class Logging::Appenders::Syslog

This class provides an Appender that can write to the UNIX syslog daemon.

Public Class Methods

new( name, opts = {} ) click to toggle source

Create an appender that will log messages to the system message logger. The message is then written to the system console, log files, logged-in users, or forwarded to other machines as appropriate. The options that can be used to configure the appender are as follows:

:ident     => identifier string (name is used by default)
:logopt    => options used when opening the connection
:facility  => the syslog facility to use

The parameter :ident is a string that will be prepended to every message. The :logopt argument is a bit field specifying logging options, which is formed by OR'ing one or more of the following values:

LOG_CONS      If syslog() cannot pass the message to syslogd(8) it
              wil attempt to write the message to the console
              ('/dev/console').

LOG_NDELAY    Open the connection to syslogd(8) immediately. Normally
              the open is delayed until the first message is logged.
              Useful for programs that need to manage the order in
              which file descriptors are allocated.

LOG_PERROR    Write the message to standard error output as well to
              the system log.  Not available on Solaris.

LOG_PID       Log the process id with each message: useful for
              identifying instantiations of daemons.

The :facility parameter encodes a default facility to be assigned to all messages that do not have an explicit facility encoded:

LOG_AUTH      The authorization system: login(1), su(1), getty(8),
              etc.

LOG_AUTHPRIV  The same as LOG_AUTH, but logged to a file readable
              only by selected individuals.

LOG_CONSOLE   Messages written to /dev/console by the kernel console
              output driver.

LOG_CRON      The cron daemon: cron(8).

LOG_DAEMON    System daemons, such as routed(8), that are not
              provided for explicitly by other facilities.

LOG_FTP       The file transfer protocol daemons: ftpd(8), tftpd(8).

LOG_KERN      Messages generated by the kernel. These cannot be
              generated by any user processes.

LOG_LPR       The line printer spooling system: lpr(1), lpc(8),
              lpd(8), etc.

LOG_MAIL      The mail system.

LOG_NEWS      The network news system.

LOG_SECURITY  Security subsystems, such as ipfw(4).

LOG_SYSLOG    Messages generated internally by syslogd(8).

LOG_USER      Messages generated by random user processes. This is
              the default facility identifier if none is specified.

LOG_UUCP      The uucp system.

LOG_LOCAL0    Reserved for local use. Similarly for LOG_LOCAL1
              through LOG_LOCAL7.
Calls superclass method Logging::Appender.new
# File lib/logging/appenders/syslog.rb, line 95
def initialize( name, opts = {} )
  @ident = opts.fetch(:ident, name)
  @logopt = Integer(opts.fetch(:logopt, (LOG_PID | LOG_CONS)))
  @facility = Integer(opts.fetch(:facility, LOG_USER))
  @syslog = ::Syslog.open(@ident, @logopt, @facility)

  # provides a mapping from the default Logging levels
  # to the syslog levels
  @map = [LOG_DEBUG, LOG_INFO, LOG_WARNING, LOG_ERR, LOG_CRIT]

  map = opts.fetch(:map, nil)
  self.map = map unless map.nil?

  super
end

Public Instance Methods

close click to toggle source

Closes the connection to the syslog facility.

Calls superclass method Logging::Appender#close
# File lib/logging/appenders/syslog.rb, line 139
def close( footer = true )
  super
  @syslog.close if @syslog.opened?
  self
end
closed? → true or false click to toggle source

Queries the connection to the syslog facility and returns true if the connection is closed.

# File lib/logging/appenders/syslog.rb, line 151
def closed?
  !@syslog.opened?
end
map = { logging_levels → syslog_levels } click to toggle source

Configure the mapping from the Logging levels to the syslog levels. This is needed in order to log events at the proper syslog level.

Without any configuration, the following mapping will be used:

:debug  =>  LOG_DEBUG
:info   =>  LOG_INFO
:warn   =>  LOG_WARNING
:error  =>  LOG_ERR
:fatal  =>  LOG_CRIT
# File lib/logging/appenders/syslog.rb, line 125
def map=( levels )
  map = []
  levels.keys.each do |lvl|
    num = ::Logging.level_num(lvl)
    map[num] = syslog_level_num(levels[lvl])
  end
  @map = map
end
reopen() click to toggle source

Reopen the connection to the underlying logging destination. If the connection is currently closed then it will be opened. If the connection is currently open then it will be closed and immediately opened.

Calls superclass method Logging::Appender#reopen
# File lib/logging/appenders/syslog.rb, line 159
def reopen
  @mutex.synchronize {
    if @syslog.opened?
      flush
      @syslog.close
    end
    @syslog = ::Syslog.open(@ident, @logopt, @facility)
  }
  super
  self
end

Private Instance Methods

syslog_level_num( level ) → integer click to toggle source

Takes the given level as a string, symbol, or integer and returns the corresponding syslog level number.

# File lib/logging/appenders/syslog.rb, line 201
def syslog_level_num( level )
  case level
  when Integer; level
  when String, Symbol
    level = level.to_s.upcase
    self.class.const_get level
  else
    raise ArgumentError, "unkonwn level '#{level}'"
  end
end
write( event ) click to toggle source

Write the given event to the syslog facility. The log event will be processed through the Layout associated with this appender. The message will be logged at the level specified by the event.

# File lib/logging/appenders/syslog.rb, line 181
def write( event )
  pri = LOG_DEBUG
  message = if event.instance_of?(::Logging::LogEvent)
      pri = @map[event.level]
      @layout.format(event)
    else
      event.to_s
    end
  return if message.empty?

  @syslog.log(pri, '%s', message)
  self
end