Update configs rather than recreating topics

.gitignore

@@ -0,0 +1,2 @@
+!/examples/main.tf
+/examples/*

kafka/provider.go

@@ -3,7 +3,7 @@ package kafka
 import (
 	"fmt"
 
-	samara "github.com/Shopify/sarama"
+	sarama "github.com/Shopify/sarama"
 	"github.com/hashicorp/terraform/helper/schema"
 	"github.com/hashicorp/terraform/terraform"
 )
@@ -57,15 +57,15 @@ func providerConfigure(d *schema.ResourceData) (interface{}, error) {
 
 // Client is ok
 type Client struct {
-	client samara.Client
+	client sarama.Client
 	config *Config
 }
 
 // NewClient is
 func NewClient(config *Config) (*Client, error) {
-	kafkaConfig := samara.NewConfig()
-	kafkaConfig.Version = samara.V0_11_0_0
-	c, err := samara.NewClient(config.Brokers, kafkaConfig)
+	kafkaConfig := sarama.NewConfig()
+	kafkaConfig.Version = sarama.V0_11_0_0
+	c, err := sarama.NewClient(config.Brokers, kafkaConfig)
 
 	if err != nil {
 		fmt.Println("Error connecting to kafka")

kafka/resource_kafka_topic.go

@@ -6,15 +6,16 @@ import (
 	"log"
 	"time"
 
-	samara "github.com/Shopify/sarama"
+	sarama "github.com/Shopify/sarama"
 	"github.com/hashicorp/terraform/helper/schema"
 )
 
 func kafkaTopicResource() *schema.Resource {
 	return &schema.Resource{
 		Create: topicCreate,
-		Delete: topicDelete,
 		Read:   topicRead,
+		Update: topicUpdate,
+		Delete: topicDelete,
 		Importer: &schema.ResourceImporter{
 			State: schema.ImportStatePassthrough,
 		},
@@ -40,7 +41,7 @@ func kafkaTopicResource() *schema.Resource {
 			"config": {
 				Type:        schema.TypeMap,
 				Optional:    true,
-				ForceNew:    true,
+				ForceNew:    false,
 				Description: "the config",
 			},
 		},
@@ -56,8 +57,8 @@ func topicCreate(d *schema.ResourceData, meta interface{}) error {
 		return err
 	}
 
-	req := &samara.CreateTopicsRequest{
-		TopicDetails: map[string]*samara.TopicDetail{
+	req := &sarama.CreateTopicsRequest{
+		TopicDetails: map[string]*sarama.TopicDetail{
 			t.Name: {
 				NumPartitions:     t.Partitions,
 				ReplicationFactor: t.ReplicationFactor,
@@ -70,7 +71,7 @@ func topicCreate(d *schema.ResourceData, meta interface{}) error {
 
 	if err == nil {
 		for _, e := range res.TopicErrors {
-			if e.Err != samara.ErrNoError {
+			if e.Err != sarama.ErrNoError {
 				return fmt.Errorf("%s", e.Err)
 			}
 		}
@@ -81,7 +82,29 @@ func topicCreate(d *schema.ResourceData, meta interface{}) error {
 }
 
 func topicUpdate(d *schema.ResourceData, meta interface{}) error {
-	return errors.New("Updates NYI")
+	c := meta.(*Client)
+	t := metaToTopicConfig(d, meta)
+	broker, err := AvailableBrokerFromList(c.config.Brokers)
+
+	if err != nil {
+		return err
+	}
+
+	r := &sarama.AlterConfigsRequest{
+		Resources:    configToResources(t.Name, t.Config),
+		ValidateOnly: false,
+	}
+	res, err := broker.AlterConfigs(r)
+
+	if err == nil {
+		for _, e := range res.Resources {
+			if e.ErrorCode != int16(sarama.ErrNoError) {
+				return errors.New(e.ErrorMsg)
+			}
+		}
+	}
+
+	return nil
 }
 
 func topicDelete(d *schema.ResourceData, meta interface{}) error {
@@ -94,15 +117,15 @@ func topicDelete(d *schema.ResourceData, meta interface{}) error {
 		return err
 	}
 
