Class: SemanticLogger::Appender::Syslog

Inherits:
Subscriber show all
Defined in:
lib/semantic_logger/appender/syslog.rb

Instance Attribute Summary collapse

Attributes inherited from Subscriber

#application, #formatter, #host, #logger, #metrics

Attributes inherited from Base

#filter, #name

Instance Method Summary collapse

Methods inherited from Subscriber

#close, #level, #should_log?

Methods inherited from Base

#backtrace, #fast_tag, #level, #level=, #measure, #payload, #pop_tags, #push_tags, #should_log?, #silence, #tagged, #tags, #with_payload

Constructor Details

#initialize(url: 'syslog://localhost', facility: ::Syslog::LOG_USER, level_map: SemanticLogger::Formatters::Syslog::LevelMap.new, options: ::Syslog::LOG_PID | ::Syslog::LOG_CONS, tcp_client: {}, **args, &block) ⇒ Syslog

Create a Syslog appender instance.

Parameters

url: [String]
  Default: 'syslog://localhost'
  For writing logs to a remote syslog server
  URL of server: protocol://host:port
  Uses port 514 by default for TCP and UDP.
  local syslog example:          'syslog://localhost'
  TCP example with default port: 'tcp://logger'
  TCP example with custom port:  'tcp://logger:8514'
  UDP example with default port: 'udp://logger'
  UDP example with custom port:  'udp://logger:8514'
  When using the :syslog protocol, logs will always be sent to the localhost syslog

host: [String]
  Host name to provide to the remote syslog.
  Default: SemanticLogger.host

tcp_client: [Hash]
  Default: {}
  Only used with the TCP protocol.
  Specify custom parameters to pass into Net::TCPClient.new
  For a list of options see the net_tcp_client documentation:
    https://github.com/rocketjob/net_tcp_client/blob/master/lib/net/tcp_client/tcp_client.rb

level: [:trace | :debug | :info | :warn | :error | :fatal]
  Override the log level for this appender.
  Default: SemanticLogger.default_level

filter: [Regexp|Proc]
  RegExp: Only include log messages where the class name matches the supplied.
  regular expression. All other messages will be ignored.
  Proc: Only include log messages where the supplied Proc returns true
        The Proc must return true or false.

application: [String]
  Identity of the program.
  Default: SemanticLogger.application

options: [Integer]
  Default: ::Syslog::LOG_PID | ::Syslog::LOG_CONS
  Any of the following (options can be logically OR'd together)
    ::Syslog::LOG_CONS
    ::Syslog::LOG_NDELAY
    ::Syslog::LOG_NOWAIT
    ::Syslog::LOG_ODELAY
    ::Syslog::LOG_PERROR
    ::Syslog::LOG_PID
 Note:
   - Only applicable when logging to a local syslog instance.
     I.e. When `url: 'syslog://localhost'`

facility: [Integer]
  Default: ::Syslog::LOG_USER
  Type of program (can be logically OR'd together)
    ::Syslog::LOG_AUTH
    ::Syslog::LOG_AUTHPRIV
    ::Syslog::LOG_CONSOLE
    ::Syslog::LOG_CRON
    ::Syslog::LOG_DAEMON
    ::Syslog::LOG_FTP
    ::Syslog::LOG_KERN
    ::Syslog::LOG_LRP
    ::Syslog::LOG_MAIL
    ::Syslog::LOG_NEWS
    ::Syslog::LOG_NTP
    ::Syslog::LOG_SECURITY
    ::Syslog::LOG_SYSLOG
    ::Syslog::LOG_USER
    ::Syslog::LOG_UUCP
    ::Syslog::LOG_LOCAL0
    ::Syslog::LOG_LOCAL1
    ::Syslog::LOG_LOCAL2
    ::Syslog::LOG_LOCAL3
    ::Syslog::LOG_LOCAL4
    ::Syslog::LOG_LOCAL5
    ::Syslog::LOG_LOCAL6
    ::Syslog::LOG_LOCAL7

level_map: [Hash | SemanticLogger::Formatters::Syslog::LevelMap]
  Supply a custom map of SemanticLogger levels to syslog levels.

