[FAB-1165] Use configured PartitionID

Subtask of FAB-890

When publishing to Kafka we have been relying on the
topic only containing one partition (num.partitions = 1),
and the default PartitionID (0) in the config lining
up for a valid combination. This commit configures our
producer PartitionID configured.

Change-Id: Ibba476425a15aff9ff447afdfacbf4b77a41ce0c
Signed-off-by: Luis Sanchez <sanchezl@us.ibm.com>

orderer/kafka/util.go

@@ -30,6 +30,7 @@ const (
 func newBrokerConfig(conf *config.TopLevel) *sarama.Config {
 	brokerConfig := sarama.NewConfig()
 	brokerConfig.Version = conf.Kafka.Version
+	brokerConfig.Producer.Partitioner = newStaticPartitioner(conf.Kafka.PartitionID)
 	return brokerConfig
 }
 
@@ -50,3 +51,23 @@ func newOffsetReq(conf *config.TopLevel, seek int64) *sarama.OffsetRequest {
 	req.AddBlock(conf.Kafka.Topic, conf.Kafka.PartitionID, seek, 1)
 	return req
 }
+
+// newStaticPartitioner returns a PartitionerConstructor that returns a Partitioner
+// that always chooses the specified partition.
+func newStaticPartitioner(partition int32) sarama.PartitionerConstructor {
+	return func(topic string) sarama.Partitioner {
+		return &staticPartitioner{partition}
+	}
+}
+
+type staticPartitioner struct {
+	partitionID int32
+}
+
+func (p *staticPartitioner) Partition(message *sarama.ProducerMessage, numPartitions int32) (int32, error) {
+	return p.partitionID, nil
+}
+
+func (p *staticPartitioner) RequiresConsistency() bool {
+	return true
+}

orderer/kafka/util_test.go

@@ -0,0 +1,84 @@
+/*
+Copyright IBM Corp. 2016 All Rights Reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+                 http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package kafka
+
+import (
+	"testing"
+
+	"github.com/Shopify/sarama"
+)
+
+func TestStaticPartitioner(t *testing.T) {
+
+	var partition int32 = 3
+	var numberOfPartitions int32 = 6
+
+	partitionerConstructor := newStaticPartitioner(partition)
+	partitioner := partitionerConstructor(testConf.Kafka.Topic)
+
+	for i := 0; i < 10; i++ {
+		assignedPartition, err := partitioner.Partition(new(sarama.ProducerMessage), numberOfPartitions)
+		if err != nil {
+			t.Fatal(err)
+		}
+		if assignedPartition != partition {
+			t.Fatalf("Expected: %v. Actual: %v", partition, assignedPartition)
+		}
+	}
+}
+
+func TestNewBrokerConfig(t *testing.T) {
+
+	topic := testConf.Kafka.Topic
+
+	// use a partition id that is not the 'default' 0
+	var partition int32 = 2
+	originalPartitionID := testConf.Kafka.PartitionID
+	defer func() {
+		testConf.Kafka.PartitionID = originalPartitionID
+	}()
+	testConf.Kafka.PartitionID = partition
+
+	// setup a mock broker that reports that it has 3 partitions for the topic
+	broker := sarama.NewMockBroker(t, 1000)
+	broker.SetHandlerByMap(map[string]sarama.MockResponse{
+		"MetadataRequest": sarama.NewMockMetadataResponse(t).
+			SetBroker(broker.Addr(), broker.BrokerID()).
+			SetLeader(topic, 0, broker.BrokerID()).
+			SetLeader(topic, 1, broker.BrokerID()).
+			SetLeader(topic, 2, broker.BrokerID()),
+		"ProduceRequest": sarama.NewMockProduceResponse(t),
+	})
+
+	config := newBrokerConfig(testConf)
+	producer, err := sarama.NewSyncProducer([]string{broker.Addr()}, config)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	for i := 0; i < 10; i++ {
+		assignedPartition, _, err := producer.SendMessage(&sarama.ProducerMessage{Topic: topic})
+		if err != nil {
+			t.Fatal(err)
+		}
+		if assignedPartition != partition {
+			t.Fatalf("Expected: %v. Actual: %v", partition, assignedPartition)
+		}
+	}
+	producer.Close()
+	broker.Close()
+}