class Fluent::Plugin::Output

Constants

CHUNKING_FIELD_WARN_NUM
CHUNK_KEY_PATTERN
CHUNK_KEY_PLACEHOLDER_PATTERN
CHUNK_TAG_PLACEHOLDER_PATTERN
DequeuedChunkInfo
FORMAT_COMPRESSED_MSGPACK_STREAM
FORMAT_COMPRESSED_MSGPACK_STREAM_TIME_INT
FORMAT_MSGPACK_STREAM
FORMAT_MSGPACK_STREAM_TIME_INT
FlushThreadState

Internal states

TIMESTAMP_CHECK_BASE_TIME
TIME_KEY_PLACEHOLDER_THRESHOLDS

Attributes

as_secondary[R]
buffer[R]

for tests

chunk_key_tag[R]

for tests

chunk_key_time[R]

for tests

chunk_keys[R]

for tests

delayed_commit[R]
delayed_commit_timeout[R]
dequeued_chunks[RW]
dequeued_chunks_mutex[RW]
emit_count[R]
emit_records[R]
num_errors[R]
output_enqueue_thread_waiting[RW]
retry[R]

for tests

retry_for_error_chunk[RW]

output_enqueue_thread_waiting: for test of output.rb itself

rollback_count[R]
secondary[R]

for tests

timekey_zone[R]
write_count[R]

Public Class Methods

new() click to toggle source
Calls superclass method Fluent::PluginLoggerMixin::new
# File lib/fluent/plugin/output.rb, line 164
def initialize
  super
  @counters_monitor = Monitor.new
  @buffering = false
  @delayed_commit = false
  @as_secondary = false
  @primary_instance = nil

  # TODO: well organized counters
  @num_errors = 0
  @emit_count = 0
  @emit_records = 0
  @write_count = 0
  @rollback_count = 0

  # How to process events is decided here at once, but it will be decided in delayed way on #configure & #start
  if implement?(:synchronous)
    if implement?(:buffered) || implement?(:delayed_commit)
      @buffering = nil # do #configure or #start to determine this for full-featured plugins
    else
      @buffering = false
    end
  else
    @buffering = true
  end
  @custom_format = implement?(:custom_format)
  @enable_msgpack_streamer = false # decided later

  @buffer = nil
  @secondary = nil
  @retry = nil
  @dequeued_chunks = nil
  @dequeued_chunks_mutex = nil
  @output_enqueue_thread = nil
  @output_flush_threads = nil

  @simple_chunking = nil
  @chunk_keys = @chunk_key_time = @chunk_key_tag = nil
  @flush_mode = nil
  @timekey_zone = nil

  @retry_for_error_chunk = false
end

Public Instance Methods

acts_as_secondary(primary) click to toggle source
# File lib/fluent/plugin/output.rb, line 208
def acts_as_secondary(primary)
  @as_secondary = true
  @primary_instance = primary
  @chunk_keys = @primary_instance.chunk_keys || []
  @chunk_key_tag = @primary_instance.chunk_key_tag || false
  if @primary_instance.chunk_key_time
    @chunk_key_time = @primary_instance.chunk_key_time
    @timekey_zone = @primary_instance.timekey_zone
    @output_time_formatter_cache = {}
  end
  self.context_router = primary.context_router

  (class << self; self; end).module_eval do
    define_method(:commit_write){ |chunk_id| @primary_instance.commit_write(chunk_id, delayed: delayed_commit, secondary: true) }
    define_method(:rollback_write){ |chunk_id| @primary_instance.rollback_write(chunk_id) }
  end
end
after_shutdown() click to toggle source
Calls superclass method Fluent::Plugin::Base#after_shutdown
# File lib/fluent/plugin/output.rb, line 469
def after_shutdown
  try_rollback_all if @buffering && !@as_secondary # rollback regardless with @delayed_commit, because secondary may do it
  @secondary.after_shutdown if @secondary

  if @buffering && @buffer
    @buffer.after_shutdown

    @output_flush_threads_running = false
    if @output_flush_threads && !@output_flush_threads.empty?
      @output_flush_threads.each do |state|
        state.thread.run if state.thread.alive? # to wakeup thread and make it to stop by itself
      end
      @output_flush_threads.each do |state|
        state.thread.join
      end
    end
  end

  super
end
after_start() click to toggle source
Calls superclass method Fluent::Plugin::Base#after_start
# File lib/fluent/plugin/output.rb, line 431
def after_start
  super
  @secondary.after_start if @secondary
end
before_shutdown() click to toggle source
Calls superclass method Fluent::Plugin::Base#before_shutdown
# File lib/fluent/plugin/output.rb, line 443
def before_shutdown
  @secondary.before_shutdown if @secondary

  if @buffering && @buffer
    if @flush_at_shutdown
      force_flush
    end
    @buffer.before_shutdown
    # Need to ensure to stop enqueueing ... after #shutdown, we cannot write any data
    @output_enqueue_thread_running = false
    if @output_enqueue_thread && @output_enqueue_thread.alive?
      @output_enqueue_thread.wakeup
      @output_enqueue_thread.join
    end
  end

  super
end
check_slow_flush(start) click to toggle source
# File lib/fluent/plugin/output.rb, line 1060
def check_slow_flush(start)
  elapsed_time = Fluent::Clock.now - start
  if elapsed_time > @slow_flush_log_threshold
    log.warn "buffer flush took longer time than slow_flush_log_threshold:",
             elapsed_time: elapsed_time, slow_flush_log_threshold: @slow_flush_log_threshold, plugin_id: self.plugin_id
  end
end
close() click to toggle source
Calls superclass method Fluent::Plugin::Base#close
# File lib/fluent/plugin/output.rb, line 490
def close
  @buffer.close if @buffering && @buffer
  @secondary.close if @secondary

  super
end
commit_write(chunk_id, delayed: @delayed_commit, secondary: false) click to toggle source
# File lib/fluent/plugin/output.rb, line 922
def commit_write(chunk_id, delayed: @delayed_commit, secondary: false)
  log.trace "committing write operation to a chunk", chunk: dump_unique_id_hex(chunk_id), delayed: delayed
  if delayed
    @dequeued_chunks_mutex.synchronize do
      @dequeued_chunks.delete_if{ |info| info.chunk_id == chunk_id }
    end
  end
  @buffer.purge_chunk(chunk_id)

