allow to have a dedicated key for headers content

README.md

@@ -72,6 +72,8 @@ Consume events by single consumer.
       topics <listening topics(separate with comma',')>
       format <input text type (text|json|ltsv|msgpack)> :default => json
       message_key <key (Optional, for text format only, default is message)>
+      add_headers <If true, add kafka's message headers to record>
+      headers_key <key dedicated to store headers content>
       add_prefix <tag prefix (Optional)>
       add_suffix <tag suffix (Optional)>
 
@@ -122,6 +124,7 @@ Consume events by kafka consumer group features..
       message_key <key (Optional, for text format only, default is message)>
       kafka_message_key <key (Optional, If specified, set kafka's message key to this key)>
       add_headers <If true, add kafka's message headers to record>
+      headers_key <key dedicated to store headers content>
       add_prefix <tag prefix (Optional)>
       add_suffix <tag suffix (Optional)>
       retry_emit_limit <Wait retry_emit_limit x 1s when BuffereQueueLimitError happens. The default is nil and it means waiting until BufferQueueLimitError is resolved>
@@ -159,6 +162,7 @@ With the introduction of the rdkafka-ruby based input plugin we hope to support
       message_key <key (Optional, for text format only, default is message)>
       kafka_message_key <key (Optional, If specified, set kafka's message key to this key)>
       add_headers <If true, add kafka's message headers to record>
+      headers_key <key dedicated to store headers content>
       add_prefix <tag prefix (Optional)>
       add_suffix <tag suffix (Optional)>
       retry_emit_limit <Wait retry_emit_limit x 1s when BuffereQueueLimitError happens. The default is nil and it means waiting until BufferQueueLimitError is resolved>

lib/fluent/plugin/in_kafka.rb

@@ -51,6 +51,11 @@ class Fluent::KafkaInput < Fluent::Input
   config_param :kafka_message_key, :string, :default => nil,
                :desc => "Set kafka's message key to this field"
 
+  config_param :add_headers, :bool, :default => false,
+               :desc => "Add kafka's message headers to event record"
+  config_param :headers_key, :string, :default => nil,
+               :desc => "Record key to store kafka's message headers"
+
   # Kafka#fetch_messages options
   config_param :max_bytes, :integer, :default => nil,
                :desc => "Maximum number of bytes to fetch."
@@ -235,6 +240,8 @@ def start
         @record_time_key,
         @tag_source,
         @record_tag_key,
+        @add_headers,
+        @headers_key,
         opt)
     }
     @topic_watchers.each {|tw|
@@ -259,7 +266,7 @@ def run
   end
 
   class TopicWatcher < Coolio::TimerWatcher
-    def initialize(topic_entry, kafka, interval, parser, add_prefix, add_suffix, offset_manager, router, kafka_message_key, time_source, record_time_key, tag_source, record_tag_key, options={})
+    def initialize(topic_entry, kafka, interval, parser, add_prefix, add_suffix, offset_manager, router, kafka_message_key, time_source, record_time_key, tag_source, record_tag_key, add_headers, headers_key, options={})
       @topic_entry = topic_entry
       @kafka = kafka
       @callback = method(:consume)
@@ -274,6 +281,8 @@ def initialize(topic_entry, kafka, interval, parser, add_prefix, add_suffix, off
       @record_time_key = record_time_key
       @tag_source = tag_source
       @record_tag_key = record_tag_key
+      @add_headers = add_headers
+      @headers_key = headers_key
 
       @next_offset = @topic_entry.offset
       if @topic_entry.offset == -1 && offset_manager
@@ -332,6 +341,16 @@ def consume
           if @kafka_message_key
             record[@kafka_message_key] = msg.key
           end
+          if @add_headers
+            if @headers_key
+              headers_record = record[@headers_key] = {}
+            else
+              headers_record = record
+            end
+            msg.headers.each_pair { |k, v|
+              headers_record[k] = v
+            }
+          end
           es.add(record_time, record)
         rescue => e
           $log.warn "parser error in #{@topic_entry.topic}/#{@topic_entry.partition}", :error => e.to_s, :value => msg.value, :offset => msg.offset

