Class: Fluent::Syslog

Inherits:
BufferedOutput
  • Object
show all
Defined in:
lib/fluent/plugin/out_syslog.rb

Defined Under Namespace

Classes: SocketFailureError

Constant Summary collapse

DISCARD_STRING =

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

'DISCARD'

Instance Attribute Summary collapse

Instance Method Summary collapse

Instance Attribute Details

#sockets ⇒ Object

Returns the value of attribute sockets.



6
7
8
 
# File 'lib/fluent/plugin/out_syslog.rb', line 6

def sockets
  @sockets
end

Instance Method Details

#configure(conf) ⇒ Object 



31
32
33
34
 
# File 'lib/fluent/plugin/out_syslog.rb', line 31

def configure(conf)
  super
  # parses fluent config
end

#create_packet(tag, time, record) ⇒ Object 



75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
 
# 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) ⇒ Object 



58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
 
# 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) ⇒ Object 



47
48
49
 
# File 'lib/fluent/plugin/out_syslog.rb', line 47

def format(tag, time, record)
  [tag, time, record].to_msgpack
end

#send_to_syslog(packet) ⇒ Object 



125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
 
# 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 ⇒ Object 



42
43
44
45
 
# File 'lib/fluent/plugin/out_syslog.rb', line 42

def shutdown
  super
  @socket.close
end

#start ⇒ Object 



36
37
38
39
40
 
# 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) ⇒ Object 



51
52
53
54
55
56
 
# 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