  @retry_mutex.synchronize do
    if @retry # success to flush chunks in retries
      if secondary
        log.warn "retry succeeded by secondary.", chunk_id: dump_unique_id_hex(chunk_id)
      else
        log.warn "retry succeeded.", chunk_id: dump_unique_id_hex(chunk_id)
      end
      @retry = nil
    end
  end
end
configure(conf) click to toggle source
Calls superclass method Fluent::PluginLoggerMixin#configure
# File lib/fluent/plugin/output.rb, line 226
def configure(conf)
  unless implement?(:synchronous) || implement?(:buffered) || implement?(:delayed_commit)
    raise "BUG: output plugin must implement some methods. see developer documents."
  end

  has_buffer_section = (conf.elements(name: 'buffer').size > 0)
  has_flush_interval = conf.has_key?('flush_interval')

  super

  if has_buffer_section
    unless implement?(:buffered) || implement?(:delayed_commit)
      raise Fluent::ConfigError, "<buffer> section is configured, but plugin '#{self.class}' doesn't support buffering"
    end
    @buffering = true
  else # no buffer sections
    if implement?(:synchronous)
      if !implement?(:buffered) && !implement?(:delayed_commit)
        if @as_secondary
          raise Fluent::ConfigError, "secondary plugin '#{self.class}' must support buffering, but doesn't."
        end
        @buffering = false
      else
        if @as_secondary
          # secondary plugin always works as buffered plugin without buffer instance
          @buffering = true
        else
          # @buffering.nil? shows that enabling buffering or not will be decided in lazy way in #start
          @buffering = nil
        end
      end
    else # buffered or delayed_commit is supported by `unless` of first line in this method
      @buffering = true
    end
  end

  if @as_secondary
    if !@buffering && !@buffering.nil?
      raise Fluent::ConfigError, "secondary plugin '#{self.class}' must support buffering, but doesn't"
    end
  end

  if (@buffering || @buffering.nil?) && !@as_secondary
    # When @buffering.nil?, @buffer_config was initialized with default value for all parameters.
    # If so, this configuration MUST success.
    @chunk_keys = @buffer_config.chunk_keys.dup
    @chunk_key_time = !!@chunk_keys.delete('time')
    @chunk_key_tag = !!@chunk_keys.delete('tag')
    if @chunk_keys.any?{ |key| key !~ CHUNK_KEY_PATTERN }
      raise Fluent::ConfigError, "chunk_keys specification includes invalid char"
    end

    if @chunk_key_time
      raise Fluent::ConfigError, "<buffer ...> argument includes 'time', but timekey is not configured" unless @buffer_config.timekey
      Fluent::Timezone.validate!(@buffer_config.timekey_zone)
      @timekey_zone = @buffer_config.timekey_use_utc ? '+0000' : @buffer_config.timekey_zone
      @output_time_formatter_cache = {}
    end

    if (@chunk_key_tag ? 1 : 0) + @chunk_keys.size >= CHUNKING_FIELD_WARN_NUM
      log.warn "many chunk keys specified, and it may cause too many chunks on your system."
    end

    # no chunk keys or only tags (chunking can be done without iterating event stream)
    @simple_chunking = !@chunk_key_time && @chunk_keys.empty?

    @flush_mode = @buffer_config.flush_mode
    if @flush_mode == :default
      if has_flush_interval
        log.info "'flush_interval' is configured at out side of <buffer>. 'flush_mode' is set to 'interval' to keep existing behaviour"
        @flush_mode = :interval
      else
        @flush_mode = (@chunk_key_time ? :lazy : :interval)
      end
    end

    buffer_type = @buffer_config[:@type]
    buffer_conf = conf.elements(name: 'buffer').first || Fluent::Config::Element.new('buffer', '', {}, [])
    @buffer = Plugin.new_buffer(buffer_type, parent: self)
    @buffer.configure(buffer_conf)

    @flush_at_shutdown = @buffer_config.flush_at_shutdown
    if @flush_at_shutdown.nil?
      @flush_at_shutdown = if @buffer.persistent?
                             false
                           else
                             true # flush_at_shutdown is true in default for on-memory buffer
                           end
    elsif !@flush_at_shutdown && !@buffer.persistent?
      buf_type = Plugin.lookup_type_from_class(@buffer.class)
      log.warn "'flush_at_shutdown' is false, and buffer plugin '#{buf_type}' is not persistent buffer."
      log.warn "your configuration will lose buffered data at shutdown. please confirm your configuration again."
    end

    if (@flush_mode != :interval) && buffer_conf.has_key?('flush_interval')
      if buffer_conf.has_key?('flush_mode')
        raise Fluent::ConfigError, "'flush_interval' can't be specified when 'flush_mode' is not 'interval' explicitly: '#{@flush_mode}'"
      else
        log.warn "'flush_interval' is ignored because default 'flush_mode' is not 'interval': '#{@flush_mode}'"
      end
    end
  end

