].to_i, 1].max
 end

app/assemblers/assemble_community_videos.rb

@@ -24,6 +24,6 @@ def videos
 
   memoize
   def track
-    Track.find(params[:video_track_slug]) if params[:video_track_slug].present?
+    Track.cached.find_by!(slug: params[:video_track_slug]) if params[:video_track_slug].present?
   end
 end

app/assemblers/assemble_contributors.rb

@@ -21,7 +21,7 @@ def starting_rank
 
   memoize
   def track_id
-    Track.find(params[:track_slug]).id if params[:track_slug].present?
+    Track.cached.find_by!(slug: params[:track_slug]).id if params[:track_slug].present?
   end
 
   memoize

app/assemblers/assemble_exercise_representations_admin.rb

@@ -31,6 +31,6 @@ def representations
     )
   end
 
-  def track = Track.find_by(slug: params[:track_slug])
+  def track = Track.cached.find_by(slug: params[:track_slug])
   def representer_version = track.representations.maximum(:representer_version) || 1
 end

app/assemblers/assemble_journey_overview.rb

@@ -28,7 +28,7 @@ def call
 
   private
   def learning_tracks_data
-    user.user_tracks.includes(:track).map do |user_track|
+    user.user_tracks.map do |user_track|
       track = user_track.track
 
       first_completion = user_track.exercise_completion_dates.min

app/assemblers/assemble_tasks.rb

@@ -30,6 +30,6 @@ def tasks
 
   memoize
   def track_id
-    Track.find(params[:track_slug]).id if params[:track_slug].present?
+    Track.cached.find_by!(slug: params[:track_slug]).id if params[:track_slug].present?
   end
 end

app/commands/mentor/request/retrieve_exercises.rb

@@ -23,7 +23,7 @@ def call
 
   memoize
   def track
-    Track.find(track_slug)
+    Track.cached.find_by!(slug: track_slug)
   end
 
   memoize

app/commands/user/challenges/featured_exercises_progress_48_in_24.rb

@@ -93,7 +93,7 @@ def completions
 
   memoize
   def csharp_exercises
-    Track.find('csharp').practice_exercises.index_by(&:slug)
+    Track.cached.find_by!(slug: 'csharp').practice_exercises.index_by(&:slug)
   rescue ActiveRecord::RecordNotFound
     {}
   end

app/commands/user/insiders_status/update.rb

@@ -78,7 +78,7 @@ def update_to_eligible
 
   def update_to_ineligible
     user.update!(insiders_status: :ineligible)
-    user.preferences.update(theme: DEFAULT_THEME) if uses_insiders_only_theme?
+    user.preferences.update!(theme: DEFAULT_THEME) if uses_insiders_only_theme?
   end
 
   def uses_insiders_only_theme? = INSIDERS_ONLY_THEMES.include?(user.preferences.theme)

app/commands/user/update_flair.rb

@@ -5,7 +5,9 @@ class User::UpdateFlair
 
   initialize_with :user
 
-  def call = user.update!(flair:)
+  def call
+    user.update!(flair:)
+  end
 
   private
   memoize

app/controllers/api/community_solution_comments_controller.rb

@@ -60,7 +60,7 @@ def disable
 
   private
   def use_solution
-    @track = Track.find(params[:track_slug])
+    @track = Track.cached.find_by!(slug: params[:track_slug])
     @exercise = @track.exercises.find(params[:exercise_slug])
     user = User.find_by!(handle: params[:community_solution_handle])
     @solution = @exercise.solutions.find_by!(user_id: user.id)

app/controllers/api/community_solution_stars_controller.rb

@@ -25,7 +25,7 @@ def destroy
 
   private
   def use_solution
-    @track = Track.find(params[:track_slug])
+    @track = Track.cached.find_by!(slug: params[:track_slug])
     @exercise = @track.exercises.find(params[:exercise_slug])
     user = User.find_by!(handle: params[:community_solution_handle])
     @solution = @exercise.solutions.published.find_by!(user_id: user.id)

