Class: Fluent::Plugin::Output

Inherits:
Base
  • Object
show all
Includes:
Fluent::PluginHelper::Mixin, Fluent::PluginId, Fluent::PluginLoggerMixin, UniqueId::Mixin
Defined in:
lib/fluent/plugin/output.rb

Defined Under Namespace

Classes: DequeuedChunkInfo, FlushThreadState, PlaceholderValidator

Constant Summary collapse

CHUNK_KEY_PATTERN = 
/^[-_.@a-zA-Z0-9]+$/
CHUNK_KEY_PLACEHOLDER_PATTERN = 
/\$\{([-_.@$a-zA-Z0-9]+)\}/
CHUNK_TAG_PLACEHOLDER_PATTERN = 
/\$\{(tag(?:\[-?\d+\])?)\}/
CHUNK_ID_PLACEHOLDER_PATTERN = 
/\$\{chunk_id\}/
CHUNKING_FIELD_WARN_NUM = 
4
TIME_KEY_PLACEHOLDER_THRESHOLDS = 
[
  [1, :second, '%S'],
  [60, :minute, '%M'],
  [3600, :hour, '%H'],
  [86400, :day, '%d'],
]
TIMESTAMP_CHECK_BASE_TIME = 
Time.parse("2016-01-01 00:00:00 UTC")
FORMAT_MSGPACK_STREAM = 
->(e){ e.to_msgpack_stream(packer: Fluent::MessagePackFactory.thread_local_msgpack_packer) }
FORMAT_COMPRESSED_MSGPACK_STREAM = 
->(e){ e.to_compressed_msgpack_stream(packer: Fluent::MessagePackFactory.thread_local_msgpack_packer) }
FORMAT_MSGPACK_STREAM_TIME_INT = 
->(e){ e.to_msgpack_stream(time_int: true, packer: Fluent::MessagePackFactory.thread_local_msgpack_packer) }
FORMAT_COMPRESSED_MSGPACK_STREAM_TIME_INT = 
->(e){ e.to_compressed_msgpack_stream(time_int: true, packer: Fluent::MessagePackFactory.thread_local_msgpack_packer) }
UNRECOVERABLE_ERRORS = 
[Fluent::UnrecoverableError, TypeError, ArgumentError, NoMethodError, MessagePack::UnpackError, EncodingError]
BUFFER_STATS_KEYS = 
{}

Constants included from Configurable

Configurable::CONFIG_TYPE_REGISTRY

Instance Attribute Summary collapse

Attributes included from Fluent::PluginLoggerMixin

#log

Attributes inherited from Base

#under_plugin_development

Instance Method Summary collapse

Methods included from UniqueId::Mixin

#dump_unique_id_hex, #generate_unique_id

Methods included from Fluent::PluginHelper::Mixin

included

Methods included from Fluent::PluginLoggerMixin

included

Methods included from Fluent::PluginId

#plugin_id, #plugin_id_configured?, #plugin_id_for_test?, #plugin_root_dir

Methods inherited from Base

#acquire_worker_lock, #after_shutdown?, #after_started?, #before_shutdown?, #called_in_test?, #closed?, #configured?, #context_router, #context_router=, #fluentd_worker_id, #get_lock_path, #has_router?, #inspect, #plugin_root_dir, #reloadable_plugin?, #shutdown?, #started?, #stopped?, #string_safe_encoding, #terminated?

Methods included from SystemConfig::Mixin

#system_config, #system_config_override

Methods included from Configurable

#config, #configure_proxy_generate, #configured_section_create, included, lookup_type, register_type

Constructor Details

#initialize ⇒ Output

Returns a new instance of Output.



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# File 'lib/fluent/plugin/output.rb', line 199

def initialize
  super
  @counter_mutex = Mutex.new
  @buffering = false
  @delayed_commit = false
  @as_secondary = false
  @primary_instance = nil

  # TODO: well organized counters
  @num_errors_metrics = nil
  @emit_count_metrics = nil
  @emit_records_metrics = nil
  @emit_size_metrics = nil
  @write_count_metrics = nil
  @rollback_count_metrics = nil
  @flush_time_count_metrics = nil
  @slow_flush_count_metrics = nil
  @enable_size_metrics = false

  # 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
  @output_flush_thread_current_position = 0

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

  @retry_for_error_chunk = false
end

Instance Attribute Details

#as_secondary ⇒ Object (readonly)

Returns the value of attribute as_secondary.