  if @secondary_config
    raise Fluent::ConfigError, "Invalid <secondary> section for non-buffered plugin" unless @buffering
    raise Fluent::ConfigError, "<secondary> section cannot have <buffer> section" if @secondary_config.buffer
    raise Fluent::ConfigError, "<secondary> section cannot have <secondary> section" if @secondary_config.secondary
    raise Fluent::ConfigError, "<secondary> section and 'retry_forever' are exclusive" if @buffer_config.retry_forever

    secondary_type = @secondary_config[:@type]
    unless secondary_type
      secondary_type = conf['@type'] # primary plugin type
    end
    secondary_conf = conf.elements(name: 'secondary').first
    @secondary = Plugin.new_output(secondary_type)
    @secondary.acts_as_secondary(self)
    @secondary.configure(secondary_conf)
    if (self.class != @secondary.class) && (@custom_format || @secondary.implement?(:custom_format))
      log.warn "secondary type should be same with primary one", primary: self.class.to_s, secondary: @secondary.class.to_s
    end
  else
    @secondary = nil
  end

  self
end
emit_buffered(tag, es) click to toggle source
# File lib/fluent/plugin/output.rb, line 724
def emit_buffered(tag, es)
  @counters_monitor.synchronize{ @emit_count += 1 }
  begin
    execute_chunking(tag, es, enqueue: (@flush_mode == :immediate))
    if !@retry && @buffer.queued?
      submit_flush_once
    end
  rescue
    # TODO: separate number of errors into emit errors and write/flush errors
    @counters_monitor.synchronize{ @num_errors += 1 }
    raise
  end
end
emit_events(tag, es) click to toggle source
# File lib/fluent/plugin/output.rb, line 704
def emit_events(tag, es)
  # actually this method will be overwritten by #configure
  if @buffering
    emit_buffered(tag, es)
  else
    emit_sync(tag, es)
  end
end
emit_sync(tag, es) click to toggle source
# File lib/fluent/plugin/output.rb, line 713
def emit_sync(tag, es)
  @counters_monitor.synchronize{ @emit_count += 1 }
  begin
    process(tag, es)
    @counters_monitor.synchronize{ @emit_records += es.size }
  rescue
    @counters_monitor.synchronize{ @num_errors += 1 }
    raise
  end
end
enqueue_thread_run() click to toggle source
# File lib/fluent/plugin/output.rb, line 1181
def enqueue_thread_run
  value_for_interval = nil
  if @flush_mode == :interval
    value_for_interval = @buffer_config.flush_interval
  end
  if @chunk_key_time
    if !value_for_interval || @buffer_config.timekey < value_for_interval
      value_for_interval = @buffer_config.timekey
    end
  end
  unless value_for_interval
    raise "BUG: both of flush_interval and timekey are disabled"
  end
  interval = value_for_interval / 11.0
  if interval < @buffer_config.flush_thread_interval
    interval = @buffer_config.flush_thread_interval
  end

  while !self.after_started? && !self.stopped?
    sleep 0.5
  end
  log.debug "enqueue_thread actually running"

  begin
    while @output_enqueue_thread_running
      now_int = Time.now.to_i
      if @output_flush_interrupted
        sleep interval
        next
      end

      @output_enqueue_thread_mutex.lock
      begin
        if @flush_mode == :interval
          flush_interval = @buffer_config.flush_interval.to_i
          # This block should be done by integer values.
          # If both of flush_interval & flush_thread_interval are 1s, expected actual flush timing is 1.5s.
          # If we use integered values for this comparison, expected actual flush timing is 1.0s.
          @buffer.enqueue_all{ |metadata, chunk| chunk.created_at.to_i + flush_interval <= now_int }
        end

        if @chunk_key_time
          timekey_unit = @buffer_config.timekey
          timekey_wait = @buffer_config.timekey_wait
          current_timekey = now_int - now_int % timekey_unit
          @buffer.enqueue_all{ |metadata, chunk| metadata.timekey < current_timekey && metadata.timekey + timekey_unit + timekey_wait <= now_int }
        end
      rescue => e
        raise if @under_plugin_development
        log.error "unexpected error while checking flushed chunks. ignored.", error: e
        log.error_backtrace
      ensure
        @output_enqueue_thread_waiting = false
        @output_enqueue_thread_mutex.unlock
      end
      sleep interval
    end
  rescue => e
    # normal errors are rescued by inner begin-rescue clause.
    log.error "error on enqueue thread", error: e
    log.error_backtrace
    raise
  end
end
enqueue_thread_wait() click to toggle source

only for tests of output plugin

# File lib/fluent/plugin/output.rb, line 1162
def enqueue_thread_wait
  @output_enqueue_thread_mutex.synchronize do
    @output_flush_interrupted = false
    @output_enqueue_thread_waiting = true
  end
  require 'timeout'
  Timeout.timeout(10) do
    Thread.pass while @output_enqueue_thread_waiting
  end
end
execute_chunking(tag, es, enqueue: false) click to toggle source
# File lib/fluent/plugin/output.rb, line 788
def execute_chunking(tag, es, enqueue: false)
  if @simple_chunking
    handle_stream_simple(tag, es, enqueue: enqueue)
  elsif @custom_format
    handle_stream_with_custom_format(tag, es, enqueue: enqueue)
  else
    handle_stream_with_standard_format(tag, es, enqueue: enqueue)
  end
end
extract_placeholders(str, metadata) click to toggle source

