问题
Is this outdated? http://guides.rubyonrails.org/debugging_rails_applications.html I am following it step by step,
And in part '2.1 What is the Logger?'
It says how to create a custom logger.
1) You can specify an alternative logger in your environment.rb or any environment file:
Rails.logger = Logger.new(STDOUT)
Rails.logger = Log4r::Logger.new("Application Log")
I put this code in my environment.rb file and I get this:
uninitialized constant Log4r (NameError)
..then it says 'Or in the Initializer section, add any of the following:'
config.logger = Logger.new(STDOUT)
config.logger = Log4r::Logger.new("Application Log")
I dont have an initializer section in my environment.rb file! I get the same error!
It says 'You can also substitute another logger such as Log4r if you wish.' Why would somebody want to substitute an existing logger?
I removed Rails.logger = Log4r::Logger.new("Application Log") from the environment.rb file.
It seems to be working, but I was expecting a file being created in the log/ directory but nothing. Here is my enviroment.rb file:
# Load the rails application
require File.expand_path('../application', __FILE__)
Rails.logger = Logger.new('Application Log')
# Initialize the rails application
MyApp::Application.initialize!
help? Some explanation please?
回答1:
You can set the Rails logger globally with:
Rails.logger = ...
or you can put it into an environment file, e.g. in config/environments/development.rb
MyApp::Application.configure do
config.logger = ...
end
Next, Log4r is a separate gem that does not come with Rails. If you want to use it, add it to your Gemfile:
gem "log4r", "~> 1.1.10"
Why would somebody want to substitute an existing logger?
Because loggers have a different set of features. You might want to use a custom logger to upload the logs to an external service, process it etc.
回答2:
You need to require log4r in application.rb. I am assuming you have installed the gem. then in application.rb
require 'log4r'
来源：https://stackoverflow.com/questions/14400831/create-a-custom-rails-logger