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One-line detailed logging for Rails 3 (ActiveSupport::Notifications) and later
# Outputs this at warn log level:
# GET /path 200 OK BlahController#action HTML 938.2 (DB 11.8, View 719.7) {params} {optional params from flash[:log]}
# Save as config/initializers/oneline_detailed_logging.rb. Consider
# decreasing the log level from "info" to "warn" (in production.rb) so
# the one-line log message replaces the standard request logs.
# override process_action to add 2 things to the payload:
# - remote IP
# - an optional stash which is available to subscribers. Basically, flash[:log].inspect will be logged.
# 3.0:
# 3.1:
ActionController::Instrumentation.send(:define_method, "process_action") do |arg|
raw_payload = {
:controller =>,
:action => self.action_name,
:params => request.filtered_parameters,
:formats =>,
:method => request.method,
:path => (request.fullpath rescue "unknown"),
:ip => request.remote_ip,
:stash => request.session['flash'] && request.session['flash'][:log]
ActiveSupport::Notifications.instrument("start_processing.action_controller", raw_payload.dup)
ActiveSupport::Notifications.instrument("process_action.action_controller", raw_payload) do |payload|
result = super(arg)
payload[:status] = response.status
ActiveSupport::Notifications.subscribe "process_action.action_controller" do |name, start, finish, id, payload|
# borrows from
params = payload[:params].except('controller', 'action', 'format', '_method', 'only_path')
format = payload[:formats].first.to_s.upcase
duration = (finish-start)*1000
status = payload[:status]
if status.nil? && payload[:exception].present?
# 3.1:
status = Rack::Utils.status_code(ActionDispatch::ShowExceptions.rescue_responses[payload[:exception].first]) rescue nil
m = "%s %s %s %s %s %s\#%s %s %.1f (DB %.1f, View %.1f) %s %s" % [
payload[:ip], payload[:method], payload[:path],
status, Rack::Utils::HTTP_STATUS_CODES[status],
payload[:controller], payload[:action], format,
duration || 0, payload[:db_runtime] || 0, payload[:view_runtime] || 0,
params.inspect, payload[:stash].try(:inspect) || {}.inspect ]

jelder commented May 14, 2013

Hi Troy,

This might need an update for Rails 3.2 and beyond:

DEPRECATION WARNING: ActionDispatch::ShowExceptions.rescue_responses is deprecated. Please configure your exceptions using a railtie or in your application config instead.

gnomet commented Jun 3, 2013

I picked the solution for that line from the fork at and it seems to remove the deprecation warning.

As an FYI if you're using Rails 4 on Heroku this works, but setting the log_level to :warn won't take effect due to the rails_stdout_logging gem. So you'll see the old logs, and the compressed logs. This is because the gem is not respecting any config/environment/production.rb setting. The issue has been logged on github and a temp workaround is to set the LOG_LEVEL in the heroku config settings

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