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# File 'lib/fluent/plugin/output.rb', line 167

def as_secondary
  @as_secondary
end

#buffer ⇒ Object (readonly)

for tests



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# File 'lib/fluent/plugin/output.rb', line 170

def buffer
  @buffer
end

#chunk_key_accessors ⇒ Object (readonly)

for tests



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# File 'lib/fluent/plugin/output.rb', line 170

def chunk_key_accessors
  @chunk_key_accessors
end

#chunk_key_tag ⇒ Object (readonly)

for tests



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# File 'lib/fluent/plugin/output.rb', line 170

def chunk_key_tag
  @chunk_key_tag
end

#chunk_key_time ⇒ Object (readonly)

for tests



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# File 'lib/fluent/plugin/output.rb', line 170

def chunk_key_time
  @chunk_key_time
end

#chunk_keys ⇒ Object (readonly)

for tests



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# File 'lib/fluent/plugin/output.rb', line 170

def chunk_keys
  @chunk_keys
end

#delayed_commit ⇒ Object (readonly)

Returns the value of attribute delayed_commit.



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# File 'lib/fluent/plugin/output.rb', line 167

def delayed_commit
  @delayed_commit
end

#delayed_commit_timeout ⇒ Object (readonly)

Returns the value of attribute delayed_commit_timeout.



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# File 'lib/fluent/plugin/output.rb', line 167

def delayed_commit_timeout
  @delayed_commit_timeout
end

#dequeued_chunks ⇒ Object

Returns the value of attribute dequeued_chunks.



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# File 'lib/fluent/plugin/output.rb', line 171

def dequeued_chunks
  @dequeued_chunks
end

#dequeued_chunks_mutex ⇒ Object

Returns the value of attribute dequeued_chunks_mutex.



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# File 'lib/fluent/plugin/output.rb', line 171

def dequeued_chunks_mutex
  @dequeued_chunks_mutex
end

#output_enqueue_thread_waiting ⇒ Object

Returns the value of attribute output_enqueue_thread_waiting.



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# File 'lib/fluent/plugin/output.rb', line 171

def output_enqueue_thread_waiting
  @output_enqueue_thread_waiting
end

#retry ⇒ Object (readonly)

for tests



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# File 'lib/fluent/plugin/output.rb', line 170

def retry
  @retry
end

#retry_for_error_chunk ⇒ Object

output_enqueue_thread_waiting: for test of output.rb itself



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# File 'lib/fluent/plugin/output.rb', line 173

def retry_for_error_chunk
  @retry_for_error_chunk
end

#secondary ⇒ Object (readonly)

for tests



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# File 'lib/fluent/plugin/output.rb', line 170

def secondary
  @secondary
end

#timekey_zone ⇒ Object (readonly)

Returns the value of attribute timekey_zone.



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# File 'lib/fluent/plugin/output.rb', line 167

def timekey_zone
  @timekey_zone
end

Instance Method Details

#acts_as_secondary(primary) ⇒ Object 



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# File 'lib/fluent/plugin/output.rb', line 248

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

  singleton_class.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, update_retry: true| @primary_instance.rollback_write(chunk_id, update_retry) }
  end
end

#after_shutdown ⇒ Object 



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# File 'lib/fluent/plugin/output.rb', line 554

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|
        # to wakeup thread and make it to stop by itself
        state.mutex.synchronize {
          if state.thread && state.thread.status
            state.next_clock = 0
            state.cond_var.signal
          end
        }
        Thread.pass
        state.thread.join
      end
    end
  end

  super
end

#after_start ⇒ Object 



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# File 'lib/fluent/plugin/output.rb', line 516

def after_start
  super
  @secondary.after_start if @secondary
end

#backup_chunk(chunk, using_secondary, delayed_commit) ⇒ Object 



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# File 'lib/fluent/plugin/output.rb', line 1242