-	req := &samara.DeleteTopicsRequest{
+	req := &sarama.DeleteTopicsRequest{
 		Topics:  []string{t.Name},
 		Timeout: 1000 * time.Millisecond,
 	}
 	res, err := broker.DeleteTopics(req)
 
 	if err == nil {
 		for k, e := range res.TopicErrorCodes {
-			if e != samara.ErrNoError {
+			if e != sarama.ErrNoError {
 				return fmt.Errorf("%s : %s", k, e)
 			}
 		}

kafka/utils.go

@@ -5,14 +5,14 @@ import (
 	"fmt"
 	"log"
 
-	samara "github.com/Shopify/sarama"
+	sarama "github.com/Shopify/sarama"
 	"github.com/hashicorp/terraform/helper/schema"
 )
 
 // ReplicaCount returns the replication_factor for a partition
 // Returns an error if it cannot determine the count, or if the number of
 // replicas is different accross partitions
-func ReplicaCount(c samara.Client, topic string, partitions []int32) (int, error) {
+func ReplicaCount(c sarama.Client, topic string, partitions []int32) (int, error) {
 	count := -1
 
 	for _, p := range partitions {
@@ -33,13 +33,13 @@ func ReplicaCount(c samara.Client, topic string, partitions []int32) (int, error
 
 // AvailableBrokerFromList finds a broker that we can talk to
 // Returns the last know error
-func AvailableBrokerFromList(brokers []string) (*samara.Broker, error) {
+func AvailableBrokerFromList(brokers []string) (*sarama.Broker, error) {
 	var err error
-	kafkaConfig := samara.NewConfig()
-	kafkaConfig.Version = samara.V0_11_0_0
+	kafkaConfig := sarama.NewConfig()
+	kafkaConfig.Version = sarama.V0_11_0_0
 	fmt.Printf("Looking at %v", brokers)
 	for _, b := range brokers {
-		broker := samara.NewBroker(b)
+		broker := sarama.NewBroker(b)
 		err = broker.Open(kafkaConfig)
 		if err == nil {
 			return broker, nil
@@ -59,10 +59,10 @@ type topicConfig struct {
 
 func ConfigForTopic(topic string, brokers []string) (map[string]string, error) {
 	confToSave := map[string]string{}
-	request := &samara.DescribeConfigsRequest{
-		Resources: []*samara.Resource{
-			&samara.Resource{
-				T:           samara.TopicResource,
+	request := &sarama.DescribeConfigsRequest{
+		Resources: []*sarama.Resource{
+			&sarama.Resource{
+				T:           sarama.TopicResource,
 				Name:        topic,
 				ConfigNames: []string{"segment.ms"},
 			},
@@ -90,6 +90,7 @@ func ConfigForTopic(topic string, brokers []string) (map[string]string, error) {
 	}
 	return confToSave, nil
 }
+
 func metaToTopicConfig(d *schema.ResourceData, meta interface{}) topicConfig {
 	topicName := d.Get("name").(string)
 	partitions := d.Get("partitions").(int)
@@ -113,3 +114,24 @@ func metaToTopicConfig(d *schema.ResourceData, meta interface{}) topicConfig {
 		Config:            m2,
 	}
 }
+
+func configToResources(topic string, config map[string]*string) []*sarama.AlterConfigsResource {
+	res := make([]*sarama.AlterConfigsResource, len(config))
+	i := 0
+
+	for k, v := range config {
+		res[i] = &sarama.AlterConfigsResource{
+			T:    sarama.TopicResource,
+			Name: topic,
+			ConfigEntries: []*sarama.ConfigEntryKV{
+				&sarama.ConfigEntryKV{
+					Name:  k,
+					Value: *v,
+				},
+			},
+		}
+		i++
+	}
+
+	return res
+}