Memorize config options instead of reading them from file over and over again

app/controllers/application_controller.rb

@@ -5,6 +5,7 @@ class ApplicationController < ActionController::Base
   include Pundit::Authorization
 
   MEMBER_ACTIONS = %i[destroy edit show update].freeze
+  RENDER_HOST = CodeOcean::Config.new(:code_ocean).read[:render_host]
 
   after_action :verify_authorized, except: %i[welcome]
   around_action :mnemosyne_trace

app/helpers/exercise_helper.rb

@@ -3,6 +3,8 @@
 module ExerciseHelper
   include LtiHelper
 
+  CODEPILOT_CONFIG = CodeOcean::Config.new(:code_ocean).read[:code_pilot]
+
   def embedding_parameters(exercise)
     "locale=#{I18n.locale}&token=#{exercise.token}"
   end
@@ -12,11 +14,6 @@ module ExerciseHelper
   end
 
   def qa_url
-    config = CodeOcean::Config.new(:code_ocean)
-    enabled = config.read[:code_pilot][:enabled]
-
-    if enabled
-      config.read[:code_pilot][:url]
-    end
+    CODEPILOT_CONFIG[:url] if CODEPILOT_CONFIG[:enabled]
   end
 end

app/policies/codeharbor_link_policy.rb

@@ -1,6 +1,8 @@
 # frozen_string_literal: true
 
 class CodeharborLinkPolicy < ApplicationPolicy
+  CODEHARBOR_CONFIG = CodeOcean::Config.new(:code_ocean).read[:codeharbor]
+
   def index?
     false
   end
@@ -30,7 +32,7 @@ class CodeharborLinkPolicy < ApplicationPolicy
   end
 
   def enabled?
-    CodeOcean::Config.new(:code_ocean).read[:codeharbor][:enabled]
+    CODEHARBOR_CONFIG[:enabled]
   end
 
   private

spec/controllers/codeharbor_links_controller_spec.rb

@@ -5,12 +5,9 @@ require 'rails_helper'
 describe CodeharborLinksController do
   let(:user) { create(:teacher) }
 
-  let(:codeocean_config) { instance_double(CodeOcean::Config) }
-  let(:codeharbor_config) { {codeharbor: {enabled: true, url: 'https://test.url'}} }
-
   before do
-    allow(CodeOcean::Config).to receive(:new).with(:code_ocean).and_return(codeocean_config)
-    allow(codeocean_config).to receive(:read).and_return(codeharbor_config)
+    allow(CodeharborLinkPolicy::CODEHARBOR_CONFIG).to receive(:[]).with(:enabled).and_return(true)
+    allow(CodeharborLinkPolicy::CODEHARBOR_CONFIG).to receive(:[]).with(:url).and_return('https://test.url')
     allow(controller).to receive(:current_user).and_return(user)
   end
 

spec/policies/codeharbor_link_policy_spec.rb

@@ -8,12 +8,8 @@ describe CodeharborLinkPolicy do
   let(:codeharbor_link) { create(:codeharbor_link) }
 
   context 'when CodeHarbor link is enabled' do
-    let(:codeocean_config) { instance_double(CodeOcean::Config) }
-    let(:codeharbor_config) { {codeharbor: {enabled: true}} }
-
     before do
-      allow(CodeOcean::Config).to receive(:new).with(:code_ocean).and_return(codeocean_config)
-      allow(codeocean_config).to receive(:read).and_return(codeharbor_config)
+      allow(CodeharborLinkPolicy::CODEHARBOR_CONFIG).to receive(:[]).with(:enabled).and_return(true)
     end
 
     %i[index? show?].each do |action|
@@ -64,12 +60,8 @@ describe CodeharborLinkPolicy do
   end
 
   context 'when CodeHabor link is disabled' do
-    let(:codeocean_config) { instance_double(CodeOcean::Config) }
-    let(:codeharbor_config) { {codeharbor: {enabled: false}} }
-
     before do
-      allow(CodeOcean::Config).to receive(:new).with(:code_ocean).and_return(codeocean_config)
-      allow(codeocean_config).to receive(:read).and_return(codeharbor_config)
+      allow(CodeharborLinkPolicy::CODEHARBOR_CONFIG).to receive(:[]).with(:enabled).and_return(false)
     end
 
     permissions :enabled? do