def backup_chunk(chunk, using_secondary, delayed_commit)
  if @buffer_config.disable_chunk_backup
    log.warn "disable_chunk_backup is true. #{dump_unique_id_hex(chunk.unique_id)} chunk is thrown away"
  else
    unique_id = dump_unique_id_hex(chunk.unique_id)
    safe_plugin_id = plugin_id.gsub(/[ "\/\\:;|*<>?]/, '_')
    backup_base_dir = system_config.root_dir || DEFAULT_BACKUP_DIR
    backup_file = File.join(backup_base_dir, 'backup', "worker#{fluentd_worker_id}", safe_plugin_id, "#{unique_id}.log")
    backup_dir = File.dirname(backup_file)

    log.warn "bad chunk is moved to #{backup_file}"
    FileUtils.mkdir_p(backup_dir, mode: system_config.dir_permission || Fluent::DEFAULT_DIR_PERMISSION) unless Dir.exist?(backup_dir)
    File.open(backup_file, 'ab', system_config.file_permission || Fluent::DEFAULT_FILE_PERMISSION) { |f|
      chunk.write_to(f)
    }
  end
  commit_write(chunk.unique_id, secondary: using_secondary, delayed: delayed_commit)
end

#before_shutdown ⇒ Object 



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# File 'lib/fluent/plugin/output.rb', line 528

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

#calculate_timekey(time) ⇒ Object 



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# File 'lib/fluent/plugin/output.rb', line 903

def calculate_timekey(time)
  time_int = time.to_i
  if @timekey_use_utc
    (time_int - (time_int % @timekey)).to_i
  else
    offset = @calculate_offset ? @calculate_offset.call(time) : @offset
    (time_int - ((time_int + offset)% @timekey)).to_i
  end
end

#check_slow_flush(start) ⇒ Object 



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# File 'lib/fluent/plugin/output.rb', line 1261

def check_slow_flush(start)
  elapsed_time = Fluent::Clock.now - start
  elapsed_millsec = (elapsed_time * 1000).to_i
  @flush_time_count_metrics.add(elapsed_millsec)
  if elapsed_time > @slow_flush_log_threshold
    @slow_flush_count_metrics.inc
    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

#chunk_for_test(tag, time, record) ⇒ Object 



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# File 'lib/fluent/plugin/output.rb', line 913

def chunk_for_test(tag, time, record)
  require 'fluent/plugin/buffer/memory_chunk'

  m = metadata(tag, time, record)
  Fluent::Plugin::Buffer::MemoryChunk.new(m)
end

#close ⇒ Object 



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# File 'lib/fluent/plugin/output.rb', line 580

def close
  @buffer.close if @buffering && @buffer
  @secondary.close if @secondary

  super
end

#commit_write(chunk_id, delayed: @delayed_commit, secondary: false) ⇒ Object 



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# File 'lib/fluent/plugin/output.rb', line 1057

def commit_write(chunk_id, delayed: @delayed_commit, secondary: false)
  log.on_trace { 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) ⇒ Object 



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# File 'lib/fluent/plugin/output.rb', line 266

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

  @num_errors_metrics = metrics_create(namespace: "fluentd", subsystem: "output", name: "num_errors", help_text: "Number of count num errors")
  @emit_count_metrics = metrics_create(namespace: "fluentd", subsystem: "output", name: "emit_count", help_text: "Number of count emits")
  @emit_records_metrics = metrics_create(namespace: "fluentd", subsystem: "output", name: "emit_records", help_text: "Number of emit records")
  @emit_size_metrics =  metrics_create(namespace: "fluentd", subsystem: "output", name: "emit_size", help_text: "Total size of emit events")
  @write_count_metrics = metrics_create(namespace: "fluentd", subsystem: "output", name: "write_count", help_text: "Number of writing events")
  @rollback_count_metrics = metrics_create(namespace: "fluentd", subsystem: "output", name: "rollback_count", help_text: "Number of rollbacking operations")
  @flush_time_count_metrics = metrics_create(namespace: "fluentd", subsystem: "output", name: "flush_time_count", help_text: "Count of flush time")
  @slow_flush_count_metrics = metrics_create(namespace: "fluentd", subsystem: "output", name: "slow_flush_count", help_text: "Count of slow flush occurred time(s)")

  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
  # Enable to update record size metrics or not
  @enable_size_metrics = !!system_config.enable_size_metrics

