Class: SemanticLogger::Appender::Syslog

Inherits:
Base
  • Object
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 Base

#formatter

Attributes inherited from Base

#filter, #name

Instance Method Summary collapse

Methods inherited from Base

colorized_formatter, #level

Methods inherited from Base

#benchmark, default_level, default_level=, #level, #level=, #payload, #pop_tags, #push_tags, #silence, #tagged, #tags, #with_payload

Constructor Details

#initialize(params = {}, &block) ⇒ Syslog

For more information on the Syslog constants used below see ruby-doc.org/stdlib-2.0.0/libdoc/syslog/rdoc/Syslog.html Parameters

:ident [String]
  Identity of the program
  Default: 'ruby'

: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 [Symbol]
  Default: SemanticLogger's log level.
  The minimum level at which this appender will write logs. Any log messages below this level will be ignored.

: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
    }

:local_hostname [String]
  Default: Socket.gethostname || `hostname`.strip
  Hostname to provide to the remote syslog.

:server [String]
  Default: 'syslog://localhost'
  For writing logs to a remote syslog server
  URI 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

: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



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# File 'lib/semantic_logger/appender/syslog.rb', line 145

def initialize(params = {}, &block)
  params     = params.dup
  @ident     = params.delete(:ident) || 'ruby'
  @options   = params.delete(:options) || (::Syslog::LOG_PID | ::Syslog::LOG_CONS)
  @facility  = params.delete(:facility) || ::Syslog::LOG_USER
  filter     = params.delete(:filter)
  level      = params.delete(:level)
  level_map  = params.delete(:level_map)
  @level_map = DEFAULT_LEVEL_MAP.dup
  @level_map.update(level_map) if level_map
  @server   = params.delete(:server) || 'syslog://localhost'
  uri       = URI(@server)
  @host     = uri.host || 'localhost'
  @protocol = (uri.scheme || :syslog).to_sym
  raise "Unknown protocol #{@protocol}!" unless [:syslog, :tcp, :udp].include?(@protocol)
  @host               = 'localhost' if @protocol == :syslog
  @port               = URI(@server).port || 514
  @local_hostname     = params.delete(:local_hostname) || Socket.gethostname || `hostname`.strip
  @tcp_client_options = params.delete(:tcp_client)

  # Warn about any unknown configuration options.
  params.each_pair { |key, val| SemanticLogger::Logger.logger.warn "Ignoring unknown configuration option: #{key.inspect} => #{val.inspect}" }

  # 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] = "#{@host}:#{@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

  reopen

  super(level, filter, &block)
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 38

def facility
  @facility
end

#host ⇒ Object (readonly)

Returns the value of attribute host.



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# File 'lib/semantic_logger/appender/syslog.rb', line 38

def host
  @host
end

#local_hostname ⇒ Object (readonly)

Returns the value of attribute local_hostname.



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# File 'lib/semantic_logger/appender/syslog.rb', line 38

def local_hostname
  @local_hostname
end

#port ⇒ Object (readonly)

Returns the value of attribute port.



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# File 'lib/semantic_logger/appender/syslog.rb', line 38

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 38

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 38

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 38

def server
  @server
end

Instance Method Details

#default_formatter ⇒ Object

Custom log formatter for syslog



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# File 'lib/semantic_logger/appender/syslog.rb', line 236

def default_formatter
  Proc.new do |log|
    tags = log.tags.collect { |tag| "[#{tag}]" }.join(" ") + " " if log.tags && (log.tags.size > 0)

    message = log.message.to_s
    message << ' -- ' << log.payload.inspect if log.payload
    log.each_exception do |exception, i|
      if i == 0
        message << ' -- '
      else
        message << "\nCause: "
      end
      message << "#{exception.class}: #{exception.message}\n#{(exception.backtrace || []).join("\n")}"
    end

    duration_str = log.duration ? "(#{'%.1f' % log.duration}ms) " : ''

    "#{log.level.to_s[0..0].upcase} [#{$$}:#{log.thread_name}] #{tags}#{duration_str}#{log.name} -- #{message}"
  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 231

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 host.



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# File 'lib/semantic_logger/appender/syslog.rb', line 211

def log(log)
  # Ensure minimum log level is met, and check filter
  return false if (level_index > (log.level_index || 0)) || !include_message?(log)

  case @protocol
  when :syslog
    # Since the Ruby Syslog API supports sprintf format strings, double up all existing '%'
    message = formatter.call(log).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, @host, @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 195

def reopen
  case @protocol
  when :syslog
    ::Syslog.open(@ident, @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

#syslog_packet_formatter(log) ⇒ Object

Format the syslog packet so it can be sent over TCP or UDP



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# File 'lib/semantic_logger/appender/syslog.rb', line 258

def syslog_packet_formatter(log)
  packet          = SyslogProtocol::Packet.new
  packet.hostname = @local_hostname
  packet.facility = @facility
  packet.severity = @level_map[log.level]
  packet.tag      = @ident
  packet.content  = default_formatter.call(log)
  packet.to_s
end