How can I disable logging of asset pipeline (sprockets) messages in Ruby on Rails 3.1?

Place the following code in config/initializers/quiet_assets.rb

if Rails.env.development?
  Rails.application.assets.try(:logger=, Logger.new('/dev/null'))
  Rails::Rack::Logger.class_eval do
    def call_with_quiet_assets(env)
      previous_level = Rails.logger.level
      Rails.logger.level = Logger::ERROR if env['PATH_INFO'] =~ %r{^/assets/}
      call_without_quiet_assets(env)
    ensure
      Rails.logger.level = previous_level
    end
    alias_method_chain :call, :quiet_assets
  end
end

Updated: It now works for Ruby on Rails 3.2 too (previous attempt fixes before_dispatch, and now we're going for the root rack call instead)

Update: A proper Rack middleware solution (instead of fragile alias_method_chain) from @macournoyer https://github.com/rails/rails/issues/2639#issuecomment-6591735

Take a look at https://github.com/evrone/quiet_assets and just include it into your Gem file.

For the lazy: gem 'quiet_assets', group: :development

For Ruby on Rails 3.2, add config.assets.logger = false to your development environment configuration file, typically found at config/environments/development.rb. See #4512.

Two things are enough:

config.assets.debug = false in config/enviroments/development.rb rake assets:precompile. See comment by @oma below; this is not needed

That's all!

Eventually, it will be config.assets.logger = nil, but that part is currently stubbed on master (not done yet).

I know it's an ugly and temporary solution, but I use this:

tail -f log/development.log | grep -vE 'asset'

Many people are confused about the use of config.assets.logger = false. Here is what it does and what it doesn't do.

According the source documentation:

Setting config.assets.logger to false will turn off served assets logging.

However this probably is not what you think it is. It only disables sprocket 'serving' logs, not Ruby on Rails actionpack request logs. The Ruby on Rails maintainer explains this clearly here: https://github.com/rails/rails/issues/4569#issuecomment-3594500

Taking example from the link, logs like this are disabled:

Served asset /jquery.isotope.js - 304 Not Modified (0ms)

But logs like this are not

Started GET "/assets/jquery.isotope.js?body=1" for 127.0.0.1 at 2012-01-20 23:16:46 -0500

config.assets.quiet = true

This is the latest way to go.

Use:

Rails.application.assets.logger = Logger.new(RUBY_PLATFORM =~ /(win|w)32$/ ? "NUL" : "/dev/null")
Rails::Rack::Logger.class_eval do
  def call_with_quiet_assets(env)
    previous_level = Rails.logger.level
    Rails.logger.level = Logger::ERROR if env['PATH_INFO'].index("/assets/") == 0
    call_without_quiet_assets(env).tap do
      Rails.logger.level = previous_level
    end
  end
  alias_method_chain :call, :quiet_assets
end

It's the same code choonkeat added. I just included it to work under Windows as well.

In file development.rb in config/environments you'll find the line config.assets.debug = true.

Switch that to false and most of the asset load output will be gone. On my system only the two requests, for application.css and .js, remain.

In file config/environments/development.rb please add:

config.assets.debug = false

config.assets.logger = false

Lograge for the win - it kills Ruby on Rails' annoying logger defaults out of the box (e.g. logging assets, logging partial rendering) and is customizable if you want to add/remove specific items.

The previously mentioned linked solution helps:

https://github.com/evrone/quiet_assets

Also as below, it's working fine for me:

3.1 (only) (3.2 breaks before_dipatch)

app\config\initializers\quiet_assets.rb

Rails.application.assets.logger = Logger.new('/dev/null')
Rails::Rack::Logger.class_eval do
  def before_dispatch_with_quiet_assets(env)
    before_dispatch_without_quiet_assets(env) unless env['PATH_INFO'].index("/assets/") == 0
  end
  alias_method_chain :before_dispatch, :quiet_assets
end
3.2 Rails - Rack root tap approach
app\config\initializers\quiet_assets.rb

Rails.application.assets.logger = Logger.new('/dev/null')
Rails::Rack::Logger.class_eval do
  def call_with_quiet_assets(env)
    previous_level = Rails.logger.level
    Rails.logger.level = Logger::ERROR if env['PATH_INFO'].index("/assets/") == 0
    call_without_quiet_assets(env).tap do
      Rails.logger.level = previous_level
    end
  end
  alias_method_chain :call, :quiet_assets
end

In config/environments add config.log_level = :error to the .rb files you want to change. This will change the log settings to error only.