fix bug, constantize TIMEOUT_MS, add README.md info

README.md

@@ -49,9 +49,9 @@ promise.state                          # the state of the promise
 require 'hermann/producer'
 
 p = Hermann::Producer.new('topic', ['localhost:6667'])  # arguments topic, list of brokers
-f = p.push('hello world from mri')                    
-f.state                                               
-p.tick_reactor                                        
+f = p.push('hello world from mri')
+f.state
+p.tick_reactor
 f.state
 ```
 
@@ -94,8 +94,18 @@ the_consumer.consume(new_topic) do |msg|   # can change topic with optional argu
 end
 ```
 
+### Metadata request (MRI-only)
 
+Topic and cluster metadata may be retrieved in the MRI version by querying the Kafka brokers.
 
+```ruby
+require 'hermann'
+require 'hermann/discovery/metadata'
+
+c = Hermann::Discovery::Metadata.new( "localhost:9092" )
+puts c.get_topics.inspect
+puts c.get_topics("only_this_topic").inspect
+```
 
 
 

ext/hermann/hermann_lib.c

@@ -778,7 +778,7 @@ static VALUE producer_metadata_make_hash(struct rd_kafka_metadata *data)
 
 		for ( j = 0 ; j < data->topics[i].partition_cnt ; j++ ) {
 			VALUE partition_hash = rb_hash_new();
-			rd_kafka_metadata_partition_t *partition = &(data->topics[i].partitions[i]);
+			rd_kafka_metadata_partition_t *partition = &(data->topics[i].partitions[j]);
 
 			/* id => 1, leader_id => 0 */
 			rb_hash_aset(partition_hash, ID2SYM(rb_intern("id")), INT2FIX(partition->id));

lib/hermann/discovery/metadata.rb

@@ -3,13 +3,14 @@ require 'hermann_lib'
 module Hermann
   module Discovery
     class Metadata
+      TIMEOUT_MS = 200
       def initialize(brokers)
         raise "this is an MRI api only!" if Hermann.jruby?
         @internal = Hermann::Lib::Producer.new(brokers)
       end
 
-      def get_topics
-        @internal.metadata(nil, 200)
+      def get_topics(filter_topics = nil)
+        @internal.metadata(filter_topics, TIMEOUT_MS)
       end
     end
   end

scripts/metadata_mri.rb

@@ -3,5 +3,5 @@ require 'hermann'
 require 'hermann/discovery/metadata'
 
 c = Hermann::Discovery::Metadata.new( "localhost:9092" )
-puts c.get_topics.inspect
+puts c.get_topics("maxwell").inspect