lib/fluent/plugin/in_kafka_group.rb

@@ -20,6 +20,8 @@ class Fluent::KafkaGroupInput < Fluent::Input
                :desc => "For 'text' format only."
   config_param :add_headers, :bool, :default => false,
                :desc => "Add kafka's message headers to event record"
+  config_param :headers_key, :string, :default => nil,
+               :desc => "Record key to store kafka's message headers"
   config_param :add_prefix, :string, :default => nil,
                :desc => "Tag prefix (Optional)"
   config_param :add_suffix, :string, :default => nil,
@@ -259,7 +261,7 @@ def reconnect_consumer
   end
 
   def process_batch_with_record_tag(batch)
-    es = {} 
+    es = {}
     batch.messages.each { |msg|
       begin
         record = @parser_proc.call(msg)
@@ -285,8 +287,13 @@ def process_batch_with_record_tag(batch)
           record[@kafka_message_key] = msg.key
         end
         if @add_headers
+          if @headers_key
+            headers_record = record[@headers_key] = {}
+          else
+            headers_record = record
+          end
           msg.headers.each_pair { |k, v|
-            record[k] = v
+            headers_record[k] = v
           }
         end
         es[tag].add(record_time, record)
@@ -332,8 +339,13 @@ def process_batch(batch)
           record[@kafka_message_key] = msg.key
         end
         if @add_headers
+          if @headers_key
+            headers_record = record[@headers_key] = {}
+          else
+            headers_record = record
+          end
           msg.headers.each_pair { |k, v|
-            record[k] = v
+            headers_record[k] = v
           }
         end
         es.add(record_time, record)
@@ -355,7 +367,7 @@ def run
           if @tag_source == :record
             process_batch_with_record_tag(batch)
           else
-            process_batch(batch) 
+            process_batch(batch)
           end
         }
       rescue ForShutdown

lib/fluent/plugin/in_rdkafka_group.rb

@@ -18,6 +18,8 @@ class Fluent::Plugin::RdKafkaGroupInput < Fluent::Plugin::Input
                :desc => "For 'text' format only."
   config_param :add_headers, :bool, :default => false,
                :desc => "Add kafka's message headers to event record"
+  config_param :headers_key, :string, :default => nil,
+               :desc => "Record key to store kafka's message headers"
   config_param :add_prefix, :string, :default => nil,
                :desc => "Tag prefix (Optional)"
   config_param :add_suffix, :string, :default => nil,
@@ -254,8 +256,13 @@ def run
                 record[@kafka_message_key] = msg.key
               end
               if @add_headers
+                if @headers_key
+                  headers_record = record[@headers_key] = {}
+                else
+                  headers_record = record
+                end
                 msg.headers.each_pair { |k, v|
-                  record[k] = v
+                  headers_record[k] = v
                 }
               end
               es.add(record_time, record)

test/plugin/test_in_kafka.rb

@@ -21,7 +21,6 @@ def create_driver(conf = CONFIG)
     Fluent::Test::Driver::Input.new(Fluent::KafkaInput).configure(conf)
   end
 
-
   def test_configure
     d = create_driver
     assert_equal TOPIC_NAME, d.instance.topics
@@ -63,4 +62,63 @@ def test_consume
       assert_equal expected, d.events[0][2]
     end
   end
+
+  class ConsumeWithHeadersTest < self
+    CONFIG_TEMPLATE = %[
+    @type kafka
+    brokers localhost:9092
+    format text
+    @label @kafka
+    topics %<topic>s
+    %<conf_adds>s
+  ].freeze
+
+    def topic_random
+      "kafka-input-#{SecureRandom.uuid}"
+    end
+
+    def kafka_test_context(conf_adds: '', topic: topic_random, conf_template: CONFIG_TEMPLATE)
+      kafka = Kafka.new(['localhost:9092'], client_id: 'kafka')
+      producer = kafka.producer(required_acks: 1)
+
+      config = format(conf_template, topic: topic, conf_adds: conf_adds)
+      driver = create_driver(config)
+
+      yield topic, producer, driver
+    ensure
+      kafka.delete_topic(topic)
+      kafka.close
+    end
+
+    def test_with_headers_content_merged_into_record
+      conf_adds = 'add_headers true'
+      kafka_test_context(conf_adds: conf_adds) do |topic, producer, driver|
+        driver.run(expect_records: 1, timeout: 5) do
+          producer.produce('Hello, fluent-plugin-kafka!', topic: topic, headers: { header1: 'content1' })
+          producer.deliver_messages
+        end
+
+        expected = { 'message' => 'Hello, fluent-plugin-kafka!',
+                     'header1' => 'content1' }
+        assert_equal expected, driver.events[0][2]
+      end
+    end
+
+    def test_with_headers_content_merged_under_dedicated_key
+      conf_adds = %(
+        add_headers true
+        headers_key kafka_headers
+      )
+      kafka_test_context(conf_adds: conf_adds) do |topic, producer, driver|
+        driver.run(expect_records: 1, timeout: 5) do
+          producer.produce('Hello, fluent-plugin-kafka!', topic: topic, headers: { header1: 'content1' })
+          producer.deliver_messages
+        end
+
+        expected = { 'message' => 'Hello, fluent-plugin-kafka!',
+                     'kafka_headers' => { 'header1' => 'content1' } }
+        assert_equal expected, driver.events[0][2]
+      end
+    end
+  end
 end

