Adds an environment variable to disable unstructured logging

changelogs/unreleased/jarv-env-for-disabling-unstructured-log.yml

+---
+title: Adds an environment variable override to disable unstructured logs
+merge_request: 39109
+author:
+type: other

config/initializers/lograge.rb

@@ -5,7 +5,7 @@ unless Gitlab::Runtime.sidekiq?
   Rails.application.configure do
     config.lograge.enabled = true
     # Store the lograge JSON files in a separate file
-    config.lograge.keep_original_rails_log = true
+    config.lograge.keep_original_rails_log = Gitlab::Utils.to_boolean(ENV.fetch('UNSTRUCTURED_RAILS_LOG', 'true'))
     # Don't use the Logstash formatter since this requires logstash-event, an
     # unmaintained gem that monkey patches `Time`
     config.lograge.formatter = Lograge::Formatters::Json.new

doc/administration/environment_variables.md

@@ -33,6 +33,7 @@ Variable | Type | Description
 `GITLAB_UNICORN_MEMORY_MIN`                | integer | The minimum memory threshold (in bytes) for the Unicorn worker killer
 `GITLAB_UNICORN_MEMORY_MAX`                | integer | The maximum memory threshold (in bytes) for the Unicorn worker killer
 `GITLAB_SHARED_RUNNERS_REGISTRATION_TOKEN` | string  | Sets the initial registration token used for GitLab Runners
+`UNSTRUCTURED_RAILS_LOG`                   | string  | Enables the unstructured log in addition to JSON logs (defaults to `true`)
 
 ## Complete database variables
 

lib/gitlab/app_logger.rb

@@ -5,7 +5,11 @@ module Gitlab
     LOGGERS = [Gitlab::AppTextLogger, Gitlab::AppJsonLogger].freeze
 
     def self.loggers
-      LOGGERS
+      if Gitlab::Utils.to_boolean(ENV.fetch('UNSTRUCTURED_RAILS_LOG', 'true'))
+        LOGGERS
+      else
+        [Gitlab::AppJsonLogger]
+      end
     end
 
     def self.primary_logger

spec/lib/gitlab/app_logger_spec.rb

@@ -19,4 +19,12 @@ RSpec.describe Gitlab::AppLogger do
 
     subject.info('Hello World!')
   end
+
+  it 'logs info to only the AppJsonLogger when unstructured logs are disabled' do
+    stub_env('UNSTRUCTURED_RAILS_LOG', 'false')
+    expect_any_instance_of(Gitlab::AppTextLogger).not_to receive(:info).and_call_original
+    expect_any_instance_of(Gitlab::AppJsonLogger).to receive(:info).and_call_original
+
+    subject.info('Hello World!')
+  end
 end