app/controllers/api/community_solutions_controller.rb

@@ -9,7 +9,7 @@ def index
 
   private
   def use_exercise
-    @track = Track.find(params[:track_slug])
+    @track = Track.cached.find_by!(slug: params[:track_slug])
     @exercise = @track.exercises.find(params[:exercise_slug])
   end
 

app/controllers/api/community_videos_controller.rb

@@ -17,7 +17,7 @@ def lookup
   def create
     if params[:track_slug].present?
       begin
-        track = Track.find(params[:track_slug])
+        track = Track.cached.find_by!(slug: params[:track_slug])
       rescue ActiveRecord::RecordNotFound
         return render_track_not_found
       end

app/controllers/api/concepts/makers_controller.rb

@@ -28,7 +28,7 @@ def index
 
   private
   def use_concept
-    @track = Track.find(params[:track_slug])
+    @track = Track.cached.find_by!(slug: params[:track_slug])
     @concept = @track.concepts.find(params[:concept_slug])
   end
 end

app/controllers/api/exercises/makers_controller.rb

@@ -28,7 +28,7 @@ def index
 
   private
   def use_exercise
-    @track = Track.find(params[:track_slug])
+    @track = Track.cached.find_by!(slug: params[:track_slug])
     @exercise = @track.exercises.find(params[:exercise_slug])
   end
 end

app/controllers/api/exercises_controller.rb

@@ -20,7 +20,7 @@ def start
 
   private
   def use_track
-    @track = Track.find(params[:track_slug])
+    @track = Track.cached.find_by!(slug: params[:track_slug])
   end
 
   def use_exercise

app/controllers/api/export_solutions_controller.rb

@@ -10,7 +10,7 @@ def index
 
   private
   def use_track
-    @track = Track.find(params[:track_slug])
+    @track = Track.cached.find_by!(slug: params[:track_slug])
   rescue ActiveRecord::RecordNotFound
     render_track_not_found
   end

app/controllers/api/hiring_controller.rb

@@ -4,7 +4,7 @@ class API::HiringController < API::BaseController
   def testimonials
     user = User.find_by(handle: 'bobahop')
     testimonials = user.mentor_testimonials.published.joins(solution: { exercise: :track })
-    testimonials = testimonials.where('exercises.track_id': Track.find(params[:track]).id) if params[:track]
+    testimonials = testimonials.where('exercises.track_id': Track.cached.find_by!(slug: params[:track]).id) if params[:track]
     testimonials = testimonials.where('exercises.title LIKE ?', "%#{params[:exercise]}%") if params[:exercise]
     testimonials = testimonials.order(id: params[:order] == "newest_first" ? :desc : :asc)
     testimonials = testimonials.page(params[:page]).per(20)

app/controllers/api/mentoring/requests_controller.rb

@@ -2,7 +2,7 @@ class API::Mentoring::RequestsController < API::BaseController
   def index
     begin
       if params[:track_slug].present?
-        track_id = Track.find(params[:track_slug]).id
+        track_id = Track.cached.find_by!(slug: params[:track_slug]).id
         current_user.track_mentorships.update_all("last_viewed = (track_id = #{track_id})")
       end
     rescue StandardError

app/controllers/api/tracks/solutions_for_mentoring_controller.rb

@@ -1,6 +1,6 @@
 class API::Tracks::SolutionsForMentoringController < API::BaseController
   def index
-    track = Track.find(params[:track_slug])
+    track = Track.cached.find_by!(slug: params[:track_slug])
     solutions = Track::SearchSolutionsForMentoring.(current_user, track, page: params[:page])
 
     render json: SerializePaginatedCollection.(

app/controllers/api/tracks/tags_controller.rb

@@ -25,7 +25,7 @@ def not_enabled
 
   private
   def use_track
-    @track = Track.find(params[:track_slug])
+    @track = Track.cached.find_by!(slug: params[:track_slug])
   rescue StandardError
     render_404(:track_not_found)
   end

