micro/broker/broker.go
2016-12-06 18:37:35 +00:00

81 lines
1.9 KiB
Go

package broker
// Broker is an interface used for asynchronous messaging.
// Its an abstraction over various message brokers
// {NATS, RabbitMQ, Kafka, ...}
type Broker interface {
Options() Options
Address() string
Connect() error
Disconnect() error
Init(...Option) error
Publish(string, *Message, ...PublishOption) error
Subscribe(string, Handler, ...SubscribeOption) (Subscriber, error)
String() string
}
// 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
}
// Subscriber is a convenience return type for the Subscribe method
type Subscriber interface {
Options() SubscribeOptions
Topic() string
Unsubscribe() error
}
// Codec is used for encoding where the broker doesn't natively support
// headers in the message type. In this case the entire message is
// encoded as the payload
type Codec interface {
Marshal(interface{}) ([]byte, error)
Unmarshal([]byte, interface{}) error
String() string
}
var (
DefaultBroker Broker = newHttpBroker()
)
func NewBroker(opts ...Option) Broker {
return newHttpBroker(opts...)
}
func Init(opts ...Option) error {
return DefaultBroker.Init(opts...)
}
func Connect() error {
return DefaultBroker.Connect()
}
func Disconnect() error {
return DefaultBroker.Disconnect()
}
func Publish(topic string, msg *Message, opts ...PublishOption) error {
return DefaultBroker.Publish(topic, msg, opts...)
}
func Subscribe(topic string, handler Handler, opts ...SubscribeOption) (Subscriber, error) {
return DefaultBroker.Subscribe(topic, handler, opts...)
}
func String() string {
return DefaultBroker.String()
}