TODO: optimize this code

# File lib/fluent/plugin/output.rb, line 663
def extract_placeholders(str, metadata)
  if metadata.empty?
    str
  else
    rvalue = str.dup
    # strftime formatting
    if @chunk_key_time # this section MUST be earlier than rest to use raw 'str'
      @output_time_formatter_cache[str] ||= Fluent::Timezone.formatter(@timekey_zone, str)
      rvalue = @output_time_formatter_cache[str].call(metadata.timekey)
    end
    # ${tag}, ${tag[0]}, ${tag[1]}, ...
    if @chunk_key_tag
      if str.include?('${tag}')
        rvalue = rvalue.gsub('${tag}', metadata.tag)
      end
      if str =~ CHUNK_TAG_PLACEHOLDER_PATTERN
        hash = {}
        metadata.tag.split('.').each_with_index do |part, i|
          hash["${tag[#{i}]}"] = part
        end
        rvalue = rvalue.gsub(CHUNK_TAG_PLACEHOLDER_PATTERN, hash)
      end
      if rvalue =~ CHUNK_TAG_PLACEHOLDER_PATTERN
        log.warn "tag placeholder '#{$1}' not replaced. tag:#{metadata.tag}, template:#{str}"
      end
    end
    # ${a_chunk_key}, ...
    if !@chunk_keys.empty? && metadata.variables
      hash = {'${tag}' => '${tag}'} # not to erase this wrongly
      @chunk_keys.each do |key|
        hash["${#{key}}"] = metadata.variables[key.to_sym]
      end
      rvalue = rvalue.gsub(CHUNK_KEY_PLACEHOLDER_PATTERN, hash)
    end
    if rvalue =~ CHUNK_KEY_PLACEHOLDER_PATTERN
      log.warn "chunk key placeholder '#{$1}' not replaced. templace:#{str}"
    end
    rvalue
  end
end
flush_thread_run(state) click to toggle source
# File lib/fluent/plugin/output.rb, line 1246
def flush_thread_run(state)
  flush_thread_interval = @buffer_config.flush_thread_interval

  state.next_clock = Fluent::Clock.now + flush_thread_interval

  while !self.after_started? && !self.stopped?
    sleep 0.5
  end
  log.debug "flush_thread actually running"

  begin
    # This thread don't use `thread_current_running?` because this thread should run in `before_shutdown` phase
    while @output_flush_threads_running
      current_clock = Fluent::Clock.now
      interval = state.next_clock - current_clock

      if state.next_clock <= current_clock && (!@retry || @retry_mutex.synchronize{ @retry.next_time } <= Time.now)
        try_flush

        # next_flush_time uses flush_thread_interval or flush_thread_burst_interval (or retrying)
        interval = next_flush_time.to_f - Time.now.to_f
        # TODO: if secondary && delayed-commit, next_flush_time will be much longer than expected
        #       because @retry still exists (#commit_write is not called yet in #try_flush)
        #       @retry should be cleared if delayed commit is enabled? Or any other solution?
        state.next_clock = Fluent::Clock.now + interval
      end

      if @dequeued_chunks_mutex.synchronize{ !@dequeued_chunks.empty? && @dequeued_chunks.first.expired? }
        unless @output_flush_interrupted
          try_rollback_write
        end
      end

      sleep interval if interval > 0
    end
  rescue => e
    # normal errors are rescued by output plugins in #try_flush
    # so this rescue section is for critical & unrecoverable errors
    log.error "error on output thread", error: e
    log.error_backtrace
    raise
  end
end
flush_thread_wakeup() click to toggle source

only for tests of output plugin

# File lib/fluent/plugin/output.rb, line 1174
def flush_thread_wakeup
  @output_flush_threads.each do |state|
    state.next_clock = 0
    state.thread.run
  end
end
force_flush() click to toggle source
# File lib/fluent/plugin/output.rb, line 1142
def force_flush
  if @buffering
    @buffer.enqueue_all
    submit_flush_all
  end
end
format(tag, time, record) click to toggle source
# File lib/fluent/plugin/output.rb, line 120
def format(tag, time, record)
  # standard msgpack_event_stream chunk will be used if this method is not implemented in plugin subclass
  raise NotImplementedError, "BUG: output plugins MUST implement this method"
end
formatted_to_msgpack_binary() click to toggle source
# File lib/fluent/plugin/output.rb, line 125
def formatted_to_msgpack_binary
  # To indicate custom format method (#format) returns msgpack binary or not.
  # If #format returns msgpack binary, override this method to return true.
  false
end
generate_format_proc() click to toggle source
# File lib/fluent/plugin/output.rb, line 844
def generate_format_proc
  if @buffer && @buffer.compress == :gzip
    @time_as_integer ? FORMAT_COMPRESSED_MSGPACK_STREAM_TIME_INT : FORMAT_COMPRESSED_MSGPACK_STREAM
  else
    @time_as_integer ? FORMAT_MSGPACK_STREAM_TIME_INT : FORMAT_MSGPACK_STREAM
  end
end
get_placeholders_keys(str) click to toggle source
# File lib/fluent/plugin/output.rb, line 658
def get_placeholders_keys(str)
  str.scan(CHUNK_KEY_PLACEHOLDER_PATTERN).map{|ph| ph[2..-2]}.reject{|s| s == "tag"}.sort
end
get_placeholders_tag(str) click to toggle source

