Rails + Fluentd

fluent-logger.yml

common: &common
  tag:           'my.mega.tag'
  fluent_host:   'my.mega.host'
  fluent_port:   24225
  severity_key:  'level'
  messages_type: 'string'

production:
  <<: *common

Gemfile

gem 'act-fluent-logger-rails'
gem 'lograge'

production.rb

config.logger = ActFluentLoggerRails::Logger.new
config.log_tags = [:request_id]
config.log_level = :info
config.lograge.enabled = true
config.lograge.formatter = Lograge::Formatters::Json.new

config.middleware.delete ActionDispatch::DebugExceptions

config.lograge.custom_options = lambda do |event|
  payload = { params: event.payload[:params].except('controller', 'action', 'format') }

  payload[:host] = Rails.application.secrets.hostname
  exception_object = event.payload[:exception_object]
  payload[:backtrace] = exception_object.backtrace.join("\n") unless exception_object.blank?

  payload
end