  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|
        begin
          k = Fluent::PluginHelper::RecordAccessor::Accessor.parse_parameter(key)
          if k.is_a?(String)
            k !~ CHUNK_KEY_PATTERN
          else
            if key.start_with?('$[')
              raise Fluent::ConfigError, "in chunk_keys: bracket notation is not allowed"
            else
              false
            end
          end
        rescue => e
          raise Fluent::ConfigError, "in chunk_keys: #{e.message}"
        end
      }
      raise Fluent::ConfigError, "chunk_keys specification includes invalid char"
    else
      @chunk_key_accessors = Hash[@chunk_keys.map { |key| [key.to_sym, Fluent::PluginHelper::RecordAccessor::Accessor.new(key)] }]
    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
      @timekey = @buffer_config.timekey
      if @timekey <= 0
        raise Fluent::ConfigError, "timekey should be greater than 0. current timekey: #{@timekey}"
      end
      @timekey_use_utc = @buffer_config.timekey_use_utc
      @offset = Fluent::Timezone.utc_offset(@timekey_zone)
      @calculate_offset = @offset.respond_to?(:call) ? @offset : nil
      @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)
    @buffer.enable_update_timekeys if @chunk_key_time

    @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

    if @buffer.queued_chunks_limit_size.nil?
      @buffer.queued_chunks_limit_size = @buffer_config.flush_thread_count
    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
    if @buffer_config.retry_forever
      log.warn "<secondary> with 'retry_forever', only unrecoverable errors are moved to secondary"
    end

    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)
    unless @secondary.respond_to?(:acts_as_secondary)
      raise Fluent::ConfigError, "Failed to setup secondary plugin in '#{conf['@type']}'. '#{secondary_type}' plugin in not allowed due to non buffered output"
    end
    @secondary.acts_as_secondary(self)
    @secondary.configure(secondary_conf)
    if (self.class != @secondary.class) && (@custom_format || @secondary.implement?(:custom_format))
      log.warn "Use different plugin for secondary. Check the plugin works with primary like secondary_file", primary: self.class.to_s, secondary: @secondary.class.to_s
    end
  else
    @secondary = nil
  end

  self
end

#emit_buffered(tag, es) ⇒ Object 



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# File 'lib/fluent/plugin/output.rb', line 849

def emit_buffered(tag, es)
  @emit_count_metrics.inc
  begin
    execute_chunking(tag, es, enqueue: (@flush_mode == :immediate))
    if !@retry && @buffer.queued?(nil, optimistic: true)
      submit_flush_once
    end
  rescue
    # TODO: separate number of errors into emit errors and write/flush errors
    @num_errors_metrics.inc
    raise
  end
end

#emit_count ⇒ Object 



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# File 'lib/fluent/plugin/output.rb', line 179

def emit_count
  @emit_count_metrics.get
end

#emit_events(tag, es) ⇒ Object 



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# File 'lib/fluent/plugin/output.rb', line 828

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_records ⇒ Object 



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# File 'lib/fluent/plugin/output.rb', line 187

def emit_records
  @emit_records_metrics.get
end

#emit_size ⇒ Object 



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# File 'lib/fluent/plugin/output.rb', line 183

def emit_size
  @emit_size_metrics.get
end

#emit_sync(tag, es) ⇒ Object 



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# File 'lib/fluent/plugin/output.rb', line 837

def emit_sync(tag, es)
  @emit_count_metrics.inc
  begin
    process(tag, es)
    @emit_records_metrics.add(es.size)
    @emit_size_metrics.add(es.to_msgpack_stream.bytesize) if @enable_size_metrics
  rescue
    @num_errors_metrics.inc
    raise
  end
end

#enqueue_thread_run ⇒ Object 



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# File 'lib/fluent/plugin/output.rb', line 1408

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, @buffer_config.timekey_wait].min
    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.raw_create_at + 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 ⇒ Object

only for tests of output plugin



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# File 'lib/fluent/plugin/output.rb', line 1384

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) ⇒ Object 



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# File 'lib/fluent/plugin/output.rb', line 920