-1 means whole tag

# File lib/fluent/plugin/output.rb, line 645
def get_placeholders_tag(str)
  # [["tag"],["tag[0]"]]
  parts = []
  str.scan(CHUNK_TAG_PLACEHOLDER_PATTERN).map(&:first).each do |ph|
    if ph == "tag"
      parts << -1
    elsif ph =~ /^tag\[(\d+)\]$/
      parts << $1.to_i
    end
  end
  parts.sort
end
get_placeholders_time(str) click to toggle source

it's not validated to use timekey larger than 1 day

# File lib/fluent/plugin/output.rb, line 635
def get_placeholders_time(str)
  base_str = TIMESTAMP_CHECK_BASE_TIME.strftime(str)
  TIME_KEY_PLACEHOLDER_THRESHOLDS.each do |triple|
    sec = triple.first
    return triple if (TIMESTAMP_CHECK_BASE_TIME + sec).strftime(str) != base_str
  end
  nil
end
handle_stream_simple(tag, es, enqueue: false) click to toggle source
# File lib/fluent/plugin/output.rb, line 897
def handle_stream_simple(tag, es, enqueue: false)
  format_proc = nil
  meta = metadata((@chunk_key_tag ? tag : nil), nil, nil)
  records = es.size
  if @custom_format
    records = 0
    data = []
    es.each do |time, record|
      res = format(tag, time, record)
      if res
        data << res
        records += 1
      end
    end
  else
    format_proc = generate_format_proc
    data = es
  end
  write_guard do
    @buffer.write({meta => data}, format: format_proc, enqueue: enqueue)
  end
  @counters_monitor.synchronize{ @emit_records += records }
  true
end
handle_stream_with_custom_format(tag, es, enqueue: false) click to toggle source

metadata_and_data is a Hash of:

(standard format) metadata => event stream
(custom format)   metadata => array of formatted event

For standard format, formatting should be done for whole event stream, but

"whole event stream" may be a split of "es" here when it's bigger than chunk_limit_size.
`@buffer.write` will do this splitting.

For custom format, formatting will be done here. Custom formatting always requires

iteration of event stream, and it should be done just once even if total event stream size
is bigger than chunk_limit_size because of performance.
# File lib/fluent/plugin/output.rb, line 861
def handle_stream_with_custom_format(tag, es, enqueue: false)
  meta_and_data = {}
  records = 0
  es.each do |time, record|
    meta = metadata(tag, time, record)
    meta_and_data[meta] ||= []
    res = format(tag, time, record)
    if res
      meta_and_data[meta] << res
      records += 1
    end
  end
  write_guard do
    @buffer.write(meta_and_data, enqueue: enqueue)
  end
  @counters_monitor.synchronize{ @emit_records += records }
  true
end
handle_stream_with_standard_format(tag, es, enqueue: false) click to toggle source
# File lib/fluent/plugin/output.rb, line 880
def handle_stream_with_standard_format(tag, es, enqueue: false)
  format_proc = generate_format_proc
  meta_and_data = {}
  records = 0
  es.each do |time, record|
    meta = metadata(tag, time, record)
    meta_and_data[meta] ||= MultiEventStream.new
    meta_and_data[meta].add(time, record)
    records += 1
  end
  write_guard do
    @buffer.write(meta_and_data, format: format_proc, enqueue: enqueue)
  end
  @counters_monitor.synchronize{ @emit_records += records }
  true
end
implement?(feature) click to toggle source
# File lib/fluent/plugin/output.rb, line 516
def implement?(feature)
  methods_of_plugin = self.class.instance_methods(false)
  case feature
  when :synchronous    then methods_of_plugin.include?(:process) || support_in_v12_style?(:synchronous)
  when :buffered       then methods_of_plugin.include?(:write) || support_in_v12_style?(:buffered)
  when :delayed_commit then methods_of_plugin.include?(:try_write)
  when :custom_format  then methods_of_plugin.include?(:format) || support_in_v12_style?(:custom_format)
  else
    raise ArgumentError, "Unknown feature for output plugin: #{feature}"
  end
end
interrupt_flushes() click to toggle source

only for tests of output plugin

# File lib/fluent/plugin/output.rb, line 1157
def interrupt_flushes
  @output_flush_interrupted = true
end
metadata(tag, time, record) click to toggle source

TODO: optimize this code

# File lib/fluent/plugin/output.rb, line 739
def metadata(tag, time, record)
  # this arguments are ordered in output plugin's rule
  # Metadata 's argument order is different from this one (timekey, tag, variables)

  raise ArgumentError, "tag must be a String: #{tag.class}" unless tag.nil? || tag.is_a?(String)
  raise ArgumentError, "time must be a Fluent::EventTime (or Integer): #{time.class}" unless time.nil? || time.is_a?(Fluent::EventTime) || time.is_a?(Integer)
  raise ArgumentError, "record must be a Hash: #{record.class}" unless record.nil? || record.is_a?(Hash)

  if @chunk_keys.nil? && @chunk_key_time.nil? && @chunk_key_tag.nil?
    # for tests
    return Struct.new(:timekey, :tag, :variables).new
  end

