Class: LogStash::Inputs::Syslog

Inherits:
Base
  • Object
show all
Defined in:
lib/logstash/inputs/syslog.rb

Defined Under Namespace

Classes: TCPInput, UDPInput

Instance Attribute Summary

Attributes inherited from Base

#logger

Instance Method Summary collapse

Methods inherited from Base

#initialize, #tag

Constructor Details

This class inherits a constructor from LogStash::Inputs::Base

Instance Method Details

#receive(host, port, message) ⇒ Object 



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# File 'lib/logstash/inputs/syslog.rb', line 31

def receive(host, port, message)
  url = @url.clone
  url.host = host
  url.port = port

  # Do some syslog relay-like behavior.
  # * Add syslog headers if there are none
  event = LogStash::Event.new({
    "@message" => message,
    "@type" => @type,
    "@tags" => @tags.clone,
  })
  syslog_relay(event, url)
  @logger.debug(["Got event", event.class, event.to_hash])
  @callback.call(event)
end

#register ⇒ Object 



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# File 'lib/logstash/inputs/syslog.rb', line 10

def register
  if !@url.host or !@url.port
    @logger.fatal("No host or port given in #{self.class}: #{@url}")
    # TODO(sissel): Make this an actual exception class
    raise "configuration error"
  end

  @logger.info("Starting tcp listener for #{@url}")
  EventMachine::start_server(@url.host, @url.port, TCPInput, self, @logger)

  @logger.info("Starting udp listener for #{@url}")
  EventMachine::open_datagram_socket(@url.host, @url.port, UDPInput, self,
                                     @logger)

  # This comes from RFC3164, mostly.
  @@syslog_re ||= \
    /<([0-9]{1,3})>([A-z]{3} [0-9]{2} [0-9]{2}:[0-9]{2}:[0-9]{2}) (\S+) (.*)/
    #<priority       timestamp          Mmm dd hh:mm:ss             host  msg
end

#syslog_relay(event, url) ⇒ Object 



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# File 'lib/logstash/inputs/syslog.rb', line 54

def syslog_relay(event, url)
  match = @@syslog_re.match(event.message)
  if match
    # match[1,2,3,4] = {pri, timestamp, hostname, message}
    # Per RFC3164, priority = (facility * 8) + severity
    #                       = (facility << 3) & (severity)
    priority = match[1].to_i
    severity = priority & 7   # 7 is 111 (3 bits)
    facility = priority >> 3
    event.fields["priority"] = priority
    event.fields["severity"] = severity
    event.fields["facility"] = facility
   
    # TODO(sissel): Use the date filter, somehow.
    event.timestamp = LogStash::Time.to_iso8601(
      DateTime.strptime(match[2], "%b %d %H:%M:%S"))

    # At least the hostname is simple...
    url.host = match[3]
    url.port = nil
    event.source = url

    event.message = match[4]
  else
    @logger.info(["NOT SYSLOG", event.message])
    url.host = Socket.gethostname if url.host == "127.0.0.1"

    # RFC3164 says unknown messages get pri=13
    priority = 13
    severity = priority & 7   # 7 is 111 (3 bits)
    facility = priority >> 3
    event.fields["priority"] = 13
    event.fields["severity"] = 5   # 13 & 7 == 5
    event.fields["facility"] = 1   # 13 >> 3 == 1

    # Don't need to modify the message, here.
    # event.message = ...

    event.source = url
  end
end