I have a Rails application that has an action invoked frequently enough to be inconvenient when I am developing, as it results in a lot of extra log output I don't care about. How can I get rails not to log anything (controller, action, parameters, completion time, etc.) for just this one action? I'd like to conditionalize it on RAILS_ENV as well, so logs in production are complete.
Thanks!
You can silence the Rails logger object:
def action
Rails.logger.silence do
# Things within this block will not be logged...
end
end
The following works with at least Rails 3.1.0:
Make a custom logger that can be silenced:
# selective_logger.rb
class SelectiveLogger < Rails::Rack::Logger
def initialize app, opts = {}
@app = app
@opts = opts
@opts[:silenced] ||= []
end
def call env
if @opts[:silenced].include?(env['PATH_INFO']) || @opts[:silenced].any? {|silencer| silencer.is_a?( Regexp) && silencer.match( env['PATH_INFO']) }
Rails.logger.silence do
@app.call env
end
else
super env
end
end
end
Tell Rails to use it:
# application.rb
config.middleware.swap Rails::Rack::Logger, SelectiveLogger, :silenced => ["/remote/every_minute", %r"^/assets/"]
The example above shows silencing asset serving requests, which in the development environment means less ( and sometimes no) scrolling back is required to see the actual request.
The answer turns out to be a lot harder than I expected, since rails really does provide no hook to do this. Instead, you need to wrap some of the guts of ActionController::Base. In the common base class for my controllers, I do
def silent?(action)
false
end
# this knows more than I'd like about the internals of process, but
# the other options require knowing even more. It would have been
# nice to be able to use logger.silence, but there isn't a good
# method to hook that around, due to the way benchmarking logs.
def log_processing_with_silence_logs
if logger && silent?(action_name) then
@old_logger_level, logger.level = logger.level, Logger::ERROR
end
log_processing_without_silence_logs
end
def process_with_silence_logs(request, response, method = :perform_action, *arguments)
ret = process_without_silence_logs(request, response, method, *arguments)
if logger && silent?(action_name) then
logger.level = @old_logger_level
end
ret
end
alias_method_chain :log_processing, :silence_logs
alias_method_chain :process, :silence_logs
then, in the controller with the method I want to suppress logging on:
def silent?(action)
RAILS_ENV == "development" && ['my_noisy_action'].include?(action)
end
You can add the gem to the Gemfile silencer.
gem 'silencer', '>= 1.0.1'
And in your config/initializers/silencer.rb :
require 'silencer/logger'
Rails.application.configure do
config.middleware.swap Rails::Rack::Logger, Silencer::Logger, silence: ['/api/notifications']
end
With Rails 5 it gets more complicated request processing is logged in several classes. Firstly we need to override call_app in Logger class, let's call this file lib/logger.rb:
# original class:
# https://github.com/rails/rails/blob/master/railties/lib/rails/rack/logger.rb
require 'rails/rack/logger'
module Rails
module Rack
class Logger < ActiveSupport::LogSubscriber
def call_app(request, env) # :doc:
unless Rails.configuration.logger_exclude.call(request.filtered_path)
instrumenter = ActiveSupport::Notifications.instrumenter
instrumenter.start "request.action_dispatch", request: request
logger.info { started_request_message(request) }
end
status, headers, body = @app.call(env)
body = ::Rack::BodyProxy.new(body) { finish(request) }
[status, headers, body]
rescue Exception
finish(request)
raise
ensure
ActiveSupport::LogSubscriber.flush_all!
end
end
end
end
Then follow with lib/silent_log_subscriber.rb:
require 'active_support/log_subscriber'
require 'action_view/log_subscriber'
require 'action_controller/log_subscriber'
# original class:
# https://github.com/rails/rails/blob/master/actionpack/lib/action_controller/log_subscriber.rb
class SilentLogSubscriber < ActiveSupport::LogSubscriber
def start_processing(event)
return unless logger.info?
payload = event.payload
return if Rails.configuration.logger_exclude.call(payload[:path])
params = payload[:params].except(*ActionController::LogSubscriber::INTERNAL_PARAMS)
format = payload[:format]
format = format.to_s.upcase if format.is_a?(Symbol)
info "Processing by #{payload[:controller]}##{payload[:action]} as #{format}"
info " Parameters: #{params.inspect}" unless params.empty?
end
def process_action(event)
return if Rails.configuration.logger_exclude.call(event.payload[:path])
info do
payload = event.payload
additions = ActionController::Base.log_process_action(payload)
status = payload[:status]
if status.nil? && payload[:exception].present?
