Class: SemanticLogger::Appender::Syslog

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

Constant Summary collapse

DEFAULT_LEVEL_MAP =

Default mapping of ruby log levels to syslog log levels

::Syslog::LOG_EMERG - “System is unusable” ::Syslog::LOG_ALERT - “Action needs to be taken immediately” ::Syslog::LOG_CRIT - “A critical condition has occurred” ::Syslog::LOG_ERR - “An error occurred” ::Syslog::LOG_WARNING - “Warning of a possible problem” ::Syslog::LOG_NOTICE - “A normal but significant condition occurred” ::Syslog::LOG_INFO - “Informational message” ::Syslog::LOG_DEBUG - “Debugging information”

{
  fatal: ::Syslog::LOG_CRIT,
  error: ::Syslog::LOG_ERR,
  warn:  ::Syslog::LOG_WARNING,
  info:  ::Syslog::LOG_NOTICE,
  debug: ::Syslog::LOG_INFO,
  trace: ::Syslog::LOG_DEBUG
}

Instance Attribute Summary collapse

Attributes inherited from Subscriber

#application, #formatter, #host

Attributes inherited from Base

#filter, #name

Instance Method Summary collapse

Methods inherited from Subscriber

#close, #default_formatter, #level

Methods inherited from Base

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

Constructor Details

#initialize(options = {}, &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://www.omniref.com/ruby/gems/net_tcp_client/1.0.0/symbols/Net::TCPClient/initialize

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

formatter: [Object|Proc]
  An instance of a class that implements #call, or a Proc to be used to format
  the output from this appender
  Default: Use the built-in formatter (See: #call)

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

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]
  Supply a custom map of SemanticLogger levels to syslog levels.
  For example, passing in { warn: ::Syslog::LOG_NOTICE }
    would result in a log mapping that matches the default level map,
    except for :warn, which ends up with a LOG_NOTICE level instead of a
    LOG_WARNING one.
  Without overriding any parameters, the level map will be
    LEVEL_MAP = {
      fatal:   ::Syslog::LOG_CRIT,
      error:   ::Syslog::LOG_ERR,
      warn:    ::Syslog::LOG_WARNING,
      info:    ::Syslog::LOG_NOTICE,
      debug:   ::Syslog::LOG_INFO,
      trace:   ::Syslog::LOG_DEBUG
    }

format: [Symbol]
  Format for the Syslog message
    :syslog uses the default syslog format
    :json uses the CEE JSON Syslog format
       Example: "@cee: #{JSON.dump(data)}"
  Default: :syslog



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# File 'lib/semantic_logger/appender/syslog.rb', line 149

def initialize(options = {}, &block)
  options             = options.dup
  @options            = options.delete(:options) || (::Syslog::LOG_PID | ::Syslog::LOG_CONS)
  @facility           = options.delete(:facility) || ::Syslog::LOG_USER
  level_map           = options.delete(:level_map)
  @url                = options.delete(:url) || options.delete(:server) || 'syslog://localhost'
  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 = options.delete(:tcp_client)

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

  @level_map = DEFAULT_LEVEL_MAP.dup
  @level_map.update(level_map) if level_map

  # The syslog_protocol gem is required when logging over TCP or UDP.
  if [: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
      @tcp_client_options          ||= {}
      @tcp_client_options[:server] = "#{@server}:#{@port}"
      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(options, &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 43

def facility
  @facility
end

#port ⇒ Object (readonly)

Returns the value of attribute port.



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# File 'lib/semantic_logger/appender/syslog.rb', line 43

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 43

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 43

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 43

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 43

def url
  @url
end

Instance Method Details

#call(log, logger) ⇒ Object

Custom log formatter for syslog. Only difference is the removal of the timestamp string since it is in the syslog packet.



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# File 'lib/semantic_logger/appender/syslog.rb', line 234

def call(log, logger)
  # Header with date, time, log level and process info
  message = "#{log.level_to_s} [#{log.process_info}]"

  # Tags
  message << ' ' << log.tags.collect { |tag| "[#{tag}]" }.join(' ') if log.tags && (log.tags.size > 0)

  # Duration
  message << " (#{log.duration_human})" if log.duration

  # Class / app name
  message << " #{log.name}"

  # Log message
  message << " -- #{log.message}" if log.message

  # Payload
  if payload = log.payload_to_s
    message << ' -- ' << payload
  end

  # Exceptions
  if log.exception
    message << " -- Exception: #{log.exception.class}: #{log.exception.message}\n"
    message << log.backtrace_to_s
  end
  message
end

#flush ⇒ Object

Flush is called by the semantic_logger during shutdown.



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# File 'lib/semantic_logger/appender/syslog.rb', line 228

def flush
  @remote_syslog.flush if @remote_syslog && @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 209

def log(log)
  return false unless should_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("#{syslog_packet_formatter(log)}\r\n") }
  when :udp
    @remote_syslog.send syslog_packet_formatter(log), 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 193

def reopen
  case @protocol
  when :syslog
    ::Syslog.open(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] = SemanticLogger::Logger.logger
    @remote_syslog               = Net::TCPClient.new(@tcp_client_options)
  when :udp
    @remote_syslog = UDPSocket.new
  else
    raise "Unsupported protocol: #{@protocol}"
  end
end