Warn if there are configuration keys in the configuration file that are not loaded by the configuration store

.gitlab-ci.yml

@@ -209,7 +209,7 @@ specs:
     - cp -a keys.example keys
     - cp -a certs.example certs
     - cp pwned_passwords/pwned_passwords.txt.sample pwned_passwords/pwned_passwords.txt
-    - "echo -e \"test:\n  redis_url: 'redis://redis:6379/0'\n  redis_throttle_url: 'redis://redis:6379/1'\n  redis_irs_attempt_api_url: 'redis://redis:6379/2'\" > config/application.yml"
+    - "echo -e \"test:\n  redis_url: 'redis://redis:6379/0'\n  redis_throttle_url: 'redis://redis:6379/1'\" > config/application.yml"
     - bundle exec rake db:create db:migrate --trace
     - bundle exec rake db:seed
     - bundle exec rake knapsack:rspec["--format documentation --format RspecJunitFormatter --out rspec.xml --format json --out rspec_json/${CI_NODE_INDEX}.json"]

config/initializers/unused_identity_config_keys.rb

@@ -0,0 +1,3 @@
+if IdentityConfig.unused_keys.present?
+  Rails.logger.warn({ name: 'unused_identity_config_keys', keys: IdentityConfig.unused_keys })
+end

lib/identity_config.rb

@@ -6,7 +6,7 @@ class IdentityConfig
   VENDOR_STATUS_OPTIONS = %i[operational partial_outage full_outage]
 
   class << self
-    attr_reader :store, :key_types
+    attr_reader :store, :key_types, :unused_keys
   end
 
   CONVERTERS = {
@@ -492,6 +492,7 @@ def self.build_store(config_map)
     config.add(:weekly_auth_funnel_report_config, type: :json)
 
     @key_types = config.key_types
+    @unused_keys = config_map.keys - config.written_env.keys
     @store = RedactedStruct.new('IdentityConfig', *config.written_env.keys, keyword_init: true).
       new(**config.written_env)
   end

spec/lib/identity_config_spec.rb

@@ -65,4 +65,10 @@
       end
     end
   end
+
+  describe '.unused_keys' do
+    it 'does not have any unused keys' do
+      expect(IdentityConfig.unused_keys).to be_empty
+    end
+  end
 end