Fixes #35420 - Drop boot_settings.rb for early settings

With Rails 7 require_relative no longer works in a Gemfile (maybe it's
Zeitwerk?). Currently we only support Rails 6.1 anyway and if we can't
use the mechanism for Rails 7 this mechanism should be removed.

An environment variable has been considered but in testing the
environment variable was not passed on and issues with the lockfile
showed up.

When we upgrade Rails to 7.0 a new mechnism needs to be found.

Gemfile

@@ -1,17 +1,9 @@
 # foreman plugins import this file therefore __FILE__ cannot be used
 FOREMAN_GEMFILE = __FILE__ unless defined? FOREMAN_GEMFILE
 
-require_relative 'config/boot_settings'
-
 source 'https://rubygems.org'
 
-gem 'rails', case SETTINGS[:rails]
-             when '6.1'
-               '~> 6.1.6.1'
-             else
-               raise "Unsupported Ruby on Rails version configured in settings.yaml: #{SETTINGS[:rails]}"
-             end
-
+gem 'rails', '~> 6.1.6.1'
 gem 'rest-client', '>= 2.0.0', '< 3', :require => 'rest_client'
 gem 'audited', '>= 4.9.0', '< 5'
 gem 'will_paginate', '~> 3.3'

app/services/foreman/env_settings_loader.rb

@@ -35,7 +35,6 @@ def settings_map
         'FOREMAN_WEBPACK_DEV_SERVER_HTTPS' => [:boolean, :webpack_dev_server_https],
         'FOREMAN_ASSETS_DEBUG' => [:boolean, :assets_debug],
         'FOREMAN_HSTS_ENABLED' => [:boolean, :hsts_enabled],
-        'FOREMAN_RAILS' => [:string, :rails],
         'FOREMAN_DOMAIN' => [:string, :domain],
         'FOREMAN_FQDN' => [:string, :fqdn],
         'FOREMAN_CORS_DOMAINS' => [:list, :cors_domains],

config/settings.rb

@@ -1,11 +1,10 @@
-require_relative 'boot_settings'
 require_relative '../app/services/foreman/version'
 require_relative '../app/services/foreman/env_settings_loader'
 
-root = File.expand_path(File.dirname(__FILE__) + "/..")
-settings_file = Rails.env.test? ? 'config/settings.yaml.test' : 'config/settings.yaml'
+settings_file = File.join(__dir__, Rails.env.test? ? 'settings.yaml.test' : 'settings.yaml')
 
-SETTINGS.merge! YAML.load(ERB.new(File.read("#{root}/#{settings_file}")).result) if File.exist?(settings_file)
+SETTINGS = {}
+SETTINGS.merge! YAML.load(ERB.new(File.read(settings_file)).result) if File.exist?(settings_file)
 SETTINGS[:version] = Foreman::Version.new
 
 # Load settings from env variables
@@ -21,15 +20,13 @@
   SETTINGS[setting] = SETTINGS.fetch(setting, true)
 end
 
-SETTINGS[:rails] = '%.1f' % SETTINGS[:rails] if SETTINGS[:rails].is_a?(Float) # unquoted YAML value
-
 unless SETTINGS[:domain] && SETTINGS[:fqdn]
   require 'facter'
   SETTINGS[:domain] ||= Facter.value(:domain) || Facter.value(:hostname)
   SETTINGS[:fqdn] ||= Facter.value(:fqdn)
 end
 
 # Load plugin config, if any
-Dir["#{root}/config/settings.plugins.d/*.yaml"].each do |f|
+Dir["#{__dir__}/settings.plugins.d/*.yaml"].each do |f|
   SETTINGS.merge! YAML.load(ERB.new(File.read(f)).result)
 end

config/settings.yaml.example

@@ -29,10 +29,6 @@
 # so only change this if you know what you're doing.
 :hsts_enabled: true
 
-# Ruby on Rails version (available: 6.1)
-# Defaults to 6.1
-#:rails: 6.1
-
 # Local administrative settings for application domain, fqdn, foreman URL,
 # administrator email address etc. If you don't have a Puppet provisioning
 # system you may want to change to setup your project on your local machine.

test/unit/foreman/env_settings_loader_test.rb

@@ -14,7 +14,6 @@ class EnvSettingsLoaderTest < ActiveSupport::TestCase
         'FOREMAN_WEBPACK_DEV_SERVER_HTTPS' => 'false',
         'FOREMAN_ASSETS_DEBUG' => 'false',
         'FOREMAN_HSTS_ENABLED' => 'false',
-        'FOREMAN_RAILS' => '5.2',
         'FOREMAN_DOMAIN' => 'example.com',
         'FOREMAN_FQDN' => 'foreman.example.com',
         'FOREMAN_CORS_DOMAINS' => 'https://foreman.example.com https://www.foreman.example.com',
@@ -48,7 +47,6 @@ class EnvSettingsLoaderTest < ActiveSupport::TestCase
         webpack_dev_server_https: false,
         assets_debug: false,
         hsts_enabled: false,
-        rails: '5.2',
         domain: 'example.com',
         fqdn: 'foreman.example.com',
         cors_domains: ['https://foreman.example.com', 'https://www.foreman.example.com'],