[kafka_consumer] adding new configuration elements.

[kafka_consumer] fix cops.

kafka_consumer/ci/kafka_consumer.rake

@@ -32,7 +32,7 @@ namespace :ci do
       Wait.for 9092
       wait_on_docker_logs('resources_kafka_1', 20, ' started (kafka.server.KafkaServer)')
       wait_on_docker_logs('resources_zookeeper_1', 20, 'NoNode for /brokers')
-      if Gem::Version::new(kafka_consumer_version) > Gem::Version::new(kafka_legacy)
+      if Gem::Version.new(kafka_consumer_version) > Gem::Version.new(kafka_legacy)
         wait_on_docker_logs('resources_kafka_1', 20, 'Created topic "marvel"')
         wait_on_docker_logs('resources_kafka_1', 20, 'Created topic "dc"')
       end
@@ -42,7 +42,6 @@ namespace :ci do
            docker-compose -f #{ENV['TRAVIS_BUILD_DIR']}/kafka/ci/resources/docker-compose-single-broker.yml scale kafka=2)
       wait_on_docker_logs('resources_kafka_2', 20, ' started (kafka.server.KafkaServer)')
 
-
     end
 
     task before_script: ['ci:common:before_script'] do

kafka_consumer/conf.yaml.example

@@ -3,6 +3,8 @@ init_config:
   # zk_timeout: 5
   # Customize the Kafka connection timeout here
   # kafka_timeout: 5
+  # Customize max number of retries per failed query to Kafka
+  # kafka_retries: 3
   # Customize the number of seconds that must elapse between running this check.
   # When checking Kafka offsets stored in Zookeeper, a single run of this check
   # must stat zookeeper more than the number of consumers * topic_partitions
@@ -11,19 +13,27 @@ init_config:
   # https://help.datadoghq.com/hc/en-us/articles/203557899-How-do-I-change-the-frequency-of-an-agent-check-
   # min_collection_interval: 600
 
+
 instances:
   # In a production environment, it's often useful to specify multiple
   # Kafka / Zookeper nodes for a single check instance. This way you
   # only generate a single check process, but if one host goes down,
   # KafkaClient / KazooClient will try contacting the next host.
   # Details: https://github.com/DataDog/dd-agent/issues/2943
+  #
+  # If you wish to only collect consumer offsets from kafka, because
+  # you're using the new style consumers, you can comment out all
+  # zk_* configuration elements below.
+  # Please note that unlisted consumer groups are not supported at
+  # the moment when zookeeper consumer offset collection is disabled.
   - kafka_connect_str:
       - localhost:9092
       - another_kafka_broker:9092
     zk_connect_str:
       - localhost:2181
       - another_zookeeper:2181
     # zk_prefix: /0.8
+    # kafka_consumer_offsets: false
     consumer_groups:
       my_consumer:  # consumer group name
         my_topic: [0, 1, 4, 12]  # topic_name: list of partitions