Class: Lumberjack::SyslogDevice

Inherits:
Device
  • Object
show all
Defined in:
lib/lumberjack/syslog_device.rb

Overview

This Lumberjack device logs output to syslog. There can only be one connection to syslog open at a time. If you use syslog elsewhere in your application, you'll need to pass :close_connection => true to the constructor. Otherwise, the connection will be kept open between write calls.

Constant Summary collapse

VERSION = 
::File.read(::File.join(__dir__, "..", "..", "VERSION")).strip.freeze
SEVERITY_MAP =

Mapping of Lumberjack severity levels to syslog priority levels

{
  Severity::TRACE => Syslog::LOG_DEBUG,
  Severity::DEBUG => Syslog::LOG_DEBUG,
  Severity::INFO => Syslog::LOG_INFO,
  Severity::WARN => Syslog::LOG_WARNING,
  Severity::ERROR => Syslog::LOG_ERR,
  Severity::FATAL => Syslog::LOG_CRIT,
  Severity::UNKNOWN => Syslog::LOG_ALERT
}
PERCENT =

Literal percent character

"%"
ESCAPED_PERCENT =

Escaped percent character for syslog format strings

"%%"
DEFAULT_TEMPLATE =

Default template for formatting log messages

"{{message}} {{attributes}}"
DEFAULT_ATTRIBUTE_FORMAT =

Default format for rendering log entry attributes

"[%s:%s]"
@@lock = 
Mutex.new

Instance Method Summary collapse

Constructor Details

#initialize(options = {}) ⇒ SyslogDevice

Create a new SyslogDevice. The options control how messages are written to syslog.

The template can be specified using the :template option. This can either be a Proc or a string that will compile into a Template object. If the template is a Proc, it should accept an LogEntry as its only argument and output a string. If the template is a template string, it will be used to create a Template. The default template is {{message}} {{attributes}}.

The :close_connection option can be used to specify that the connection to syslog should be closed after every write call. This will slow down performance, but will allow you to use syslog elsewhere in your application.

The :options option will pass through options to syslog. The default is Syslog::LOG_PID | Syslog::LOG_CONS. Available values for the bit map are:

  • Syslog::LOG_CONS - Write directly to system console if there is an error while sending to system logger.
  • Syslog::LOG_NDELAY - Open the connection immediately (normally, the connection is opened when the first message is logged).
  • Syslog::LOG_NOWAIT - Don't wait for child processes that may have been created while logging the message.
  • Syslog::LOG_ODELAY - The converse of LOG_NDELAY; opening of the connection is delayed.
  • Syslog::LOG_PERROR - Print to stderr as well.
  • Syslog::LOG_PID - Include PID with each message.

The :facility option will pass through a facility to syslog. Available values are

  • Syslog::LOG_AUTH
  • Syslog::LOG_AUTHPRIV
  • Syslog::LOG_CRON
  • Syslog::LOG_DAEMON
  • Syslog::LOG_FTP
  • Syslog::LOG_KERN
  • Syslog::LOG_LOCAL0 through Syslog::LOG_LOCAL7
  • Syslog::LOG_LPR
  • Syslog::LOG_MAIL
  • Syslog::LOG_NEWS
  • Syslog::LOG_SYSLOG
  • Syslog::LOG_USER (default)
  • Syslog::LOG_UUCP


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# File 'lib/lumberjack/syslog_device.rb', line 76

def initialize(options = {})
  @template = options[:template] || DEFAULT_TEMPLATE
  attribute_format = options[:attribute_format] || DEFAULT_ATTRIBUTE_FORMAT
  @template = Template.new(@template, attribute_format: attribute_format) if @template.is_a?(String)

  @syslog_options = options[:options] || (Syslog::LOG_PID | Syslog::LOG_CONS)
  # Syslog substitutes LOG_USER for a nil facility; normalize here so the
  # connection reuse check in open_syslog matches what syslog reports back.
  @syslog_facility = options[:facility] || Syslog::LOG_USER
  @close_connection = options[:close_connection]
end

Instance Method Details

#close ⇒ void

This method returns an undefined value.

Close the syslog connection.



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# File 'lib/lumberjack/syslog_device.rb', line 108

def close
  flush
  @@lock.synchronize do
    syslog_implementation.close if syslog_implementation.opened?
  end
end

#write(entry) ⇒ void

This method returns an undefined value.

Write a log entry to syslog.

Parameters:

  • entry (Lumberjack::LogEntry) —

    the log entry to write



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# File 'lib/lumberjack/syslog_device.rb', line 92

def write(entry)
  message = @template.call(entry).to_s.chomp.gsub(PERCENT, ESCAPED_PERCENT)
  severity = SEVERITY_MAP[entry.severity] || Syslog::LOG_ALERT
  @@lock.synchronize do
    syslog = open_syslog(entry.progname)
    begin
      syslog.log(severity, message)
    ensure
      syslog.close if @close_connection
    end
  end
end