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, chunk) ⇒ Object

TODO: optimize this code



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# File 'lib/fluent/plugin/output.rb', line 753

def extract_placeholders(str, chunk)
  metadata = if chunk.is_a?(Fluent::Plugin::Buffer::Chunk)
               chunk_passed = true
               chunk.metadata
             else
               chunk_passed = false
               # For existing plugins. Old plugin passes Chunk.metadata instead of Chunk
               chunk
             end
  if metadata.empty?
    str.sub(CHUNK_ID_PLACEHOLDER_PATTERN) {
      if chunk_passed
        dump_unique_id_hex(chunk.unique_id)
      else
        log.warn "${chunk_id} is not allowed in this plugin. Pass Chunk instead of metadata in extract_placeholders's 2nd argument"
      end
    }
  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]}, ... , ${tag[-2]}, ${tag[-1]}
    if @chunk_key_tag
      if str.include?('${tag}')
        rvalue = rvalue.gsub('${tag}', metadata.tag)
      end
      if str =~ CHUNK_TAG_PLACEHOLDER_PATTERN
        hash = {}
        tag_parts = metadata.tag.split('.')
        tag_parts.each_with_index do |part, i|
          hash["${tag[#{i}]}"] = part
          hash["${tag[#{i-tag_parts.size}]}"] = 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

    # First we replace ${chunk_id} with chunk.unique_id (hexlified).
    rvalue = rvalue.sub(CHUNK_ID_PLACEHOLDER_PATTERN) {
      if chunk_passed
        dump_unique_id_hex(chunk.unique_id)
      else
        log.warn "${chunk_id} is not allowed in this plugin. Pass Chunk instead of metadata in extract_placeholders's 2nd argument"
      end
    }

    # Then, replace other ${chunk_key}s.
    if !@chunk_keys.empty? && metadata.variables
      hash = {'${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) do |matched|
        hash.fetch(matched) do
          log.warn "chunk key placeholder '#{matched[2..-2]}' not replaced. template:#{str}"
          ''
        end
      end
    end

    if rvalue =~ CHUNK_KEY_PLACEHOLDER_PATTERN
      log.warn "chunk key placeholder '#{$1}' not replaced. template:#{str}"
    end

    rvalue
  end
end

#flush_thread_run(state) ⇒ Object 



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# File 'lib/fluent/plugin/output.rb', line 1473

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"

  state.mutex.lock
  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
      next_retry_time = nil

      @retry_mutex.synchronize do
        next_retry_time = @retry ? @retry.next_time : nil
      end

      if state.next_clock > current_clock
        interval = state.next_clock - current_clock
      elsif next_retry_time && next_retry_time > Time.now
        interval = next_retry_time.to_f - Time.now.to_f
      else
        state.mutex.unlock
        begin
          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
        ensure
          state.mutex.lock
        end
      end

      if @dequeued_chunks_mutex.synchronize{ !@dequeued_chunks.empty? && @dequeued_chunks.first.expired? }
        unless @output_flush_interrupted
          state.mutex.unlock
          begin
            try_rollback_write
          ensure
            state.mutex.lock
          end
        end
      end

      state.cond_var.wait(state.mutex, 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
  ensure
    state.mutex.unlock
  end
end

#flush_thread_wakeup ⇒ Object

only for tests of output plugin



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# File 'lib/fluent/plugin/output.rb', line 1396

def flush_thread_wakeup
  @output_flush_threads.each do |state|
    state.mutex.synchronize {
      if state.thread && state.thread.status
        state.next_clock = 0
        state.cond_var.signal
      end
    }
    Thread.pass
  end
end

#force_flush ⇒ Object 



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# File 'lib/fluent/plugin/output.rb', line 1364

def force_flush
  if @buffering
    @buffer.enqueue_all(true)
    submit_flush_all
  end
end

#format(tag, time, record) ⇒ Object

Raises:

  • (NotImplementedError) 


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# File 'lib/fluent/plugin/output.rb', line 127

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 ⇒ Object

Compatibility for existing plugins



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# File 'lib/fluent/plugin/output.rb', line 139

def formatted_to_msgpack_binary
  formatted_to_msgpack_binary?
end

#formatted_to_msgpack_binary? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/fluent/plugin/output.rb', line 132

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 ⇒ Object 



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# File 'lib/fluent/plugin/output.rb', line 976

