Class: Fluent::Plugin::ForwardOutput::Node

Inherits:
Object
  • Object
show all
Extended by:
Forwardable
Defined in:
lib/fluent/plugin/out_forward.rb

Direct Known Subclasses

NoneHeartbeatNode

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(sender, server, failure:, connection_manager:, ack_handler:) ⇒ Node

Returns a new instance of Node.

Parameters:



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# File 'lib/fluent/plugin/out_forward.rb', line 565

def initialize(sender, server, failure:, connection_manager:, ack_handler:)
  @sender = sender
  @log = sender.log
  @compress = sender.compress
  @server = server

  @name = server.name
  @host = server.host
  @port = server.port
  @weight = server.weight
  @standby = server.standby
  @failure = failure
  @available = true

  # @hostname is used for certificate verification & TLS SNI
  host_is_hostname = !(IPAddr.new(@host) rescue false)
  @hostname = case
              when host_is_hostname then @host
              when @name then @name
              else nil
              end

  @usock = nil

  @handshake = HandshakeProtocol.new(
    log: @log,
    hostname: sender.security&.self_hostname,
    shared_key: server.shared_key || sender.security&.shared_key || '',
    password: server.password || '',
    username: server.username || '',
  )

  @resolved_host = nil
  @resolved_time = 0
  @resolved_once = false

  @connection_manager = connection_manager
  @ack_handler = ack_handler
end

Instance Attribute Details

#failure ⇒ Object (readonly)

for test



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# File 'lib/fluent/plugin/out_forward.rb', line 609

def failure
  @failure
end

#sockaddr ⇒ Object (readonly)

used by on_udp_heartbeat_response_recv



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# File 'lib/fluent/plugin/out_forward.rb', line 608

def sockaddr
  @sockaddr
end

#state ⇒ Object (readonly)

Returns the value of attribute state.



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# File 'lib/fluent/plugin/out_forward.rb', line 607

def state
  @state
end

#usock ⇒ Object

Returns the value of attribute usock.



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# File 'lib/fluent/plugin/out_forward.rb', line 605

def usock
  @usock
end

Instance Method Details

#available? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/fluent/plugin/out_forward.rb', line 615

def available?
  @available
end

#disable! ⇒ Object 



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# File 'lib/fluent/plugin/out_forward.rb', line 619

def disable!
  @available = false
end

#establish_connection(sock, ri) ⇒ Object 



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# File 'lib/fluent/plugin/out_forward.rb', line 633

def establish_connection(sock, ri)
  start_time = Fluent::Clock.now
  timeout = @sender.hard_timeout

  while ri.state != :established
    # Check for timeout to prevent infinite loop
    if Fluent::Clock.now - start_time > timeout
      @log.warn "handshake timeout after #{timeout}s", host: @host, port: @port
      disable!
      break
    end

    begin
      # TODO: On Ruby 2.2 or earlier, read_nonblock doesn't work expectedly.
      # We need rewrite around here using new socket/server plugin helper.
      buf = sock.read_nonblock(@sender.read_length)
      if buf.empty?
        sleep @sender.read_interval
        next
      end
      Fluent::MessagePackFactory.msgpack_unpacker.feed_each(buf) do |data|
        if @handshake.invoke(sock, ri, data) == :established
          @log.debug "connection established", host: @host, port: @port
        end
      end
    rescue IO::WaitReadable
      # If the exception is Errno::EWOULDBLOCK or Errno::EAGAIN, it is extended by IO::WaitReadable.
      # So IO::WaitReadable can be used to rescue the exceptions for retrying read_nonblock.
      # https//docs.ruby-lang.org/en/2.3.0/IO.html#method-i-read_nonblock
      sleep @sender.read_interval unless ri.state == :established
    rescue SystemCallError => e
      @log.warn "disconnected by error", host: @host, port: @port, error: e
      disable!
      break
    rescue EOFError
      @log.warn "disconnected", host: @host, port: @port
      disable!
      break
    rescue HeloError => e
      @log.warn "received invalid helo message from #{@name}"
      disable!
      break
    rescue PingpongError => e
      @log.warn "connection refused to #{@name || @host}: #{e.message}"
      disable!
      break
    end
  end
end

#heartbeat(detect = true) ⇒ Object 



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# File 'lib/fluent/plugin/out_forward.rb', line 813

def heartbeat(detect=true)
  now = Time.now.to_f
  @failure.add(now)
  if detect && !available? && @failure.sample_size > @sender.recover_sample_size
    @available = true
    @log.warn "recovered forwarding server '#{@name}'", host: @host, port: @port
    true
  else
    nil
  end
end

#resolved_host ⇒ Object 



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# File 'lib/fluent/plugin/out_forward.rb', line 754

def resolved_host
  case @sender.expire_dns_cache
  when 0
    # cache is disabled
    resolve_dns!

