class Fluent::Syslog

Constants

DISCARD_STRING

declare const string for nullifying token if we decide to discard records

Attributes

sockets[RW]

Public Instance Methods

configure(conf) click to toggle source
Calls superclass method
# File lib/fluent/plugin/out_syslog.rb, line 31
def configure(conf)
  super
  # parses fluent config
end
create_packet(tag, time, record) click to toggle source
# File lib/fluent/plugin/out_syslog.rb, line 75
def create_packet(tag, time, record)
  # construct Syslog RFC 5424 compliant packet from fluent record, see:
  #   https://tools.ietf.org/html/rfc5424
  # example:
  #   '<134>1 2018-05-10T21:11:58-05:00 mysite.com myapp procid msgid \
  #     [xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx@41058 tag="syslog"] \
  #     message'

  if record.dig('log')
    begin
      record['message'] = record['log']
      record.delete('log')
    end
  end

  if record.dig('levelname')
    begin
      record['level'] = record['levelname']
      record.delete('levelname')
    end
  end

  if @parse_json
    begin
      parser = Yajl::Parser.new
      parsed_message = parser.parse(record['message'])
      if parsed_message.is_a?(Hash)
          record = record.merge(parsed_message)
      end
    rescue Yajl::ParseError
    end
  end

  pri             = 134                                          # 134 is hardcoded facility local0 and severity info
  version         = 1                                            # Syslog Protocol v1
  record_time     = time ? Time.at(time) : Time.now
  timestamp       = record_time.to_datetime.rfc3339
  hostname        = @syslog_hostname || '-'
  app_name        = @syslog_app || tag || '-'
  procid          = '-'                                          # set procid and msgid to NILVALUE
  msgid           = '-'
  pen             = @syslog_pen                                        
  tag             = @syslog_tag ? " tag=\"#{@syslog_tag},fluentd\"" : '' # write tag only if passed in through config
  token           = @syslog_token ? " key=\"#{@syslog_token}\"" : ''
  structured_data = "[#{pen} #{token} #{tag}]"
  msg             = Yajl.dump(record)

  "<#{pri}>#{version} #{timestamp} #{hostname} #{app_name} #{procid} #{msgid} #{structured_data} #{msg}\n"
end
create_socket(host, port) click to toggle source
# File lib/fluent/plugin/out_syslog.rb, line 58
def create_socket(host, port)
  log.info "initializing tcp socket for #{host}:#{port}"
  begin
    socket = TCPSocket.new(host, port)
    log.debug "enabling ssl for socket #{host}:#{port}"
    ssl = OpenSSL::SSL::SSLSocket.new(socket)
    # close tcp and ssl socket when either fails
    ssl.sync_close = true
    # initiate SSL/TLS handshake with server
    ssl.connect
  rescue => e
    log.warn "failed to create tcp socket #{host}:#{port}: #{e}"
    ssl = nil
  end
  ssl
end
format(tag, time, record) click to toggle source
# File lib/fluent/plugin/out_syslog.rb, line 47
def format(tag, time, record)
  [tag, time, record].to_msgpack
end
send_to_syslog(packet) click to toggle source
# File lib/fluent/plugin/out_syslog.rb, line 125
def send_to_syslog(packet)
  # recreate the socket if it's nil
  @socket ||= create_socket(@syslog_host, @syslog_port)
  if @socket.nil?
    err_msg = "Unable to create socket with #{@syslog_host}:#{@syslog_port}"
    raise SocketFailureError, err_msg
  else
    begin
      # send it
      @socket.write packet
    rescue => e
      # socket failed, reset to nil to recreate for the next write
      @socket = nil
      err_msg = "Closing socket. #{e.class} writing to '#{@syslog_host}:#{@syslog_port}': #{e}"
      raise SocketFailureError, err_msg, e.backtrace
    end
  end
end
shutdown() click to toggle source
Calls superclass method
# File lib/fluent/plugin/out_syslog.rb, line 42
def shutdown
  super
  @socket.close
end
start() click to toggle source
Calls superclass method
# File lib/fluent/plugin/out_syslog.rb, line 36
def start
  super
  # create initial socket based on config param
  @socket = create_socket(@syslog_host, @syslog_port)
end
write(chunk) click to toggle source
# File lib/fluent/plugin/out_syslog.rb, line 51
def write(chunk)
  chunk.msgpack_each { |(tag, time, record)|
    packet = create_packet(tag, time, record)
    send_to_syslog(packet)
  }
end