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) ⇒ Object 



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# File 'lib/fluent/plugin/output.rb', line 748

def get_placeholders_keys(str)
  str.scan(CHUNK_KEY_PLACEHOLDER_PATTERN).map(&:first).reject{|s| (s == "tag") || (s == 'chunk_id') }.sort
end

#get_placeholders_tag(str) ⇒ Object

-1 means whole tag



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# File 'lib/fluent/plugin/output.rb', line 735

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) ⇒ Object

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



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# File 'lib/fluent/plugin/output.rb', line 725

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_limit_reached(error) ⇒ Object 



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# File 'lib/fluent/plugin/output.rb', line 1318

def handle_limit_reached(error)
  if error
    records = @buffer.queued_records
    msg = "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
  end
  @buffer.clear_queue!
  log.debug "buffer queue cleared"
  @retry = nil
end

#handle_stream_simple(tag, es, enqueue: false) ⇒ Object 



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# File 'lib/fluent/plugin/output.rb', line 1031

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(unpacker: Fluent::MessagePackFactory.thread_local_msgpack_unpacker) 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
  @emit_records_metrics.add(es.size)
  @emit_size_metrics.add(es.to_msgpack_stream.bytesize) if @enable_size_metrics
  true
end

#handle_stream_with_custom_format(tag, es, enqueue: false) ⇒ Object

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.



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# File 'lib/fluent/plugin/output.rb', line 993

def handle_stream_with_custom_format(tag, es, enqueue: false)
  meta_and_data = {}
  records = 0
  es.each(unpacker: Fluent::MessagePackFactory.thread_local_msgpack_unpacker) 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
  @emit_records_metrics.add(es.size)
  @emit_size_metrics.add(es.to_msgpack_stream.bytesize) if @enable_size_metrics
  true
end

#handle_stream_with_standard_format(tag, es, enqueue: false) ⇒ Object 



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# File 'lib/fluent/plugin/output.rb', line 1013

def handle_stream_with_standard_format(tag, es, enqueue: false)
  format_proc = generate_format_proc
  meta_and_data = {}
  records = 0
  es.each(unpacker: Fluent::MessagePackFactory.thread_local_msgpack_unpacker) 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
  @emit_records_metrics.add(es.size)
  @emit_size_metrics.add(es.to_msgpack_stream.bytesize) if @enable_size_metrics
  true
end

#implement?(feature) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/fluent/plugin/output.rb', line 606

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 ⇒ Object

only for tests of output plugin



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# File 'lib/fluent/plugin/output.rb', line 1379

def interrupt_flushes
  @output_flush_interrupted = true
end

#log_retry_error(error, chunk_id_hex, using_secondary) ⇒ Object 



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# File 'lib/fluent/plugin/output.rb', line 1307

def log_retry_error(error, chunk_id_hex, using_secondary)
  return unless error
  if using_secondary
    msg = "failed to flush the buffer with secondary output."
  else
    msg = "failed to flush the buffer."
  end
  log.warn(msg, retry_times: @retry.steps, next_retry_time: @retry.next_time.round, chunk: chunk_id_hex, error: error)
  log.warn_backtrace(error.backtrace)
end

#metadata(tag, time, record) ⇒ Object

TODO: optimize this code

Raises:

  • (ArgumentError) 


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# File 'lib/fluent/plugin/output.rb', line 864

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
      timekey = calculate_timekey(time)
      @buffer.metadata(timekey: timekey, tag: tag)
    elsif @chunk_key_time
      timekey = calculate_timekey(time)
      @buffer.metadata(timekey: timekey)
    else
      @buffer.metadata(tag: tag)
    end
  else
    timekey = if @chunk_key_time
                calculate_timekey(time)
              else
                nil
              end
    pairs = Hash[@chunk_key_accessors.map { |k, a| [k, a.call(record)] }]
    @buffer.metadata(timekey: timekey, tag: (@chunk_key_tag ? tag : nil), variables: pairs)
  end
end

#multi_workers_ready? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/fluent/plugin/output.rb', line 155

def multi_workers_ready?
  false
end

#next_flush_time ⇒ Object 



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# File 'lib/fluent/plugin/output.rb', line 1131

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

#num_errors ⇒ Object 



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# File 'lib/fluent/plugin/output.rb', line 175

def num_errors
  @num_errors_metrics.get
end

#placeholder_validate!(name, str) ⇒ Object 



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# File 'lib/fluent/plugin/output.rb', line 618

