Refactor CodeOcean::Config class

The new architecture memorizes settings (which we mostly did after reading the config so far) and also exposes the resulting file path as well as further settings.

This change is a prerequisite to define a dependency with Sprockets.

app/assets/javascripts/editor/editor.js.erb

@@ -27,7 +27,7 @@ var CodeOceanEditor = {
 
     lastCopyText: null,
 
-    <% @config ||= CodeOcean::Config.new(:code_ocean).read(erb: false) %>
+    <% @config ||= CodeOcean::Config.new(:code_ocean, erb: false).read %>
     // Important notice: Changing the config values requires any content-wise
     // modification for this file in the development environment. Lacking to do so
     // will result in the old, server-side cached serving of this file even across

lib/code_ocean/config.rb

@@ -2,12 +2,16 @@
 
 module CodeOcean
   class Config
-    def initialize(filename)
+    attr_reader :path, :read
-      @filename = filename
+
+    def initialize(filename, options = {})
+      @path = Rails.root.join('config', "#{filename}.yml#{options[:erb] ? '.erb' : ''}")
+      @read = parse(options)
     end
 
-    def read(options = {})
+    private
-      path = Rails.root.join('config', "#{@filename}.yml#{options[:erb] ? '.erb' : ''}")
+
+    def parse(options)
       if ::File.exist?(path)
         yaml_content = ::File.new(path, 'r').read || ''
         yaml_content = ERB.new(yaml_content).result if options[:erb]

lib/runner/strategy/docker_container_pool.rb

@@ -146,7 +146,7 @@ class Runner::Strategy::DockerContainerPool < Runner::Strategy
   def self.config
     @config ||= begin
       # Since the docker configuration file contains code that must be executed, we use ERB templating.
-      docker_config = CodeOcean::Config.new(:docker).read(erb: true)
+      docker_config = CodeOcean::Config.new(:docker, erb: true).read
       codeocean_config = CodeOcean::Config.new(:code_ocean).read[:runner_management] || {}
       # All keys in `docker_config` take precedence over those in `codeocean_config`
       docker_config.merge codeocean_config

spec/lib/code_ocean/config_spec.rb

@@ -30,7 +30,7 @@ RSpec.describe CodeOcean::Config do
 
     context 'with a .yml.erb file' do
       let(:path) { Rails.root.join('config', "#{filename}.yml.erb") }
-      let(:read) { described_class.new(filename).read(erb: true) }
+      let(:read) { described_class.new(filename, erb: true).read }
 
       context 'when the file is present' do
         before { File.write(path, {Rails.env.to_s => content}.to_yaml) }