easy-going-rails/config/initializers/instrumentalizing.rb

return unless Rails.application.server?

Rails.application.config.x.action_controller.main_session_tag = 'toto1'
Rails.application.config.x.action_controller.main_session_tag_fixed_length = 8

def build_instrumentation_config
  {
    action_controller: true,
    action_view: Live::Constants::ACTION_VIEW,
    active_record: Live::Constants::ACTIVE_RECORD
  }.map do |key, value|
    key if value
  end.compact
end

Rails.configuration.after_initialize do
  RailsSemanticLogger::Rack::Logger.logger.level = :info # useful for remaining log like "[Rack::Log] Started..."
  Rails.logger.name = 'rails'

  if Rails.env.production?

    formatter = Rails.application.config.x.semantic.formatter.constantize.new
    SemanticLogger.add_appender(appender: :syslog, formatter:)
    Semantic::Instrumentalizer.activate(*build_instrumentation_config)

  else
    SemanticLogger.clear_appenders!
    SemanticLogger.add_appender(
      io: $stdout,
      formatter: Rails.application.config.x.semantic.formatter.constantize.new
    )

    Rails.autoloaders.main.on_load('ApplicationController') do
      SemanticLogger.clear_appenders!
      SemanticLogger.add_appender(
        io: $stdout,
        formatter: Rails.application.config.x.semantic.formatter.constantize.new
      )

      Rails.logger.info ' ', dimensions: Semantic::FancyDimensions.new(rails: '╔═╗', before: 1)
      Rails.logger.fatal 'Zeitwerk RELOAD!', dimensions: Semantic::FancyDimensions.new(rails: '╠█╣')
      Rails.logger.info ' ', dimensions: Semantic::FancyDimensions.new(rails: '╚═╝')

      Semantic::Instrumentalizer.activate(*build_instrumentation_config)
    end
    ActiveSupport::Notifications.subscribe('rolling.live_constant') do |event|
      constants = event.payload[:changes].map { |change| change[:constant] }
      if constants.intersection(%w[ACTIVE_RECORD ACTION_VIEW]).any?
        Semantic::Instrumentalizer.activate(*build_instrumentation_config)
      end
    end
  end
end