exception_class_name = payload[:exception].first
status = ActionDispatch::ExceptionWrapper.status_code_for_exception(exception_class_name)
end
additions << "Allocations: #{event.allocations}" if event.respond_to? :allocations
message = +"Completed #{status} #{Rack::Utils::HTTP_STATUS_CODES[status]} in #{event.duration.round}ms"
message << " (#{additions.join(" | ")})" unless additions.empty?
message << "\n\n" if defined?(Rails.env) && Rails.env.development?
message
end
end
def self.setup
# unsubscribe default processors
ActiveSupport::LogSubscriber.log_subscribers.each do |subscriber|
case subscriber
when ActionView::LogSubscriber
self.unsubscribe(:action_view, subscriber)
when ActionController::LogSubscriber
self.unsubscribe(:action_controller, subscriber)
end
end
end
def self.unsubscribe(component, subscriber)
events = subscriber.public_methods(false).reject { |method| method.to_s == 'call' }
events.each do |event|
ActiveSupport::Notifications.notifier.listeners_for("#{event}.#{component}").each do |listener|
if listener.instance_variable_get('@delegate') == subscriber
ActiveSupport::Notifications.unsubscribe listener
end
end
end
end
end
# subscribe this class
SilentLogSubscriber.attach_to :action_controller
SilentLogSubscriber.setup
Make sure to load modified modules e.g. in config/application.rb after loading rails:
require_relative '../lib/logger'
require_relative '../lib/silent_log_subscriber'
Finally configure excluded paths:
Rails.application.configure do
config.logger_exclude = ->(path) { path == "/health" }
end
As we're modifying core code of Rails it's always good idea to check original classes in Rails version you're using.
If this looks like too many modifications, you can simply use lograge gem which does pretty much the same with few other modifications. Although the Rack::Loggger code has changed since Rails 3, so you might be loosing some functionality.
@neil-stockbridge 's answer not worked for Rails 6.0, I edit some to make it work
# selective_logger.rb
class SelectiveLogger
def initialize app, opts = {}
@app = app
@opts = opts
@opts[:silenced] ||= []
end
def call env
if @opts[:silenced].include?(env['PATH_INFO']) || @opts[:silenced].any? {|silencer| silencer.is_a?( Regexp) && silencer.match( env['PATH_INFO']) }
Rails.logger.silence do
@app.call env
end
else
@app.call env
end
end
end
Test rails app to use it:
# application.rb
config.middleware.swap Rails::Rack::Logger, SelectiveLogger, :silenced => ["/remote/every_minute", %r"^/assets/"]
The following works with Rails 2.3.14:
Make a custom logger that can be silenced:
#selective_logger.rb
require "active_support"
class SelectiveLogger < ActiveSupport::BufferedLogger
attr_accessor :silent
def initialize path_to_log_file
super path_to_log_file
end
def add severity, message = nil, progname = nil, &block
super unless @silent
end
end
Tell Rails to use it:
#environment.rb
config.logger = SelectiveLogger.new config.log_path
Intercept the log output at the beginning of each action and (re)configure the logger depending on whether the action should be silent or not:
#application_controller.rb
# This method is invoked in order to log the lines that begin "Processing..."
# for each new request.
def log_processing
logger.silent = %w"ping time_zone_table".include? params[:action]
super
end
Sprockets-rails gem starting from version 3.1.0 introduces implementation of quiet assets. Unfortunately it's not flexible at this moment, but can be extended easy enough.
Create config/initializers/custom_quiet_assets.rb file:
class CustomQuietAssets < ::Sprockets::Rails::QuietAssets
def initialize(app)
super
@assets_regex = %r(\A/{0,2}#{quiet_paths})
end
def quiet_paths
[
::Rails.application.config.assets.prefix, # remove if you don't need to quiet assets
'/ping',
].join('|')
end
end
Add it to middleware in config/application.rb:
# NOTE: that config.assets.quiet must be set to false (its default value).
initializer :quiet_assets do |app|
app.middleware.insert_before ::Rails::Rack::Logger, CustomQuietAssets
end
Tested with Rails 4.2
Rails 6. I had to put this in config/application.rb, inside my app's class definition:
require 'silencer/logger'
initializer 'my_app_name.silence_health_check_request_logging' do |app|
app.config.middleware.swap(
Rails::Rack::Logger,
Silencer::Logger,
app.config.log_tags,
silence: %w[/my_health_check_path /my_other_health_check_path],
)
end
That leaves the log_tags config intact and modifies the middleware before it gets frozen. I would like to put it in config/initializers/ somewhere tucked away but haven't figured out how to do that yet.