test/plugin/test_in_kafka_group.rb

@@ -23,7 +23,6 @@ def create_driver(conf = CONFIG)
     Fluent::Test::Driver::Input.new(Fluent::KafkaGroupInput).configure(conf)
   end
 
-
   def test_configure
     d = create_driver
     assert_equal [TOPIC_NAME], d.instance.topics
@@ -48,14 +47,6 @@ def teardown
     end
 
     def test_consume
-      conf = %[
-        @type kafka
-        brokers localhost:9092
-        format text
-        @label @kafka
-        refresh_topic_interval 0
-        topics #{TOPIC_NAME}
-      ]
       d = create_driver
 
       d.run(expect_records: 1, timeout: 10) do
@@ -66,4 +57,65 @@ def test_consume
       assert_equal expected, d.events[0][2]
     end
   end
+
+  class ConsumeWithHeadersTest < self
+    CONFIG_TEMPLATE = %(
+    @type kafka
+    brokers localhost:9092
+    consumer_group fluentd
+    format text
+    refresh_topic_interval 0
+    @label @kafka
+    topics %<topic>s
+    %<conf_adds>s
+  ).freeze
+
+    def topic_random
+      "kafka-input-#{SecureRandom.uuid}"
+    end
+
+    def kafka_test_context(conf_adds: '', topic: topic_random, conf_template: CONFIG_TEMPLATE)
+      kafka = Kafka.new(['localhost:9092'], client_id: 'kafka')
+      producer = kafka.producer(required_acks: 1)
+
+      config = format(conf_template, topic: topic, conf_adds: conf_adds)
+      driver = create_driver(config)
+
+      yield topic, producer, driver
+    ensure
+      kafka.delete_topic(topic)
+      kafka.close
+    end
+
+    def test_with_headers_content_merged_into_record
+      conf_adds = 'add_headers true'
+      kafka_test_context(conf_adds: conf_adds) do |topic, producer, driver|
+        driver.run(expect_records: 1, timeout: 5) do
+          producer.produce('Hello, fluent-plugin-kafka!', topic: topic, headers: { header1: 'content1' })
+          producer.deliver_messages
+        end
+
+        expected = { 'message' => 'Hello, fluent-plugin-kafka!',
+                     'header1' => 'content1' }
+        assert_equal expected, driver.events[0][2]
+      end
+    end
+
+    def test_with_headers_content_merged_under_dedicated_key
+      conf_adds = %(
+        add_headers true
+        headers_key kafka_headers
+      )
+      kafka_test_context(conf_adds: conf_adds) do |topic, producer, driver|
+        driver.run(expect_records: 1, timeout: 5) do
+          producer.produce('Hello, fluent-plugin-kafka!', topic: topic, headers: { header1: 'content1' })
+          producer.deliver_messages
+        end
+
+        expected = { 'message' => 'Hello, fluent-plugin-kafka!',
+                     'kafka_headers' => { 'header1' => 'content1' } }
+        assert_equal expected, driver.events[0][2]
+      end
+    end
+  end
 end