app/controllers/api/tracks/trophies_controller.rb

@@ -1,13 +1,13 @@
 class API::Tracks::TrophiesController < API::BaseController
   def index
-    track = Track.find(params[:track_slug])
+    track = Track.cached.find_by!(slug: params[:track_slug])
 
     render json: { trophies: SerializeTrackTrophies.(track, current_user) }
   end
 
   def reveal
     begin
-      track = Track.find(params[:track_slug])
+      track = Track.cached.find_by!(slug: params[:track_slug])
     rescue StandardError
       return render_404(:track_not_found, fallback_url: tracks_url)
     end

app/controllers/api/user_tracks_controller.rb

@@ -39,7 +39,7 @@ def leave
 
   private
   def use_track
-    @track = Track.find(params[:slug])
+    @track = Track.cached.find_by!(slug: params[:slug])
     # TODO: Rescue and handle
     @user_track = UserTrack.for!(current_user, @track)
   end

app/controllers/concerns/use_track_exercise_solution_concern.rb

@@ -12,7 +12,7 @@ module UseTrackExerciseSolutionConcern
   extend Mandate::Memoize
 
   def use_track!
-    @track = Track.find(params[:track_id])
+    @track = Track.cached.find_by!(slug: params[:track_id])
     @user_track = UserTrack.for(current_user, @track)
 
     render_404 unless @track.accessible_by?(current_user)

app/controllers/docs_controller.rb

@@ -33,7 +33,7 @@ def use_section
   end
 
   def use_track
-    @track = Track.find(params[:track_slug])
+    @track = Track.cached.find_by!(slug: params[:track_slug])
     @nav_docs = Document.where(track_id: @track.id)
 
     render_404 unless @track.accessible_by?(current_user)

app/controllers/impact_controller.rb

@@ -2,7 +2,7 @@ class ImpactController < ApplicationController
   skip_before_action :authenticate_user!
 
   def index
-    @track = Track.find(params[:track_slug]) if params[:track_slug].present?
+    @track = Track.cached.find_by!(slug: params[:track_slug]) if params[:track_slug].present?
     @last_24_hours = last_24_hours
     @last_month = last_month
   end

app/controllers/maintaining/site_updates_controller.rb

@@ -1,7 +1,7 @@
 class Maintaining::SiteUpdatesController < Maintaining::BaseController
   def index
     @updates = SiteUpdate.sorted
-    @updates = @updates.for_track(Track.find(params[:track_slug])) if params[:track_slug].present?
+    @updates = @updates.for_track(Track.cached.find_by!(slug: params[:track_slug])) if params[:track_slug].present?
     @updates = @updates.page(params[:page]).per(30)
   end
 

app/controllers/pages_controller.rb

@@ -5,7 +5,7 @@ def index
     return redirect_to dashboard_path if user_signed_in?
 
     @tracks = Track.active.order(num_students: :desc).limit(12).to_a
-    @num_tracks = Track.active.count
+    @num_tracks = Track.num_active
 
     @showcase_exercises = [
       {

app/controllers/partners_controller.rb

@@ -7,7 +7,7 @@ def show
   end
 
   def gobridge
-    @track = Track.find('go')
+    @track = Track.cached.find_by!(slug: 'go')
     @num_concepts = @track.concepts.count
     @num_exercises = @track.exercises.count
     @num_tasks = @track.tasks.count

app/controllers/sitemaps_controller.rb

@@ -74,7 +74,7 @@ def profiles
   end
 
   def track
-    track = Track.find(params[:track_id])
+    track = Track.cached.find_by!(slug: params[:track_id])
     pages = []
     pages << [track_url(track), track.updated_at, :monthly, 0.9]
     pages << [track_concepts_url(track), track.updated_at, :monthly, 0.85] if track.course?

