Support setting the max bytes to fetch per request

Author: dasch

lib/kafka/client.rb

@@ -369,6 +369,7 @@ def fetch_messages(topic:, partition:, offset: :latest, max_wait_time: 5, min_by
         cluster: @cluster,
         logger: @logger,
         min_bytes: min_bytes,
+        max_bytes: max_bytes,
         max_wait_time: max_wait_time,
       )
 

lib/kafka/fetch_operation.rb

@@ -18,15 +18,16 @@ module Kafka
   #     operation.execute
   #
   class FetchOperation
-    def initialize(cluster:, logger:, min_bytes: 1, max_wait_time: 5)
+    def initialize(cluster:, logger:, min_bytes: 1, max_bytes: 10485760, max_wait_time: 5)
       @cluster = cluster
       @logger = logger
       @min_bytes = min_bytes
+      @max_bytes = max_bytes
       @max_wait_time = max_wait_time
       @topics = {}
     end
 
-    def fetch_from_partition(topic, partition, offset: :latest, max_bytes: 1048576)
+    def fetch_from_partition(topic, partition, offset: :latest, max_bytes: 10485760)
       if offset == :earliest
         offset = -2
       elsif offset == :latest
@@ -66,6 +67,7 @@ def execute
         options = {
           max_wait_time: @max_wait_time * 1000, # Kafka expects ms, not secs
           min_bytes: @min_bytes,
+          max_bytes: @max_bytes,
           topics: topics,
         }
 

lib/kafka/protocol/fetch_request.rb

@@ -19,10 +19,11 @@ class FetchRequest
       # @param max_wait_time [Integer]
       # @param min_bytes [Integer]
       # @param topics [Hash]
-      def initialize(max_wait_time:, min_bytes:, topics:)
+      def initialize(max_wait_time:, min_bytes:, max_bytes:, topics:)
         @replica_id = REPLICA_ID
         @max_wait_time = max_wait_time
         @min_bytes = min_bytes
+        @max_bytes = max_bytes
         @topics = topics
       end
 
@@ -31,7 +32,7 @@ def api_key
       end
 
       def api_version
-        2
+        3
       end
 
       def response_class
@@ -42,6 +43,7 @@ def encode(encoder)
         encoder.write_int32(@replica_id)
         encoder.write_int32(@max_wait_time)
         encoder.write_int32(@min_bytes)
+        encoder.write_int32(@max_bytes)
 
         encoder.write_array(@topics) do |topic, partitions|
           encoder.write_string(topic)

spec/broker_spec.rb

@@ -87,6 +87,7 @@ def send_request(request)
       actual_response = broker.fetch_messages(
         max_wait_time: 0,
         min_bytes: 0,
+        max_bytes: 10 * 1024,
         topics: {}
       )