Update the broker interface

broker/broker.go

@@ -4,28 +4,35 @@ type Broker interface {
 	Address() string
 	Connect() error
 	Disconnect() error
-	Init() error
-	Publish(string, *Message) error
-	Subscribe(string, Handler) (Subscriber, error)
+	Init(...Option) error
+	Publish(string, *Message, ...PublishOption) error
+	Subscribe(string, Handler, ...SubscribeOption) (Subscriber, error)
 	String() string
 }
 
-type Handler func(*Message)
+// Handler is used to process messages via a subscription of a topic.
+// The handler is passed a publication interface which contains the
+// message and optional Ack method to acknowledge receipt of the message.
+type Handler func(Publication) error
 
 type Message struct {
 	Header map[string]string
 	Body   []byte
 }
 
+// Publication is given to a subscription handler for processing
+type Publication interface {
+	Topic() string
+	Message() *Message
+	Ack() error
+}
+
 type Subscriber interface {
+	Config() SubscribeOptions
 	Topic() string
 	Unsubscribe() error
 }
 
-type options struct{}
-
-type Option func(*options)
-
 var (
 	DefaultBroker Broker = newHttpBroker([]string{})
 )
@@ -34,8 +41,8 @@ func NewBroker(addrs []string, opt ...Option) Broker {
 	return newHttpBroker(addrs, opt...)
 }
 
-func Init() error {
-	return DefaultBroker.Init()
+func Init(opts ...Option) error {
+	return DefaultBroker.Init(opts...)
 }
 
 func Connect() error {
@@ -46,12 +53,12 @@ func Disconnect() error {
 	return DefaultBroker.Disconnect()
 }
 
-func Publish(topic string, msg *Message) error {
-	return DefaultBroker.Publish(topic, msg)
+func Publish(topic string, msg *Message, opts ...PublishOption) error {
+	return DefaultBroker.Publish(topic, msg, opts...)
 }
 
-func Subscribe(topic string, handler Handler) (Subscriber, error) {
-	return DefaultBroker.Subscribe(topic, handler)
+func Subscribe(topic string, handler Handler, opts ...SubscribeOption) (Subscriber, error) {
+	return DefaultBroker.Subscribe(topic, handler, opts...)
 }
 
 func String() string {