  # timekey is int from epoch, and `timekey - timekey % 60` is assumed to mach with 0s of each minutes.
  # it's wrong if timezone is configured as one which supports leap second, but it's very rare and
  # we can ignore it (especially in production systems).
  if @chunk_keys.empty?
    if !@chunk_key_time && !@chunk_key_tag
      @buffer.metadata()
    elsif @chunk_key_time && @chunk_key_tag
      time_int = time.to_i
      timekey = (time_int - (time_int % @buffer_config.timekey)).to_i
      @buffer.metadata(timekey: timekey, tag: tag)
    elsif @chunk_key_time
      time_int = time.to_i
      timekey = (time_int - (time_int % @buffer_config.timekey)).to_i
      @buffer.metadata(timekey: timekey)
    else
      @buffer.metadata(tag: tag)
    end
  else
    timekey = if @chunk_key_time
                time_int = time.to_i
                (time_int - (time_int % @buffer_config.timekey)).to_i
              else
                nil
              end
    pairs = Hash[@chunk_keys.map{|k| [k.to_sym, record[k]]}]
    @buffer.metadata(timekey: timekey, tag: (@chunk_key_tag ? tag : nil), variables: pairs)
  end
end
metadata_for_test(tag, time, record) click to toggle source
# File lib/fluent/plugin/output.rb, line 781
def metadata_for_test(tag, time, record)
  raise "BUG: #metadata_for_test is available only when no actual metadata exists" unless @buffer.metadata_list.empty?
  m = metadata(tag, time, record)
  @buffer.metadata_list_clear!
  m
end
multi_workers_ready?() click to toggle source
# File lib/fluent/plugin/output.rb, line 143
def multi_workers_ready?
  false
end
next_flush_time() click to toggle source
# File lib/fluent/plugin/output.rb, line 991
def next_flush_time
  if @buffer.queued?
    @retry_mutex.synchronize do
      @retry ? @retry.next_time : Time.now + @buffer_config.flush_thread_burst_interval
    end
  else
    Time.now + @buffer_config.flush_thread_interval
  end
end
placeholder_validate!(name, str) click to toggle source
# File lib/fluent/plugin/output.rb, line 528
def placeholder_validate!(name, str)
  placeholder_validators(name, str).each do |v|
    v.validate!
  end
end
placeholder_validators(name, str, time_key = (@chunk_key_time && @buffer_config.timekey), tag_key = @chunk_key_tag, chunk_keys = @chunk_keys) click to toggle source
# File lib/fluent/plugin/output.rb, line 534
def placeholder_validators(name, str, time_key = (@chunk_key_time && @buffer_config.timekey), tag_key = @chunk_key_tag, chunk_keys = @chunk_keys)
  validators = []

  sec, title, example = get_placeholders_time(str)
  if sec || time_key
    validators << PlaceholderValidator.new(name, str, :time, {sec: sec, title: title, example: example, timekey: time_key})
  end

  parts = get_placeholders_tag(str)
  if tag_key || !parts.empty?
    validators << PlaceholderValidator.new(name, str, :tag, {parts: parts, tagkey: tag_key})
  end

  keys = get_placeholders_keys(str)
  if chunk_keys && !chunk_keys.empty? || !keys.empty?
    validators << PlaceholderValidator.new(name, str, :keys, {keys: keys, chunkkeys: chunk_keys})
  end

  validators
end
prefer_buffered_processing() click to toggle source
# File lib/fluent/plugin/output.rb, line 131
def prefer_buffered_processing
  # override this method to return false only when all of these are true:
  #  * plugin has both implementation for buffered and non-buffered methods
  #  * plugin is expected to work as non-buffered plugin if no `<buffer>` sections specified
  true
end
prefer_delayed_commit() click to toggle source
# File lib/fluent/plugin/output.rb, line 138
def prefer_delayed_commit
  # override this method to decide which is used of `write` or `try_write` if both are implemented
  true
end
process(tag, es) click to toggle source
# File lib/fluent/plugin/output.rb, line 108
def process(tag, es)
  raise NotImplementedError, "BUG: output plugins MUST implement this method"
end
retry_state(randomize) click to toggle source
# File lib/fluent/plugin/output.rb, line 1111
def retry_state(randomize)
  if @secondary
    retry_state_create(
      :output_retries, @buffer_config.retry_type, @buffer_config.retry_wait, @buffer_config.retry_timeout,
      forever: @buffer_config.retry_forever, max_steps: @buffer_config.retry_max_times, backoff_base: @buffer_config.retry_exponential_backoff_base,
      max_interval: @buffer_config.retry_max_interval,
      secondary: true, secondary_threshold: @buffer_config.retry_secondary_threshold,
      randomize: randomize
    )
  else
    retry_state_create(
      :output_retries, @buffer_config.retry_type, @buffer_config.retry_wait, @buffer_config.retry_timeout,
      forever: @buffer_config.retry_forever, max_steps: @buffer_config.retry_max_times, backoff_base: @buffer_config.retry_exponential_backoff_base,
      max_interval: @buffer_config.retry_max_interval,
      randomize: randomize
    )
  end
end
rollback_write(chunk_id) click to toggle source
# File lib/fluent/plugin/output.rb, line 943
def rollback_write(chunk_id)
  # This API is to rollback chunks explicitly from plugins.
  # 3rd party plugins can depend it on automatic rollback of #try_rollback_write
  @dequeued_chunks_mutex.synchronize do
    @dequeued_chunks.delete_if{ |info| info.chunk_id == chunk_id }
  end
  # returns true if chunk was rollbacked as expected
  #         false if chunk was already flushed and couldn't be rollbacked unexpectedly
  # in many cases, false can be just ignored
  if @buffer.takeback_chunk(chunk_id)
    @counters_monitor.synchronize{ @rollback_count += 1 }
    primary = @as_secondary ? @primary_instance : self
    primary.update_retry_state(chunk_id, @as_secondary)
    true
  else
    false
  end
end
shutdown() click to toggle source
Calls superclass method Fluent::Plugin::Base#shutdown
# File lib/fluent/plugin/output.rb, line 462
def shutdown
  @secondary.shutdown if @secondary
  @buffer.shutdown if @buffering && @buffer

  super
end
start() click to toggle source
Calls superclass method Fluent::Plugin::Base#start
# File lib/fluent/plugin/output.rb, line 353
def start
  super

  if @buffering.nil?
    @buffering = prefer_buffered_processing
    if !@buffering && @buffer
      @buffer.terminate # it's not started, so terminate will be enough
      # At here, this plugin works as non-buffered plugin.
      # Un-assign @buffer not to show buffering metrics (e.g., in_monitor_agent)
      @buffer = nil
    end
  end

  if @buffering
    m = method(:emit_buffered)
    (class << self; self; end).module_eval do
      define_method(:emit_events, m)
    end