  when nil
    # persistent cache
    @resolved_host ||= resolve_dns!

  else
    now = Fluent::EventTime.now
    rh = @resolved_host
    if !rh || now - @resolved_time >= @sender.expire_dns_cache
      rh = @resolved_host = resolve_dns!
      @resolved_time = now
    end
    rh
  end
end

#send_data(tag, chunk) ⇒ Object 



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# File 'lib/fluent/plugin/out_forward.rb', line 705

def send_data(tag, chunk)
  ack = @ack_handler && @ack_handler.create_ack(chunk.unique_id, self)
  connect(nil, ack: ack) do |sock, ri|
    ensure_established_connection(sock, ri)
    send_data_actual(sock, tag, chunk)
  end

  heartbeat(false)
  nil
end

#send_data_actual(sock, tag, chunk) ⇒ Object 



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# File 'lib/fluent/plugin/out_forward.rb', line 683

def send_data_actual(sock, tag, chunk)
  option = { 'size' => chunk.size, 'compressed' => @compress }
  option['chunk'] = Base64.encode64(chunk.unique_id) if @ack_handler

  # https://github.com/fluent/fluentd/wiki/Forward-Protocol-Specification-v1#packedforward-mode
  # out_forward always uses str32 type for entries.
  # str16 can store only 64kbytes, and it should be much smaller than buffer chunk size.

  tag = tag.dup.force_encoding(Encoding::UTF_8)

  sock.write @sender.forward_header                    # array, size=3
  sock.write tag.to_msgpack                            # 1. tag: String (str)
  chunk.open(compressed: @compress) do |chunk_io|
    entries = [0xdb, chunk_io.size].pack('CN')
    sock.write entries.force_encoding(Encoding::UTF_8) # 2. entries: String (str32)
    IO.copy_stream(chunk_io, sock)                     #    writeRawBody(packed_es)
  end
  sock.write option.to_msgpack                         # 3. option: Hash(map)

  # TODO: use bin32 for non-utf8 content(entries) when old msgpack-ruby (0.5.x or earlier) not supported
end

#send_heartbeat ⇒ Boolean

FORWARD_TCP_HEARTBEAT_DATA = FORWARD_HEADER + ''.to_msgpack + [].to_msgpack

Returns:

  • (Boolean) —

    return true if it needs to rebuild nodes



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# File 'lib/fluent/plugin/out_forward.rb', line 719

def send_heartbeat
  begin
    dest_addr = resolved_host
    @resolved_once = true
  rescue ::SocketError => e
    if !@resolved_once && @sender.ignore_network_errors_at_startup
      @log.warn "failed to resolve node name in heartbeating", server: @name || @host, error: e
      return false
    end
    raise
  end

  case @sender.heartbeat_type
  when :transport
    connect(dest_addr) do |sock, ri|
      ensure_established_connection(sock, ri)

      ## don't send any data to not cause a compatibility problem
      # sock.write FORWARD_TCP_HEARTBEAT_DATA

      # successful tcp connection establishment is considered as valid heartbeat.
      # When heartbeat is succeeded after detached, return true. It rebuilds weight array.
      heartbeat(true)
    end
  when :udp
    @usock.send "\0", 0, Socket.pack_sockaddr_in(@port, dest_addr)
    # response is going to receive at on_udp_heartbeat_response_recv
    false
  when :none # :none doesn't use this class
    raise "BUG: heartbeat_type none must not use Node"
  else
    raise "BUG: unknown heartbeat_type '#{@sender.heartbeat_type}'"
  end
end

#standby? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/fluent/plugin/out_forward.rb', line 623

def standby?
  @standby
end

#tick ⇒ Object 



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# File 'lib/fluent/plugin/out_forward.rb', line 783

def tick
  now = Time.now.to_f
  unless available?
    if @failure.hard_timeout?(now)
      @failure.clear
    end
    return nil
  end

  if @failure.hard_timeout?(now)
    @log.warn "detached forwarding server '#{@name}'", host: @host, port: @port, hard_timeout: true
    disable!
    @resolved_host = nil  # expire cached host
    @failure.clear
    return true
  end

  if @sender.phi_failure_detector
    phi = @failure.phi(now)
    if phi > @sender.phi_threshold
      @log.warn "detached forwarding server '#{@name}'", host: @host, port: @port, phi: phi, phi_threshold: @sender.phi_threshold
      disable!
      @resolved_host = nil  # expire cached host
      @failure.clear
      return true
    end
  end
  false
end

#validate_host_resolution! ⇒ Object 



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# File 'lib/fluent/plugin/out_forward.rb', line 611

def validate_host_resolution!
  resolved_host
end

#verify_connection ⇒ Object 



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# File 'lib/fluent/plugin/out_forward.rb', line 627

def verify_connection
  connect do |sock, ri|
    ensure_established_connection(sock, ri)
  end
end