GrayLogger

GrayLogger is a small logging tool that allows you to simply log anything you want to graylog2 from within your Rack application.

1. Add GrayLogger to your Gemfile

   # in Gemfile
   gem "gray_logger"

2. configure GrayLogger in config/gray_logger.yml

   development:
     host: 127.0.0.1
     port:  12201
     facility: "myapp"
     automatic_logging: true        # flushes all collected fields to graylog after request
     level: 1                       # GELF::INFO

3. if you are using Rails 2.3 please add the following code to an initializer:

begin
  gray_logger_config = YAML.load(File.read(Rails.root.join("config/gray_logger.yml")))[Rails.env]

  host = ENV['YOUR_GRAYLOG_HOST']     || gray_logger_config["host"]
  port = ENV['YOUR_GRAYLOG_PORT']     || gray_logger_config["port"]
  size = ENV['YOUR_GRAYLOG_MAX_SIZE'] || "WAN"

  ::GrayLogger.configure(gray_logger_config)
  ::GrayLogger.proxy.initialize_gray_logger!

  ActionController::Base.send(:include, ::GrayLogger::HelperMethods)

  Rails.configuration.middleware.insert_after Rack::Lock, "Rack::GrayLogger::Middleware"
rescue => e
  Rails.logger.warn("GrayLogger not configured.")
end

4. To install the gray_logger proxy set the logger in your environment file:

require 'gray_logger'
::GrayLogger.proxy.proxied_logger = Logger.new(Rails.root.join("log", Rails.env + ".log"), 3, 50*1024*1024)
config.logger = ::GrayLogger.proxy

In Rails you can use the "gray_logger" method to add new fields to be logged to Graylog2.

You can use buckets to collect fields and send them in one request to GrayLog2:

gray_logger.bucket(:financial_data).account_nr = 123
gray_logger.bucket(:financial_data).iban = 98767
gray_logger.flush_bucket(:financial_data) # sends the collected fields as one log message to GrayLog2 and clears the bucket

When the request is finished all remaining buckets are send to GrayLog2 so you don't have to care if you only want to collect your data.

There is a special bucket that is used for logging possible exceptions and request information. When you are using the Rack::GrayLogger::Proxy the proxy will use this bucket to collect the loglines from the proxied logger. Feel free to add your own fields using:

gray_logger.after_request_log.user_login = current_user.login

Automatic Logging is enabled by default. That means after the request is done GrayLogger will automatically log to GrayLog2. If you don't want this automatic logging disable it by setting automatic_logging to false.

development:
  host: ...
  port:  ...
  facility: ...
  automatic_logging: false