Class: Racecar::Runner

Inherits:
Object
  • Object
show all
Defined in:
lib/racecar/runner.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(processor, config:, logger:, instrumenter: NullInstrumenter) ⇒ Runner

Returns a new instance of Runner.



7
8
9
10
 
# File 'lib/racecar/runner.rb', line 7

def initialize(processor, config:, logger:, instrumenter: NullInstrumenter)
  @processor, @config, @logger = processor, config, logger
  @instrumenter = instrumenter
end

Instance Attribute Details

#config ⇒ Object (readonly)

Returns the value of attribute config.



5
6
7
 
# File 'lib/racecar/runner.rb', line 5

def config
  @config
end

#consumer ⇒ Object (readonly)

Returns the value of attribute consumer.



5
6
7
 
# File 'lib/racecar/runner.rb', line 5

def consumer
  @consumer
end

#logger ⇒ Object (readonly)

Returns the value of attribute logger.



5
6
7
 
# File 'lib/racecar/runner.rb', line 5

def logger
  @logger
end

#processor ⇒ Object (readonly)

Returns the value of attribute processor.



5
6
7
 
# File 'lib/racecar/runner.rb', line 5

def processor
  @processor
end

Instance Method Details

#run ⇒ Object 



19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
 
# File 'lib/racecar/runner.rb', line 19

def run
  kafka = Kafka.new(
    client_id: config.client_id,
    seed_brokers: config.brokers,
    logger: logger,
    connect_timeout: config.connect_timeout,
    socket_timeout: config.socket_timeout,
    ssl_ca_cert: config.ssl_ca_cert,
    ssl_ca_cert_file_path: config.ssl_ca_cert_file_path,
    ssl_client_cert: config.ssl_client_cert,
    ssl_client_cert_key: config.ssl_client_cert_key,
    sasl_plain_username: config.sasl_plain_username,
    sasl_plain_password: config.sasl_plain_password,
    sasl_scram_username: config.sasl_scram_username,
    sasl_scram_password: config.sasl_scram_password,
    sasl_scram_mechanism: config.sasl_scram_mechanism,
    sasl_over_ssl: config.sasl_over_ssl,
    ssl_ca_certs_from_system: config.ssl_ca_certs_from_system,
    ssl_verify_hostname: config.ssl_verify_hostname
  )

  @consumer = kafka.consumer(
    group_id: config.group_id,
    offset_commit_interval: config.offset_commit_interval,
    offset_commit_threshold: config.offset_commit_threshold,
    session_timeout: config.session_timeout,
    heartbeat_interval: config.heartbeat_interval,
    offset_retention_time: config.offset_retention_time,
    fetcher_max_queue_size: config.max_fetch_queue_size,
  )

  # Stop the consumer on SIGINT, SIGQUIT or SIGTERM.
  trap("QUIT") { stop }
  trap("INT") { stop }
  trap("TERM") { stop }

  # Print the consumer config to STDERR on USR1.
  trap("USR1") { $stderr.puts config.inspect }

  config.subscriptions.each do |subscription|
    consumer.subscribe(
      subscription.topic,
      start_from_beginning: subscription.start_from_beginning,
      max_bytes_per_partition: subscription.max_bytes_per_partition,
    )
  end

  # Configure the consumer with a producer so it can produce messages.
  producer = kafka.producer(
    compression_codec: config.producer_compression_codec,
  )

  processor.configure(consumer: consumer, producer: producer)

  begin
    if processor.respond_to?(:process)
      consumer.each_message(max_wait_time: config.max_wait_time, max_bytes: config.max_bytes) do |message|
        payload = {
          consumer_class: processor.class.to_s,
          topic: message.topic,
          partition: message.partition,
          offset: message.offset,
        }

        @instrumenter.instrument("process_message.racecar", payload) do
          processor.process(message)
          producer.deliver_messages
        end
      end
    elsif processor.respond_to?(:process_batch)
      consumer.each_batch(max_wait_time: config.max_wait_time, max_bytes: config.max_bytes) do |batch|
        payload = {
          consumer_class: processor.class.to_s,
          topic: batch.topic,
          partition: batch.partition,
          first_offset: batch.first_offset,
          message_count: batch.messages.count,
        }

        @instrumenter.instrument("process_batch.racecar", payload) do
          processor.process_batch(batch)
          producer.deliver_messages
        end
      end
    else
      raise NotImplementedError, "Consumer class must implement process or process_batch method"
    end
  rescue Kafka::ProcessingError => e
    @logger.error "Error processing partition #{e.topic}/#{e.partition} at offset #{e.offset}"

    if config.pause_timeout > 0
      # Pause fetches from the partition. We'll continue processing the other partitions in the topic.
      # The partition is automatically resumed after the specified timeout, and will continue where we
      # left off.
      @logger.warn "Pausing partition #{e.topic}/#{e.partition} for #{config.pause_timeout} seconds"
      consumer.pause(
        e.topic,
        e.partition,
        timeout: config.pause_timeout,
        max_timeout: config.max_pause_timeout,
        exponential_backoff: config.pause_with_exponential_backoff?,
      )
    elsif config.pause_timeout == -1
      # A pause timeout of -1 means indefinite pausing, which in ruby-kafka is done by passing nil as
      # the timeout.
      @logger.warn "Pausing partition #{e.topic}/#{e.partition} indefinitely, or until the process is restarted"
      consumer.pause(e.topic, e.partition, timeout: nil)
    end

    config.error_handler.call(e.cause, {
      topic: e.topic,
      partition: e.partition,
      offset: e.offset,
    })

    # Restart the consumer loop.
    retry
  rescue Kafka::InvalidSessionTimeout
    raise ConfigError, "`session_timeout` is set either too high or too low"
  rescue Kafka::Error => e
    error = "#{e.class}: #{e.message}\n" + e.backtrace.join("\n")
    @logger.error "Consumer thread crashed: #{error}"

    config.error_handler.call(e)

    raise
  else
    @logger.info "Gracefully shutting down"
  end
end

#stop ⇒ Object 



12
13
14
15
16
17
 
# File 'lib/racecar/runner.rb', line 12

def stop
  Thread.new do
    processor.teardown
    consumer.stop unless consumer.nil?
  end.join
end