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) ⇒ Object 



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# File 'lib/fluent/plugin/output.rb', line 624

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 ⇒ Object 



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# File 'lib/fluent/plugin/output.rb', line 143

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 ⇒ Object 



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# File 'lib/fluent/plugin/output.rb', line 150

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) ⇒ Object

Raises:

  • (NotImplementedError) 


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# File 'lib/fluent/plugin/output.rb', line 115

def process(tag, es)
  raise NotImplementedError, "BUG: output plugins MUST implement this method"
end

#retry_state(randomize) ⇒ Object 



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# File 'lib/fluent/plugin/output.rb', line 1330

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_count ⇒ Object 



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# File 'lib/fluent/plugin/output.rb', line 195

def rollback_count
  @rollback_count_metrics.get
end

#rollback_write(chunk_id, update_retry: true) ⇒ Object

update_retry parameter is for preventing busy loop by async write We will remove this parameter by re-design retry_state management between threads.



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# File 'lib/fluent/plugin/output.rb', line 1081

def rollback_write(chunk_id, update_retry: true)
  # 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)
    @rollback_count_metrics.inc
    if update_retry
      primary = @as_secondary ? @primary_instance : self
      primary.update_retry_state(chunk_id, @as_secondary)
    end
    true
  else
    false
  end
end

#shutdown ⇒ Object 



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# File 'lib/fluent/plugin/output.rb', line 547

def shutdown
  @secondary.shutdown if @secondary
  @buffer.shutdown if @buffering && @buffer

  super
end

#start ⇒ Object 



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# File 'lib/fluent/plugin/output.rb', line 438

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)
    singleton_class.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)
    singleton_class.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

    @output_flush_thread_current_position = 0
    @buffer_config.flush_thread_count.times do |i|
      thread_title = "flush_thread_#{i}".to_sym
      thread_state = FlushThreadState.new(nil, nil, Mutex.new, ConditionVariable.new)
      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

    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

#statistics ⇒ Object 



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# File 'lib/fluent/plugin/output.rb', line 1542

def statistics
  stats = {
    'emit_records' => @emit_records_metrics.get,
    'emit_size' => @emit_size_metrics.get,
    # Respect original name
    # https://github.com/fluent/fluentd/blob/45c7b75ba77763eaf87136864d4942c4e0c5bfcd/lib/fluent/plugin/in_monitor_agent.rb#L284
    'retry_count' => @num_errors_metrics.get,
    'emit_count' => @emit_count_metrics.get,
    'write_count' => @write_count_metrics.get,
    'rollback_count' => @rollback_count_metrics.get,
    'slow_flush_count' => @slow_flush_count_metrics.get,
    'flush_time_count' => @flush_time_count_metrics.get,
  }

  if @buffer && @buffer.respond_to?(:statistics)
    (@buffer.statistics['buffer'] || {}).each do |k, v|
      stats[BUFFER_STATS_KEYS[k]] = v
    end
  end

  { 'output' => stats }
end

#stop ⇒ Object 



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# File 'lib/fluent/plugin/output.rb', line 521

def stop
  @secondary.stop if @secondary
  @buffer.stop if @buffering && @buffer

  super
end

#submit_flush_all ⇒ Object 



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# File 'lib/fluent/plugin/output.rb', line 1371

def submit_flush_all
  while !@retry && @buffer.queued?
    submit_flush_once
    sleep @buffer_config.flush_thread_burst_interval
  end
end

#submit_flush_once ⇒ Object 



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# File 'lib/fluent/plugin/output.rb', line 1349

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.mutex.synchronize {
    if state.thread && state.thread.status # "run"/"sleep"/"aborting" or false(successfully stop) or nil(killed by exception)
      state.next_clock = 0
      state.cond_var.signal
    else
      log.warn "thread is already dead"
    end
  }
  Thread.pass
end

#support_in_v12_style?(feature) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/fluent/plugin/output.rb', line 594

