Module: ImprovedLogging

Defined in:
lib/improved_logging/improved_logging.rb,
lib/improved_logging/version.rb

Overview

This module, when included into ActiveSupport::BufferedLogger, improves the logging format. See the README file for more info.

This is distributed under a Creative Commons “Attribution-Share Alike” license: for details see: creativecommons.org/licenses/by-sa/3.0/

Constant Summary collapse

VERSION = 
'1.0.2'
LENGTH = 
::ActiveSupport::BufferedLogger::Severity.constants.map{|c| c.to_s.length}.max
@@verbose =

These are configurable, put something like the following in an initializer:

ImprovedLogging.verbose = false

defined?(::Rails) ? ::Rails.env != "development" : false
@@full_hostname = 
get_hostname
@@hostname_maxlen = 
10
@@custom = 
nil
@@pid =

These are not configurable

$$
@@line_prefix = 
format_line_prefix

Class Method Summary collapse

Instance Method Summary collapse

Class Method Details

.custom=(string) ⇒ Object 



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# File 'lib/improved_logging/improved_logging.rb', line 60

def self.custom=(string)
  @@custom = string
  @@line_prefix = format_line_prefix
end

.format_line_prefix ⇒ Object 



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# File 'lib/improved_logging/improved_logging.rb', line 70

def self.format_line_prefix
  if @@full_hostname.length < @@hostname_maxlen
    hostname = @@full_hostname
  else
    hostname = @@full_hostname[-(@@hostname_maxlen)..-1]
  end
  
  line_prefix = sprintf("%1$*2$s", "#{hostname}.#{@@pid}  ", -(7 + hostname.length))
  line_prefix = "#{@@custom}  #{line_prefix}" if @@custom
  return line_prefix
end

.get_hostname ⇒ Object 



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# File 'lib/improved_logging/improved_logging.rb', line 82

def self.get_hostname
  `hostname -s`.strip
end

.hostname_maxlen=(integer) ⇒ Object 



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# File 'lib/improved_logging/improved_logging.rb', line 65

def self.hostname_maxlen=(integer)
  @@hostname_maxlen = integer
  @@line_prefix = format_line_prefix
end

.included(base) ⇒ Object 



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# File 'lib/improved_logging/improved_logging.rb', line 11

def self.included(base)
  base.class_eval do
    alias_method_chain :add, :extra_info
    alias_method_chain :error, :exception_param
    alias_method_chain :warn, :exception_param
  end
  
  # Get the length to format the output so that the pid column lines up.
  # The severity levels probably won't change but this avoids hard-coding
  # them anyway, just in case.
  # Most of this is done with class_eval so it should only be done once 
  # while the class is being loaded.
  if_stmts = ""
  for c in ::ActiveSupport::BufferedLogger::Severity.constants
    if_stmts += <<-EOT
      if severity == #{c}
        severity_name = sprintf("%1$*2$s", "#{c}", #{LENGTH * -1})
        use_colour = false
        if ::Rails.version.to_i >= 3
          use_colour = true if ::ActiveSupport::LogSubscriber.colorize_logging
        else
          use_colour = true if defined?(::ActiveRecord) && ::ActiveRecord::Base.colorize_logging
        end
        if use_colour
          if severity == INFO
            severity_name = "\033[32m" + severity_name + "\033[0m"
          elsif severity == WARN
            severity_name = "\033[33m" + severity_name + "\033[0m"
          elsif severity == ERROR || severity == FATAL
            severity_name = "\033[31m" + severity_name + "\033[0m"
          end
        end
        return severity_name
      end
    EOT
  end
  base.class_eval <<-EOT, __FILE__, __LINE__
    def self.severity_name(severity)
      #{if_stmts}
      return "UNKNOWN"
    end
  EOT
end

.verbose=(boolean) ⇒ Object 



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# File 'lib/improved_logging/improved_logging.rb', line 56

def self.verbose=(boolean)
  @@verbose = boolean
end

Instance Method Details

#add_with_extra_info(severity, message = nil, progname = nil, &block) ⇒ Object 



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# File 'lib/improved_logging/improved_logging.rb', line 109

def add_with_extra_info(severity, message = nil, progname = nil, &block)
  update_pid
  time = @@verbose ? "#{Time.new.strftime('%H:%M:%S')}  " : ""
  message = "#{time}#{::ActiveSupport::BufferedLogger.severity_name(severity)}  #{message}"
  
  # Make sure every line has the PID and hostname and custom string 
  # so we can use grep to isolate output from one process or server.
  # gsub works even when the output contains "\n", though there's
  # probably a small performance cost.
  message = message.gsub(/^/, @@line_prefix) if @@verbose
  
  add_without_extra_info(severity, message, progname, &block)
end

#error_with_exception_param(message = '', exception = nil) ⇒ Object

add an optional second parameter to the error & warn methods to allow a stack trace:



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# File 'lib/improved_logging/improved_logging.rb', line 126

def error_with_exception_param(message = '', exception = nil)
  message = yield if block_given?
  message += "\n#{exception.inspect}\n#{exception.backtrace.join("\n")}" if exception
  error_without_exception_param(message)
end

#update_pid ⇒ Object

the cached pid can be wrong after a fork(), this checks if it has changed and re-caches the line_prefix



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# File 'lib/improved_logging/improved_logging.rb', line 102

def update_pid
  if @@pid != $$
    @@pid = $$
    @@line_prefix = ImprovedLogging.format_line_prefix
  end
end

#warn_with_exception_param(message = '', exception = nil) ⇒ Object 



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# File 'lib/improved_logging/improved_logging.rb', line 132

def warn_with_exception_param(message = '', exception = nil)
  message = yield if block_given?
  message += "\n#{exception.inspect}\n#{exception.backtrace.join("\n")}" if exception
  warn_without_exception_param(message)
end