Class: SyslogLogger

Inherits:
Object
  • Object
show all
Defined in:
lib/syslog_logger.rb

Overview

SyslogLogger is a Logger work-alike that logs via syslog instead of to a file. You can add SyslogLogger to your Rails production environment to aggregate logs between multiple machines.

By default, SyslogLogger uses the program name ‘rails’, but this can be changed via the first argument to SyslogLogger.new.

NOTE! You can only set the SyslogLogger program name when you initialize SyslogLogger for the first time. This is a limitation of the way SyslogLogger uses syslog (and in some ways, a limitation of the way syslog(3) works). Attempts to change SyslogLogger’s program name after the first initialization will be ignored.

Sample usage with Rails

config/environment/production.rb

Add the following lines:

require 'syslog_logger'
RAILS_DEFAULT_LOGGER = SyslogLogger.new

config/environment.rb

In 0.10.0, change this line:

RAILS_DEFAULT_LOGGER = Logger.new("#{RAILS_ROOT}/log/#{RAILS_ENV}.log")

to:

RAILS_DEFAULT_LOGGER ||= Logger.new("#{RAILS_ROOT}/log/#{RAILS_ENV}.log")

Other versions of Rails should have a similar change.

BSD syslog setup

/etc/syslog.conf

Add the following lines:

!rails
*.*                                             /var/log/production.log

Then touch /var/log/production.log and signal syslogd with a HUP (killall -HUP syslogd, on FreeBSD).

/etc/newsyslog.conf

Add the following line:

/var/log/production.log                 640  7     *    @T00  Z

This creates a log file that is rotated every day at midnight, gzip’d, then kept for 7 days. Consult newsyslog.conf(5) for more details.

syslog-ng setup

syslog-ng.conf

destination rails_log { file(“/var/log/production.log”); }; filter f_rails { program(“rails.*”); }; log { source(src); filter(f_rails); destination(rails_log); };

Starting

Now restart your Rails app. Your production logs should now be showing up in /var/log/production.log. If you have mulitple machines, you can log them all to a central machine with remote syslog logging for analysis. Consult your syslogd(8) manpage for further details.

Constant Summary collapse

VERSION =

The version of SyslogLogger you are using.

'1.4.0'
LOGGER_MAP =

Maps Logger warning types to syslog(3) warning types.

{
  :unknown => :alert,
  :fatal   => :err,
  :error   => :warning,
  :warn    => :notice,
  :info    => :info,
  :debug   => :debug,
}
LOGGER_LEVEL_MAP =

Maps Logger log levels to their values so we can silence.

{}
LEVEL_LOGGER_MAP =

Maps Logger log level values to syslog log levels.

{}

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(program_name = 'rails') ⇒ SyslogLogger

Fills in variables for Logger compatibility. If this is the first instance of SyslogLogger, program_name may be set to change the logged program name.

Due to the way syslog works, only one program name may be chosen.



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# File 'lib/syslog_logger.rb', line 145

def initialize(program_name = 'rails')
  @level = Logger::DEBUG

  return if defined? SYSLOG
  self.class.const_set :SYSLOG, Syslog.open(program_name)
end

Instance Attribute Details

#level ⇒ Object

Log level for Logger compatibility.



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# File 'lib/syslog_logger.rb', line 136

def level
  @level
end

Class Method Details

.make_methods(meth) ⇒ Object

Builds a methods for level meth.



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# File 'lib/syslog_logger.rb', line 115

def self.make_methods(meth)
  eval <<-EOM, nil, __FILE__, __LINE__ + 1
    def #{meth}(message = nil)
      return true if #{LOGGER_LEVEL_MAP[meth]} < @level
      SYSLOG.#{LOGGER_MAP[meth]} clean(message || yield)
      return true
    end

    def #{meth}?
      @level <= Logger::#{meth.to_s.upcase}
    end
  EOM
end

Instance Method Details

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

Almost duplicates Logger#add. progname is ignored.



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# File 'lib/syslog_logger.rb', line 155

def add(severity, message = nil, progname = nil, &block)
  severity ||= Logger::UNKNOWN
  return true if severity < @level
  message = clean(message || block.call)
  SYSLOG.send LEVEL_LOGGER_MAP[severity], clean(message)
  return true
end

#silence(temporary_level = Logger::ERROR) ⇒ Object

Allows messages of a particular log level to be ignored temporarily.

Can you say “Broken Windows”?



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# File 'lib/syslog_logger.rb', line 168

def silence(temporary_level = Logger::ERROR)
  old_logger_level = @level
  @level = temporary_level
  yield
ensure
  @level = old_logger_level
end