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 ⇒ Object 



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# File 'lib/fluent/plugin/output.rb', line 587

def terminate
  @buffer.terminate if @buffering && @buffer
  @secondary.terminate if @secondary

  super
end

#try_flush ⇒ Object 



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# File 'lib/fluent/plugin/output.rb', line 1143

def try_flush
  chunk = @buffer.dequeue_chunk
  return unless chunk

  log.on_trace { 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)
      @write_count_metrics.inc
      @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
      @write_count_metrics.inc
      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 *UNRECOVERABLE_ERRORS => e
    if @secondary
      if using_secondary
        log.warn "got unrecoverable error in secondary.", error: e
        log.warn_backtrace
        backup_chunk(chunk, using_secondary, output.delayed_commit)
      else
        if (self.class == @secondary.class)
          log.warn "got unrecoverable error in primary and secondary type is same as primary. Skip secondary", error: e
          log.warn_backtrace
          backup_chunk(chunk, using_secondary, output.delayed_commit)
        else
          # Call secondary output directly without retry update.
          # In this case, delayed commit causes inconsistent state in dequeued chunks so async output in secondary is not allowed for now.
          if @secondary.delayed_commit
            log.warn "got unrecoverable error in primary and secondary is async output. Skip secondary for backup", error: e
            log.warn_backtrace
            backup_chunk(chunk, using_secondary, output.delayed_commit)
          else
            log.warn "got unrecoverable error in primary. Skip retry and flush chunk to secondary", error: e
            log.warn_backtrace
            begin
              @secondary.write(chunk)
              commit_write(chunk_id, delayed: output.delayed_commit, secondary: true)
            rescue => e
              log.warn "got an error in secondary for unrecoverable error", error: e
              log.warn_backtrace
              backup_chunk(chunk, using_secondary, output.delayed_commit)
            end
          end
        end
      end
    else
      log.warn "got unrecoverable error in primary and no secondary", error: e
      log.warn_backtrace
      backup_chunk(chunk, using_secondary, output.delayed_commit)
    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

    if @buffer.takeback_chunk(chunk.unique_id)
      @rollback_count_metrics.inc
    end

    update_retry_state(chunk.unique_id, using_secondary, e)

    raise if @under_plugin_development && !@retry_for_error_chunk
  end
end

#try_rollback_all ⇒ Object 



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# File 'lib/fluent/plugin/output.rb', line 1116

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)
        @rollback_count_metrics.inc
        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 ⇒ Object 



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# File 'lib/fluent/plugin/output.rb', line 1102

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)
        @rollback_count_metrics.inc
        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) ⇒ Object

Raises:

  • (NotImplementedError) 


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# File 'lib/fluent/plugin/output.rb', line 123

def try_write(chunk)
  raise NotImplementedError, "BUG: output plugins MUST implement this method"
end

#update_retry_state(chunk_id, using_secondary, error = nil) ⇒ Object 



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# File 'lib/fluent/plugin/output.rb', line 1272

def update_retry_state(chunk_id, using_secondary, error = nil)
  @retry_mutex.synchronize do
    @num_errors_metrics.inc
    chunk_id_hex = dump_unique_id_hex(chunk_id)

    unless @retry
      @retry = retry_state(@buffer_config.retry_randomize)

      if @retry.limit?
        handle_limit_reached(error)
      elsif error
        log_retry_error(error, chunk_id_hex, using_secondary)
      end

      return
    end

    # @retry exists

    # Ensure that the current time is greater than or equal to @retry.next_time to avoid the situation when
    # @retry.step is called almost as many times as the number of flush threads in a short time.
    if Time.now >= @retry.next_time
      @retry.step
    else
      @retry.recalc_next_time # to prevent all flush threads from retrying at the same time
    end

    if @retry.limit?
      handle_limit_reached(error)
    elsif error
      log_retry_error(error, chunk_id_hex, using_secondary)
    end
  end
end

#write(chunk) ⇒ Object

Raises:

  • (NotImplementedError) 


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# File 'lib/fluent/plugin/output.rb', line 119

def write(chunk)
  raise NotImplementedError, "BUG: output plugins MUST implement this method"
end

#write_count ⇒ Object 



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# File 'lib/fluent/plugin/output.rb', line 191

def write_count
  @write_count_metrics.get
end

#write_guard(&block) ⇒ Object 



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# File 'lib/fluent/plugin/output.rb', line 930

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: dump_unique_id_hex(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