Class: Fluent::TraceAccumulator

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

Overview

Buffers and groups log records if they contain exception stack traces.

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(message_field, languages, **options, &emit_callback) ⇒ TraceAccumulator

If message_field is nil, the instance is set up to accumulate records that are plain strings (i.e. the whole record is concatenated). Otherwise, the instance accepts records that are dictionaries (usually originating from structured JSON logs) and accumulates just the content of the given message field. message_field may contain the empty string. In this case, the TraceAccumulator ‘learns’ the field name from the first record by checking for some pre-defined common field names of text logs. The option parameter can be used to pass the following parameters: force_line_breaks adds line breaks when combining exception stacks max_lines and max_bytes limit the maximum amount of data to be buffered. The default value 0 indicates ‘no limit’.



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# File 'lib/fluent/plugin/exception_detector.rb', line 315

def initialize(message_field, languages, **options, &emit_callback)
  @exception_detector = Fluent::ExceptionDetector.new(*languages)
  @message_field = message_field
  @force_line_breaks = options[:force_line_breaks] || false
  @max_lines = options[:max_lines]           || 0
  @max_bytes = options[:max_bytes]           || 0
  @emit = emit_callback
  @messages = []
  @buffer_start_time = Time.now
  @buffer_size = 0
  @first_record = nil
  @first_timestamp = nil
end

Instance Attribute Details

#buffer_start_time ⇒ Object (readonly)

Returns the value of attribute buffer_start_time.



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# File 'lib/fluent/plugin/exception_detector.rb', line 301

def buffer_start_time
  @buffer_start_time
end

Instance Method Details

#flush ⇒ Object 



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# File 'lib/fluent/plugin/exception_detector.rb', line 345

def flush
  case @messages.length
  when 0
    return
  when 1
    @emit.call(@first_timestamp, @first_record)
  else
    combined_message = @messages.join
    if @message_field.nil?
      output_record = combined_message
    else
      output_record = @first_record
      output_record[@message_field] = combined_message
    end
    @emit.call(@first_timestamp, output_record)
  end
  @messages = []
  @first_record = nil
  @first_timestamp = nil
  @buffer_size = 0
end

#force_flush ⇒ Object 



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# File 'lib/fluent/plugin/exception_detector.rb', line 367

def force_flush
  flush
  @exception_detector.reset
end

#push(time_sec, record) ⇒ Object 



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# File 'lib/fluent/plugin/exception_detector.rb', line 329

def push(time_sec, record)
  message = extract_message(record)
  if message.nil?
    @exception_detector.reset
    detection_status = :no_trace
  else
    force_flush if @max_bytes > 0 &&
                   @buffer_size + message.length > @max_bytes
    detection_status = @exception_detector.update(message)
  end

  update_buffer(detection_status, time_sec, record, message)

  force_flush if @max_lines > 0 && @messages.length == @max_lines
end