reduce client close bookkeeping

async_producer.go

@@ -92,9 +92,8 @@ func newTransactionManager(conf *Config, client Client) (*transactionManager, er
 }
 
 type asyncProducer struct {
-	client    Client
-	conf      *Config
-	ownClient bool
+	client Client
+	conf   *Config
 
 	errors                    chan *ProducerError
 	input, successes, retries chan *ProducerMessage
@@ -113,18 +112,19 @@ func NewAsyncProducer(addrs []string, conf *Config) (AsyncProducer, error) {
 	if err != nil {
 		return nil, err
 	}
-
-	p, err := NewAsyncProducerFromClient(client)
-	if err != nil {
-		return nil, err
-	}
-	p.(*asyncProducer).ownClient = true
-	return p, nil
+	return newAsyncProducer(client)
 }
 
 // NewAsyncProducerFromClient creates a new Producer using the given client. It is still
 // necessary to call Close() on the underlying client when shutting down this producer.
 func NewAsyncProducerFromClient(client Client) (AsyncProducer, error) {
+	// For clients passed in by the client, ensure we don't
+	// call Close() on it.
+	cli := &nopCloserClient{client}
+	return newAsyncProducer(cli)
+}
+
+func newAsyncProducer(client Client) (AsyncProducer, error) {
 	// Check that we are not dealing with a closed Client before processing any other arguments
 	if client.Closed() {
 		return nil, ErrClosedClient
@@ -999,11 +999,9 @@ func (p *asyncProducer) shutdown() {
 
 	p.inFlight.Wait()
 
-	if p.ownClient {
-		err := p.client.Close()
-		if err != nil {
-			Logger.Println("producer/shutdown failed to close the embedded client:", err)
-		}
+	err := p.client.Close()
+	if err != nil {
+		Logger.Println("producer/shutdown failed to close the embedded client:", err)
 	}
 
 	close(p.input)

client.go

@@ -911,3 +911,18 @@ func (client *client) getConsumerMetadata(consumerGroup string, attemptsRemainin
 	client.resurrectDeadBrokers()
 	return retry(ErrOutOfBrokers)
 }
+
+// nopCloserClient embeds an existing Client, but disables
+// the Close method (yet all other methods pass
+// through unchanged). This is for use in larger structs
+// where it is undesirable to close the client that was
+// passed in by the caller.
+type nopCloserClient struct {
+	Client
+}
+
+// Close intercepts and purposely does not call the underlying
+// client's Close() method.
+func (ncc *nopCloserClient) Close() error {
+	return nil
+}

consumer.go

@@ -75,9 +75,8 @@ type Consumer interface {
 }
 
 type consumer struct {
-	client    Client
-	conf      *Config
-	ownClient bool
+	client Client
+	conf   *Config
 
 	lock            sync.Mutex
 	children        map[string]map[int32]*partitionConsumer
@@ -90,18 +89,19 @@ func NewConsumer(addrs []string, config *Config) (Consumer, error) {
 	if err != nil {
 		return nil, err
 	}
-
-	c, err := NewConsumerFromClient(client)
-	if err != nil {
-		return nil, err
-	}
-	c.(*consumer).ownClient = true
-	return c, nil
+	return newConsumer(client)
 }
 
 // NewConsumerFromClient creates a new consumer using the given client. It is still
 // necessary to call Close() on the underlying client when shutting down this consumer.
 func NewConsumerFromClient(client Client) (Consumer, error) {
+	// For clients passed in by the client, ensure we don't
+	// call Close() on it.
+	cli := &nopCloserClient{client}
+	return newConsumer(cli)
+}
+
+func newConsumer(client Client) (Consumer, error) {
 	// Check that we are not dealing with a closed Client before processing any other arguments
 	if client.Closed() {
 		return nil, ErrClosedClient
@@ -118,10 +118,7 @@ func NewConsumerFromClient(client Client) (Consumer, error) {
 }
 
 func (c *consumer) Close() error {
-	if c.ownClient {
-		return c.client.Close()
-	}
-	return nil
+	return c.client.Close()
 }
 
 func (c *consumer) Topics() ([]string, error) {

consumer_group.go

@@ -52,8 +52,7 @@ type ConsumerGroup interface {
 }
 
 type consumerGroup struct {
-	client    Client
-	ownClient bool
+	client Client
 
 	config   *Config
 	consumer Consumer
@@ -73,20 +72,24 @@ func NewConsumerGroup(addrs []string, groupID string, config *Config) (ConsumerG
 		return nil, err
 	}
 
-	c, err := NewConsumerGroupFromClient(groupID, client)
+	c, err := newConsumerGroup(groupID, client)
 	if err != nil {
 		_ = client.Close()
-		return nil, err
 	}
-
-	c.(*consumerGroup).ownClient = true
-	return c, nil
+	return c, err
 }
 
 // NewConsumerGroupFromClient creates a new consumer group using the given client. It is still
 // necessary to call Close() on the underlying client when shutting down this consumer.
 // PLEASE NOTE: consumer groups can only re-use but not share clients.
 func NewConsumerGroupFromClient(groupID string, client Client) (ConsumerGroup, error) {
+	// For clients passed in by the client, ensure we don't
+	// call Close() on it.
+	cli := &nopCloserClient{client}
+	return newConsumerGroup(groupID, cli)
+}
+
+func newConsumerGroup(groupID string, client Client) (ConsumerGroup, error) {
 	config := client.Config()
 	if !config.Version.IsAtLeast(V0_10_2_0) {
 		return nil, ConfigurationError("consumer groups require Version to be >= V0_10_2_0")
@@ -131,10 +134,8 @@ func (c *consumerGroup) Close() (err error) {
 			err = e
 		}
 
-		if c.ownClient {
-			if e := c.client.Close(); e != nil {
-				err = e
-			}
+		if e := c.client.Close(); e != nil {
+			err = e
 		}
 	})
 	return