log consumer opens, closes, and exceptions

lib/logstash/inputs/kafka.rb

@@ -221,8 +221,12 @@ def register
 
   public
   def run(logstash_queue)
-    @runner_consumers = consumer_threads.times.map { |i| create_consumer("#{client_id}-#{i}") }
-    @runner_threads = @runner_consumers.map { |consumer| thread_runner(logstash_queue, consumer) }
+    @runner_consumers = consumer_threads.times.map do |index|
+      create_consumer("#{client_id}-#{index}")
+    end
+    @runner_threads = @runner_consumers.map.with_index do |consumer, index|
+      thread_runner(logstash_queue, consumer, index)
+    end
     @runner_threads.each { |t| t.join }
   end # def run
 
@@ -237,9 +241,11 @@ def kafka_consumers
   end
 
   private
-  def thread_runner(logstash_queue, consumer)
+  def thread_runner(logstash_queue, consumer, consumer_index)
+    consumer_identifier = "#{client_id}-#{consumer_index}"
     Thread.new do
       begin
+        logger.info("opening consumer #{consumer_identifier}")
         unless @topics_pattern.nil?
           nooplistener = org.apache.kafka.clients.consumer.internals.NoOpConsumerRebalanceListener.new
           pattern = java.util.regex.Pattern.compile(@topics_pattern)
@@ -270,8 +276,15 @@ def thread_runner(logstash_queue, consumer)
           end
         end
       rescue org.apache.kafka.common.errors.WakeupException => e
-        raise e if !stop?
+        unless stop?
+          logger.error("wakeup exception in consumer #{consumer_identifier}: #{e}")
+          raise e
+        end
+      rescue => e
+        logger.error("uncaught exception in consumer #{consumer_identifier}: #{e}")
+        raise e
       ensure
+        logger.info("closing consumer #{consumer_identifier}")
         consumer.close
       end
     end