[1812] Stop okcomputer logging

Gemfile

@@ -94,3 +94,7 @@ group :test do
   gem "vcr", "~> 6.2"
   gem "webmock", "~> 3.18"
 end
+
+group :production do
+  gem "rails_semantic_logger"
+end

Gemfile.lock

@@ -349,6 +349,10 @@ GEM
     rails-html-sanitizer (1.6.0)
       loofah (~> 2.21)
       nokogiri (~> 1.14)
+    rails_semantic_logger (4.14.0)
+      rack
+      railties (>= 5.1)
+      semantic_logger (~> 4.13)
     railties (7.1.3.1)
       actionpack (= 7.1.3.1)
       activesupport (= 7.1.3.1)
@@ -435,6 +439,8 @@ GEM
       rexml
     ruby-progressbar (1.13.0)
     ruby2_keywords (0.0.5)
+    semantic_logger (4.15.0)
+      concurrent-ruby (~> 1.0)
     sentry-rails (5.10.0)
       railties (>= 5.0)
       sentry-ruby (~> 5.10.0)
@@ -580,6 +586,7 @@ DEPENDENCIES
   rack-attack
   rails (~> 7.1.3)
   rails-erd
+  rails_semantic_logger
   rladr (~> 1.2)
   rspec
   rspec-rails

config/environments/production.rb

@@ -96,4 +96,9 @@
   config.action_mailer.notify_settings = {
     api_key: ENV.fetch("GOVUK_NOTIFY_API_KEY"),
   }
+
+  config.log_level = :info                                # Or :warn, or :error
+  config.log_format = :json                               # For parsing in Logit
+  config.rails_semantic_logger.add_file_appender = false  # Don't log to file
+  config.active_record.logger = nil                       # Don't log SQL
 end

config/initializers/okcomputer.rb

@@ -1,7 +1,6 @@
 require_relative "../../lib/ok_computer_checks/zendesk_check"
 require_relative "../../lib/ok_computer_checks/notify_check"
 
-OkComputer.logger = Rails.logger
 OkComputer.mount_at = "health"
 
 OkComputer::Registry.register "postgresql", OkComputer::ActiveRecordCheck.new

config/initializers/semantic_logger.rb

@@ -0,0 +1,10 @@
+return unless defined?(SemanticLogger)
+
+Rails.application.configure do
+  config.semantic_logger.application = "" # This is added by logstash from its tags
+  config.log_tags = [:request_id]         # Prepend all log lines with the following tags
+end
+
+SemanticLogger.add_appender(io: $stdout, level: Rails.application.config.log_level, 
+formatter: Rails.application.config.log_format)
+Rails.application.config.logger.info('Application logging to STDOUT')