    @custom_format = implement?(:custom_format)
    @enable_msgpack_streamer = @custom_format ? formatted_to_msgpack_binary : true
    @delayed_commit = if implement?(:buffered) && implement?(:delayed_commit)
                        prefer_delayed_commit
                      else
                        implement?(:delayed_commit)
                      end
    @delayed_commit_timeout = @buffer_config.delayed_commit_timeout
  else # !@buffering
    m = method(:emit_sync)
    (class << self; self; end).module_eval do
      define_method(:emit_events, m)
    end
  end

  if @buffering && !@as_secondary
    @retry = nil
    @retry_mutex = Mutex.new

    @buffer.start

    @output_enqueue_thread = nil
    @output_enqueue_thread_running = true

    @output_flush_threads = []
    @output_flush_threads_mutex = Mutex.new
    @output_flush_threads_running = true

    # mainly for test: detect enqueue works as code below:
    #   @output.interrupt_flushes
    #   # emits
    #   @output.enqueue_thread_wait
    @output_flush_interrupted = false
    @output_enqueue_thread_mutex = Mutex.new
    @output_enqueue_thread_waiting = false

    @dequeued_chunks = []
    @dequeued_chunks_mutex = Mutex.new

    @buffer_config.flush_thread_count.times do |i|
      thread_title = "flush_thread_#{i}".to_sym
      thread_state = FlushThreadState.new(nil, nil)
      thread = thread_create(thread_title) do
        flush_thread_run(thread_state)
      end
      thread_state.thread = thread
      @output_flush_threads_mutex.synchronize do
        @output_flush_threads << thread_state
      end
    end
    @output_flush_thread_current_position = 0

    if !@under_plugin_development && (@flush_mode == :interval || @chunk_key_time)
      @output_enqueue_thread = thread_create(:enqueue_thread, &method(:enqueue_thread_run))
    end
  end
  @secondary.start if @secondary
end
stop() click to toggle source
Calls superclass method Fluent::Plugin::Base#stop
# File lib/fluent/plugin/output.rb, line 436
def stop
  @secondary.stop if @secondary
  @buffer.stop if @buffering && @buffer

  super
end
submit_flush_all() click to toggle source
# File lib/fluent/plugin/output.rb, line 1149
def submit_flush_all
  while !@retry && @buffer.queued?
    submit_flush_once
    sleep @buffer_config.flush_thread_burst_interval
  end
end
submit_flush_once() click to toggle source
# File lib/fluent/plugin/output.rb, line 1130
def submit_flush_once
  # Without locks: it is rough but enough to select "next" writer selection
  @output_flush_thread_current_position = (@output_flush_thread_current_position + 1) % @buffer_config.flush_thread_count
  state = @output_flush_threads[@output_flush_thread_current_position]
  state.next_clock = 0
  if state.thread && state.thread.status # "run"/"sleep"/"aborting" or false(successfully stop) or nil(killed by exception)
    state.thread.run
  else
    log.warn "thread is already dead"
  end
end
support_in_v12_style?(feature) click to toggle source
# File lib/fluent/plugin/output.rb, line 504
def support_in_v12_style?(feature)
  # for plugins written in v0.12 styles
  case feature
  when :synchronous    then false
  when :buffered       then false
  when :delayed_commit then false
  when :custom_format  then false
  else
    raise ArgumentError, "unknown feature: #{feature}"
  end
end
terminate() click to toggle source
Calls superclass method Fluent::PluginLoggerMixin#terminate
# File lib/fluent/plugin/output.rb, line 497
def terminate
  @buffer.terminate if @buffering && @buffer
  @secondary.terminate if @secondary

  super
end
try_flush() click to toggle source
# File lib/fluent/plugin/output.rb, line 1001
def try_flush
  chunk = @buffer.dequeue_chunk
  return unless chunk

  log.trace "trying flush for a chunk", chunk: dump_unique_id_hex(chunk.unique_id)

  output = self
  using_secondary = false
  if @retry_mutex.synchronize{ @retry && @retry.secondary? }
    output = @secondary
    using_secondary = true
  end

  if @enable_msgpack_streamer
    chunk.extend ChunkMessagePackEventStreamer
  end

  begin
    chunk_write_start = Fluent::Clock.now

    if output.delayed_commit
      log.trace "executing delayed write and commit", chunk: dump_unique_id_hex(chunk.unique_id)
      @counters_monitor.synchronize{ @write_count += 1 }
      @dequeued_chunks_mutex.synchronize do
        # delayed_commit_timeout for secondary is configured in <buffer> of primary (<secondary> don't get <buffer>)
        @dequeued_chunks << DequeuedChunkInfo.new(chunk.unique_id, Time.now, self.delayed_commit_timeout)
      end

      output.try_write(chunk)
      check_slow_flush(chunk_write_start)
    else # output plugin without delayed purge
      chunk_id = chunk.unique_id
      dump_chunk_id = dump_unique_id_hex(chunk_id)
      log.trace "adding write count", instance: self.object_id
      @counters_monitor.synchronize{ @write_count += 1 }
      log.trace "executing sync write", chunk: dump_chunk_id