app/controllers/temp/tracks/exercises_controller.rb

@@ -7,7 +7,7 @@ class Tracks::ExercisesController < ApplicationController
 
     private
     def use_track
-      @track = Track.find(params[:track_id])
+      @track = Track.cached.find_by!(slug: params[:track_id])
       @user_track = UserTrack.for(current_user, @track)
 
       render_404 unless @track.accessible_by?(current_user)

app/controllers/tracks/approaches_controller.rb

@@ -23,7 +23,7 @@ def show
 
   private
   def use_solution
-    @track = Track.find(params[:track_id])
+    @track = Track.cached.find_by!(slug: params[:track_id])
     @user_track = UserTrack.for(current_user, @track)
     @exercise = @track.exercises.find(params[:exercise_id])
     @solution = Solution.for(current_user, @exercise)

app/controllers/tracks/articles_controller.rb

@@ -21,7 +21,7 @@ def show
 
   private
   def use_solution
-    @track = Track.find(params[:track_id])
+    @track = Track.cached.find_by!(slug: params[:track_id])
     @user_track = UserTrack.for(current_user, @track)
     @exercise = @track.exercises.find(params[:exercise_id])
     @solution = Solution.for(current_user, @exercise)

app/controllers/tracks/concepts_controller.rb

@@ -50,7 +50,7 @@ def tooltip
 
   private
   def use_track
-    @track = Track.find(params[:track_id])
+    @track = Track.cached.find_by!(slug: params[:track_id])
     @user_track = UserTrack.for(current_user, @track)
 
     render_404 unless @track.accessible_by?(current_user)

app/controllers/tracks/dig_deeper_controller.rb

@@ -17,7 +17,7 @@ def tooltip_locked = render_template_as_json
 
   private
   def use_solution
-    @track = Track.find(params[:track_id])
+    @track = Track.cached.find_by!(slug: params[:track_id])
     @user_track = UserTrack.for(current_user, @track)
     @exercise = @track.exercises.find(params[:exercise_id])
     @solution = Solution.for(current_user, @exercise)

app/controllers/tracks/mentor_requests_controller.rb

@@ -37,7 +37,7 @@ def show
 
   private
   def use_solution
-    @track = Track.find(params[:track_id])
+    @track = Track.cached.find_by!(slug: params[:track_id])
     @user_track = UserTrack.for(current_user, @track)
     @exercise = @track.exercises.find(params[:exercise_id])
     @solution = Solution.for(current_user, @exercise)

app/controllers/tracks_controller.rb

@@ -10,7 +10,7 @@ def index
       user: current_user
     )
 
-    @num_tracks = Track.active.count
+    @num_tracks = Track.num_active
 
     # TODO: (Optional) Change this to only select the fields needed for an icon
     @track_icon_urls = Track.active.order('rand()').limit(8).map(&:icon_url)
@@ -49,7 +49,7 @@ def join
 
   private
   def use_track
-    @track = Track.find(params[:id])
+    @track = Track.cached.find_by!(slug: params[:id])
     @user_track = UserTrack.for(current_user, @track)
 
     render_404 unless @track.accessible_by?(current_user)

app/helpers/react_components/modals/welcome_modal.rb

@@ -15,7 +15,7 @@ def to_s
         super(
           "modals-welcome-modal",
           {
-            num_tracks: ::Track.active.count,
+            num_tracks: ::Track.num_active,
             links: {
               hide_modal_endpoint: Exercism::Routes.hide_api_settings_introducer_path(slug),
               api_user_endpoint: Exercism::Routes.api_user_url,

app/helpers/view_components/site_footer.rb

@@ -17,7 +17,7 @@ def to_s
     def cache_key
       parts = digests
       parts << Date.current.year
-      parts << ::Track.active.count
+      parts << ::Track.num_active
       parts << user_part
       parts << stripe_version
       parts << "v3"