Class: Fluent::KafkaGroupInput

Inherits:
Input
  • Object
show all
Includes:
Fluent::KafkaPluginUtil::SSLSettings, Fluent::KafkaPluginUtil::SaslSettings
Defined in:
lib/fluent/plugin/in_kafka_group.rb

Defined Under Namespace

Classes: ForShutdown

Constant Summary collapse

BufferError = 
if defined?(Fluent::Plugin::Buffer::BufferOverflowError)
  Fluent::Plugin::Buffer::BufferOverflowError
else
  Fluent::BufferQueueLimitError
end

Instance Method Summary collapse

Methods included from Fluent::KafkaPluginUtil::SaslSettings

included

Methods included from Fluent::KafkaPluginUtil::SSLSettings

included, #read_ssl_file

Constructor Details

#initialize ⇒ KafkaGroupInput

Returns a new instance of KafkaGroupInput.



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# File 'lib/fluent/plugin/in_kafka_group.rb', line 62

def initialize
  super
  require 'kafka'

  @time_parser = nil
end

Instance Method Details

#configure(conf) ⇒ Object 



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# File 'lib/fluent/plugin/in_kafka_group.rb', line 79

def configure(conf)
  super

  $log.info "Will watch for topics #{@topics} at brokers " \
            "#{@brokers} and '#{@consumer_group}' group"

  @topics = _config_to_array(@topics)

  if conf['max_wait_ms']
    log.warn "'max_wait_ms' parameter is deprecated. Use second unit 'max_wait_time' instead"
    @max_wait_time = conf['max_wait_ms'].to_i / 1000
  end

  @parser_proc = setup_parser

  @consumer_opts = {:group_id => @consumer_group}
  @consumer_opts[:session_timeout] = @session_timeout if @session_timeout
  @consumer_opts[:offset_commit_interval] = @offset_commit_interval if @offset_commit_interval
  @consumer_opts[:offset_commit_threshold] = @offset_commit_threshold if @offset_commit_threshold

  @fetch_opts = {}
  @fetch_opts[:max_wait_time] = @max_wait_time if @max_wait_time
  @fetch_opts[:min_bytes] = @min_bytes if @min_bytes

  if @use_record_time and @time_format
    @time_parser = Fluent::TextParser::TimeParser.new(@time_format)
  end
end

#emit_events(tag, es) ⇒ Object 



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# File 'lib/fluent/plugin/in_kafka_group.rb', line 215

def emit_events(tag, es)
  retries = 0
  begin
    router.emit_stream(tag, es)
  rescue BufferError
    raise ForShutdown if @consumer.nil?

    if @retry_emit_limit.nil?
      sleep 1
      retry
    end

    if retries < @retry_emit_limit
      retries += 1
      sleep 1
      retry
    else
      raise RuntimeError, "Exceeds retry_emit_limit"
    end
  end
end

#reconnect_consumer ⇒ Object 



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# File 'lib/fluent/plugin/in_kafka_group.rb', line 157

def reconnect_consumer
  log.warn "Stopping Consumer"
  consumer = @consumer
  @consumer = nil
  consumer.stop
  log.warn "Could not connect to broker. Next retry will be in #{@retry_wait_seconds} seconds"
  sleep @retry_wait_seconds
  @consumer = setup_consumer
  log.warn "Re-starting consumer #{Time.now.to_s}"
rescue =>e
  log.error "unexpected error during re-starting consumer object access", :error => e.to_s
  log.error_backtrace
end

#run ⇒ Object 



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

def run
  while @consumer
    begin
      @consumer.each_batch(@fetch_opts) { |batch|
        es = Fluent::MultiEventStream.new
        tag = batch.topic
        tag = @add_prefix + "." + tag if @add_prefix
        tag = tag + "." + @add_suffix if @add_suffix

        batch.messages.each { |msg|
          begin
            record = @parser_proc.call(msg)
            if @use_record_time
              if @time_format
                record_time = @time_parser.parse(record['time'])
              else
                record_time = record['time']
              end
            else
              record_time = Fluent::Engine.now
            end
            es.add(record_time, record)
          rescue => e
            log.warn "parser error in #{batch.topic}/#{batch.partition}", :error => e.to_s, :value => msg.value, :offset => msg.offset
            log.debug_backtrace
          end
        }

        unless es.empty?
          emit_events(tag, es)
        end
      }
    rescue ForShutdown
    rescue => e
      log.error "unexpected error during consuming events from kafka. Re-fetch events.", :error => e.to_s
      log.error_backtrace
      reconnect_consumer
    end
  end
rescue => e
  log.error "unexpected error during consumer object access", :error => e.to_s
  log.error_backtrace
end

#setup_consumer ⇒ Object 



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# File 'lib/fluent/plugin/in_kafka_group.rb', line 149

def setup_consumer
  consumer = @kafka.consumer(@consumer_opts)
  @topics.each { |topic|
    consumer.subscribe(topic, start_from_beginning: @start_from_beginning, max_bytes_per_partition: @max_bytes)
  }
  consumer
end

#setup_parser ⇒ Object 



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# File 'lib/fluent/plugin/in_kafka_group.rb', line 108

def setup_parser
  case @format
  when 'json'
    require 'yajl'
    Proc.new { |msg| Yajl::Parser.parse(msg.value) }
  when 'ltsv'
    require 'ltsv'
    Proc.new { |msg| LTSV.parse(msg.value, {:symbolize_keys => false}).first }
  when 'msgpack'
    require 'msgpack'
    Proc.new { |msg| MessagePack.unpack(msg.value) }
  when 'text'
    Proc.new { |msg| {@message_key => msg.value} }
  end
end

#shutdown ⇒ Object 



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# File 'lib/fluent/plugin/in_kafka_group.rb', line 136

def shutdown
  # This nil assignment should be guarded by mutex in multithread programming manner.
  # But the situation is very low contention, so we don't use mutex for now.
  # If the problem happens, we will add a guard for consumer.
  consumer = @consumer
  @consumer = nil
  consumer.stop

  @thread.join
  @kafka.close
  super
end

#start ⇒ Object 



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# File 'lib/fluent/plugin/in_kafka_group.rb', line 124

def start
  super
 
  @kafka = Kafka.new(seed_brokers: @brokers,
                     ssl_ca_cert: read_ssl_file(@ssl_ca_cert),
                     ssl_client_cert: read_ssl_file(@ssl_client_cert),
                     ssl_client_cert_key: read_ssl_file(@ssl_client_cert_key),
                     sasl_gssapi_principal: @principal, sasl_gssapi_keytab: @keytab)
  @consumer = setup_consumer
  @thread = Thread.new(&method(:run))
end