      output.write(chunk)
      check_slow_flush(chunk_write_start)

      log.trace "write operation done, committing", chunk: dump_chunk_id
      commit_write(chunk_id, delayed: false, secondary: using_secondary)
      log.trace "done to commit a chunk", chunk: dump_chunk_id
    end
  rescue => e
    log.debug "taking back chunk for errors.", chunk: dump_unique_id_hex(chunk.unique_id)
    if output.delayed_commit
      @dequeued_chunks_mutex.synchronize do
        @dequeued_chunks.delete_if{|d| d.chunk_id == chunk.unique_id }
      end
    end
    @buffer.takeback_chunk(chunk.unique_id)

    update_retry_state(chunk.unique_id, using_secondary, e)

    raise if @under_plugin_development && !@retry_for_error_chunk
  end
end
try_rollback_all() click to toggle source
# File lib/fluent/plugin/output.rb, line 976
def try_rollback_all
  return unless @dequeued_chunks
  @dequeued_chunks_mutex.synchronize do
    until @dequeued_chunks.empty?
      info = @dequeued_chunks.shift
      if @buffer.takeback_chunk(info.chunk_id)
        @counters_monitor.synchronize{ @rollback_count += 1 }
        log.info "delayed commit for buffer chunks was cancelled in shutdown", chunk_id: dump_unique_id_hex(info.chunk_id)
        primary = @as_secondary ? @primary_instance : self
        primary.update_retry_state(info.chunk_id, @as_secondary)
      end
    end
  end
end
try_rollback_write() click to toggle source
# File lib/fluent/plugin/output.rb, line 962
def try_rollback_write
  @dequeued_chunks_mutex.synchronize do
    while @dequeued_chunks.first && @dequeued_chunks.first.expired?
      info = @dequeued_chunks.shift
      if @buffer.takeback_chunk(info.chunk_id)
        @counters_monitor.synchronize{ @rollback_count += 1 }
        log.warn "failed to flush the buffer chunk, timeout to commit.", chunk_id: dump_unique_id_hex(info.chunk_id), flushed_at: info.time
        primary = @as_secondary ? @primary_instance : self
        primary.update_retry_state(info.chunk_id, @as_secondary)
      end
    end
  end
end
try_write(chunk) click to toggle source
# File lib/fluent/plugin/output.rb, line 116
def try_write(chunk)
  raise NotImplementedError, "BUG: output plugins MUST implement this method"
end
update_retry_state(chunk_id, using_secondary, error = nil) click to toggle source
# File lib/fluent/plugin/output.rb, line 1068
def update_retry_state(chunk_id, using_secondary, error = nil)
  @retry_mutex.synchronize do
    @counters_monitor.synchronize{ @num_errors += 1 }
    chunk_id_hex = dump_unique_id_hex(chunk_id)

    unless @retry
      @retry = retry_state(@buffer_config.retry_randomize)
      if error
        log.warn "failed to flush the buffer.", retry_time: @retry.steps, next_retry_seconds: @retry.next_time, chunk: chunk_id_hex, error: error
        log.warn_backtrace error.backtrace
      end
      return
    end

    # @retry exists

    if error
      if @retry.limit?
        records = @buffer.queued_records
        msg = "failed to flush the buffer, and hit limit for retries. dropping all chunks in the buffer queue."
        log.error msg, retry_times: @retry.steps, records: records, error: error
        log.error_backtrace error.backtrace
      elsif using_secondary
        msg = "failed to flush the buffer with secondary output."
        log.warn msg, retry_time: @retry.steps, next_retry_seconds: @retry.next_time, chunk: chunk_id_hex, error: error
        log.warn_backtrace error.backtrace
      else
        msg = "failed to flush the buffer."
        log.warn msg, retry_time: @retry.steps, next_retry_seconds: @retry.next_time, chunk: chunk_id_hex, error: error
        log.warn_backtrace error.backtrace
      end
    end

    if @retry.limit?
      @buffer.clear_queue!
      log.debug "buffer queue cleared"
      @retry = nil
    else
      @retry.step
    end
  end
end
write(chunk) click to toggle source
# File lib/fluent/plugin/output.rb, line 112
def write(chunk)
  raise NotImplementedError, "BUG: output plugins MUST implement this method"
end
write_guard(&block) click to toggle source
# File lib/fluent/plugin/output.rb, line 798
def write_guard(&block)
  begin
    block.call
  rescue Fluent::Plugin::Buffer::BufferOverflowError
    log.warn "failed to write data into buffer by buffer overflow", action: @buffer_config.overflow_action
    case @buffer_config.overflow_action
    when :throw_exception
      raise
    when :block
      log.debug "buffer.write is now blocking"
      until @buffer.storable?
        if self.stopped?
          log.error "breaking block behavior to shutdown Fluentd"
          # to break infinite loop to exit Fluentd process
          raise
        end
        log.trace "sleeping until buffer can store more data"
        sleep 1
      end
      log.debug "retrying buffer.write after blocked operation"
      retry
    when :drop_oldest_chunk
      begin
        oldest = @buffer.dequeue_chunk
        if oldest
          log.warn "dropping oldest chunk to make space after buffer overflow", chunk_id: oldest.unique_id
          @buffer.purge_chunk(oldest.unique_id)
        else
          log.error "no queued chunks to be dropped for drop_oldest_chunk"
        end
      rescue
        # ignore any errors
      end
      raise unless @buffer.storable?
      retry
    else
      raise "BUG: unknown overflow_action '#{@buffer_config.overflow_action}'"
    end
  end
end