Example:
  # Change the warn level to LOG_NOTICE level instead of a the default of LOG_WARNING.
  SemanticLogger.add_appender(appender: :syslog, level_map: {warn: ::Syslog::LOG_NOTICE})



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# File 'lib/semantic_logger/appender/syslog.rb', line 122

def initialize(url: 'syslog://localhost',
               facility: ::Syslog::LOG_USER,
               level_map: SemanticLogger::Formatters::Syslog::LevelMap.new,
               options: ::Syslog::LOG_PID | ::Syslog::LOG_CONS,
               tcp_client: {},
               **args,
               &block)

  @options            = options
  @facility           = facility
  @level_map          = level_map
  @url                = url
  uri                 = URI(@url)
  @server             = uri.host || 'localhost'
  @protocol           = (uri.scheme || :syslog).to_sym
  @port               = uri.port || 514
  @server             = 'localhost' if @protocol == :syslog
  @tcp_client_options = tcp_client

  raise "Unknown protocol #{@protocol}!" unless %i[syslog tcp udp].include?(@protocol)

  # The syslog_protocol gem is required when logging over TCP or UDP.
  if %i[tcp udp].include?(@protocol)
    begin
      require 'syslog_protocol'
    rescue LoadError
      raise 'Missing gem: syslog_protocol. This gem is required when logging over TCP or UDP. To fix this error: gem install syslog_protocol'
    end

    # The net_tcp_client gem is required when logging over TCP.
    if protocol == :tcp
      begin
        require 'net/tcp_client'
      rescue LoadError
        raise 'Missing gem: net_tcp_client. This gem is required when logging over TCP. To fix this error: gem install net_tcp_client'
      end
    end
  end

  super(**args, &block)
  reopen
end

Instance Attribute Details

#facility ⇒ Object (readonly)

Returns the value of attribute facility.



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# File 'lib/semantic_logger/appender/syslog.rb', line 34

def facility
  @facility
end

#level_map ⇒ Object (readonly)

Returns the value of attribute level_map.



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# File 'lib/semantic_logger/appender/syslog.rb', line 34

def level_map
  @level_map
end

#options ⇒ Object (readonly)

Returns the value of attribute options.



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# File 'lib/semantic_logger/appender/syslog.rb', line 34

def options
  @options
end

#port ⇒ Object (readonly)

Returns the value of attribute port.



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# File 'lib/semantic_logger/appender/syslog.rb', line 34

def port
  @port
end

#protocol ⇒ Object (readonly)

Returns the value of attribute protocol.



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# File 'lib/semantic_logger/appender/syslog.rb', line 34

def protocol
  @protocol
end

#remote_syslog ⇒ Object (readonly)

Returns the value of attribute remote_syslog.



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# File 'lib/semantic_logger/appender/syslog.rb', line 34

def remote_syslog
  @remote_syslog
end

#server ⇒ Object (readonly)

Returns the value of attribute server.



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# File 'lib/semantic_logger/appender/syslog.rb', line 34

def server
  @server
end

#url ⇒ Object (readonly)

Returns the value of attribute url.



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# File 'lib/semantic_logger/appender/syslog.rb', line 34

def url
  @url
end

Instance Method Details

#default_formatter ⇒ Object

Returns [SemanticLogger::Formatters::Base] default formatter for this Appender depending on the protocal selected



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# File 'lib/semantic_logger/appender/syslog.rb', line 207

def default_formatter
  if protocol == :syslog
    # Format is text output without the time
    SemanticLogger::Formatters::Default.new(time_format: nil)
  else
    SemanticLogger::Formatters::Syslog.new(facility: facility, level_map: level_map)
  end
end

#flush ⇒ Object

Flush is called by the semantic_logger during shutdown.



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# File 'lib/semantic_logger/appender/syslog.rb', line 202

def flush
  @remote_syslog.flush if @remote_syslog&.respond_to?(:flush)
end

#log(log) ⇒ Object

Write the log using the specified protocol and server.



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# File 'lib/semantic_logger/appender/syslog.rb', line 185

def log(log)
  case @protocol
  when :syslog
    # Since the Ruby Syslog API supports sprintf format strings, double up all existing '%'
    message = formatter.call(log, self).gsub '%', '%%'
    ::Syslog.log @level_map[log.level], message
  when :tcp
    @remote_syslog.retry_on_connection_failure { @remote_syslog.write("#{formatter.call(log, self)}\r\n") }
  when :udp
    @remote_syslog.send(formatter.call(log, self), 0, @server, @port)
  else
    raise "Unsupported protocol: #{protocol}"
  end
  true
end

#reopen ⇒ Object

After forking an active process call #reopen to re-open open the handles to resources



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# File 'lib/semantic_logger/appender/syslog.rb', line 167

def reopen
  case @protocol
  when :syslog
    method = ::Syslog.opened? ? :reopen : :open
    ::Syslog.send(method, application, options, facility)
  when :tcp
    # Use the local logger for @remote_syslog so errors with the remote logger can be recorded locally.
    @tcp_client_options[:logger] = logger
    @tcp_client_options[:server] = "#{@server}:#{@port}"
    @remote_syslog               = Net::TCPClient.new(@tcp_client_options)
  when :udp
    @remote_syslog = UDPSocket.new
  else
    raise "Unsupported protocol: #{@protocol}"
  end
end