Syslog::Logger

Class

Syslog::Logger is a Logger work-alike that logs via syslog instead of to a file. You can use Syslog::Logger to aggregate logs between multiple machines.

By default, Syslog::Logger uses the program name ‘ruby’, but this can be changed via the first argument to Syslog::Logger.new.

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

Example

The following will log to syslogd on your local machine:

require 'syslog/logger'

log = Syslog::Logger.new 'my_program'
log.info 'this line will be logged via syslog(3)'

Also the facility may be set to specify the facility level which will be used:

log.info 'this line will be logged using Syslog default facility level'

log_local1 = Syslog::Logger.new 'my_program', Syslog::LOG_LOCAL1
log_local1.info 'this line will be logged using local1 facility level'

You may need to perform some syslog.conf setup first. For a BSD machine add the following lines to /etc/syslog.conf:

!my_program
*.*                                             /var/log/my_program.log

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

If you wish to have logs automatically roll over and archive, see the newsyslog.conf(5) and newsyslog(8) man pages.

Constants

VERSION

The version of Syslog::Logger you are using.

LEVEL_MAP

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

Messages from Ruby applications are not considered as critical as messages from other system daemons using syslog(3), so most messages are reduced by one level. For example, a fatal message for Ruby’s Logger is considered an error for syslog(3).

Attributes

level

Read & Write

Log level for Logger compatibility.

formatter

Read & Write

Logging formatter, as a Proc that will take four arguments and return the formatted message. The arguments are:

severity: The Severity of the log message.
time: A Time instance representing when the message was logged.
progname: The progname configured, or passed to the logger method.
msg: The Object the user passed to the log message; not necessarily a String.

The block should return an Object that can be written to the logging device via write. The default formatter is used when no formatter is set.

facility

Read & Write

The facility argument is used to specify what type of program is logging the message.

Class Methods

make_methods(meth)

ext/syslog/lib/syslog/logger.rb View on GitHub

          
            # File tmp/rubies/ruby-2.5.9/ext/syslog/lib/syslog/logger.rb, line 107
  def self.make_methods meth
    level = ::Logger.const_get(meth.upcase)
    eval <<-EOM, nil, __FILE__, __LINE__ + 1
      def #{meth}(message = nil, &block)
        add(#{level}, message, &block)
      end

      def #{meth}?
        @level <= #{level}
      end
    EOM
  end

Builds a methods for level meth.

new(program_name = 'ruby', facility = nil)

ext/syslog/lib/syslog/logger.rb View on GitHub

          
            # File tmp/rubies/ruby-2.5.9/ext/syslog/lib/syslog/logger.rb, line 191
def initialize program_name = 'ruby', facility = nil
  @level = ::Logger::DEBUG
  @formatter = Formatter.new

  @@syslog ||= Syslog.open(program_name)

  @facility = (facility || @@syslog.facility)
end

Fills in variables for Logger compatibility. If this is the first instance of Syslog::Logger, program_name may be set to change the logged program name. The facility may be set to specify the facility level which will be used.

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

syslog

ext/syslog/lib/syslog/logger.rb View on GitHub

          
            # File tmp/rubies/ruby-2.5.9/ext/syslog/lib/syslog/logger.rb, line 93
def self.syslog
  @@syslog
end

Returns the internal Syslog object that is initialized when the first instance is created.

syslog=(syslog)

ext/syslog/lib/syslog/logger.rb View on GitHub

          
            # File tmp/rubies/ruby-2.5.9/ext/syslog/lib/syslog/logger.rb, line 100
def self.syslog= syslog
  @@syslog = syslog
end

Specifies the internal Syslog object to be used.

Instance Methods

add(severity, message = nil, progname = nil, &block)

ext/syslog/lib/syslog/logger.rb View on GitHub

          
            # File tmp/rubies/ruby-2.5.9/ext/syslog/lib/syslog/logger.rb, line 203
def add severity, message = nil, progname = nil, &block
  severity ||= ::Logger::UNKNOWN
  @level <= severity and
    @@syslog.log( (LEVEL_MAP[severity] | @facility), '%s', formatter.call(severity, Time.now, progname, (message || block.call)) )
  true
end

Almost duplicates Logger#add. progname is ignored.

debug

ext/syslog/lib/syslog/logger.rb View on GitHub

          
            # File tmp/rubies/ruby-2.5.9/ext/syslog/lib/syslog/logger.rb, line 151

Logs a message at the debug (syslog debug) log level, or logs the message returned from the block.

error

ext/syslog/lib/syslog/logger.rb View on GitHub

          
            # File tmp/rubies/ruby-2.5.9/ext/syslog/lib/syslog/logger.rb, line 133

Logs a message at the error (syslog warning) log level, or logs the message returned from the block.

fatal

ext/syslog/lib/syslog/logger.rb View on GitHub

          
            # File tmp/rubies/ruby-2.5.9/ext/syslog/lib/syslog/logger.rb, line 127

Logs a message at the fatal (syslog err) log level, or logs the message returned from the block.

info

ext/syslog/lib/syslog/logger.rb View on GitHub

          
            # File tmp/rubies/ruby-2.5.9/ext/syslog/lib/syslog/logger.rb, line 145

Logs a message at the info (syslog info) log level, or logs the message returned from the block.

unknown

ext/syslog/lib/syslog/logger.rb View on GitHub

          
            # File tmp/rubies/ruby-2.5.9/ext/syslog/lib/syslog/logger.rb, line 121

Logs a message at the unknown (syslog alert) log level, or logs the message returned from the block.

warn

ext/syslog/lib/syslog/logger.rb View on GitHub

          
            # File tmp/rubies/ruby-2.5.9/ext/syslog/lib/syslog/logger.rb, line 139

Logs a message at the warn (syslog notice) log level, or logs the message returned from the block.