broker

Documentation

Overview

Package broker is an interface used for asynchronous messaging.

Index

• Variables
• func Connect() error
• func Disconnect() error
• func Init(opts ...Option) error
• func Publish(topic string, msg *Message, opts ...PublishOption) error
• func String() string
• type Broker
  • func NewBroker(opts ...Option) Broker
• type Handler
• type Message
• type Option
  • func Addrs(addrs ...string) Option
  • func Codec(c codec.Codec) Option
  • func Registry(r registry.Registry) Option
  • func Secure(b bool) Option
  • func TLSConfig(t *tls.Config) Option
• type Options
• type Publication
• type PublishOption
• type PublishOptions
• type SubscribeOption
  • func DisableAutoAck() SubscribeOption
  • func Queue(name string) SubscribeOption
• type SubscribeOptions
• type Subscriber
  • func Subscribe(topic string, handler Handler, opts ...SubscribeOption) (Subscriber, error)

Variables

var (
	DefaultSubPath = "/_sub"
)

Functions

func Connect

func Connect() error

func Disconnect

func Disconnect() error

func Init

func Init(opts ...Option) error

func Publish

func Publish(topic string, msg *Message, opts ...PublishOption) error

func String

func String() string

Types

type Broker

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
}

Broker is an interface used for asynchronous messaging. Its an abstraction over various message brokers {NATS, RabbitMQ, Kafka, ...}

var (
	DefaultBroker Broker = newHttpBroker()
)

func NewBroker

func NewBroker(opts ...Option) Broker

type Handler

type Handler func(Publication) error

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 Message

type Message struct {
	Header map[string]string
	Body   []byte
}

type Option

type Option func(*Options)

func Addrs

func Addrs(addrs ...string) Option

Addrs sets the host addresses to be used by the broker

func Codec

func Codec(c codec.Codec) Option

Codec sets the codec used for encoding/decoding used where a broker does not support headers

func Registry

func Registry(r registry.Registry) Option

func Secure

func Secure(b bool) Option

Secure communication with the broker

func TLSConfig

func TLSConfig(t *tls.Config) Option

Specify TLS Config

type Options

type Options struct {
	Addrs     []string
	Secure    bool
	Codec     codec.Codec
	TLSConfig *tls.Config
	// Other options for implementations of the interface
	// can be stored in a context
	Context context.Context
}

type Publication

type Publication interface {
	Topic() string
	Message() *Message
	Ack() error
}

Publication is given to a subscription handler for processing

type PublishOption

type PublishOption func(*PublishOptions)

type PublishOptions

type PublishOptions struct {
	// Other options for implementations of the interface
	// can be stored in a context
	Context context.Context
}

type SubscribeOption

type SubscribeOption func(*SubscribeOptions)

func DisableAutoAck

func DisableAutoAck() SubscribeOption

DisableAutoAck will disable auto acking of messages after they have been handled.

func Queue

func Queue(name string) SubscribeOption

Queue sets the name of the queue to share messages on

type SubscribeOptions

type SubscribeOptions struct {
	// AutoAck defaults to true. When a handler returns
	// with a nil error the message is acked.
	AutoAck bool
	// Subscribers with the same queue name
	// will create a shared subscription where each
	// receives a subset of messages.
	Queue string

	// Other options for implementations of the interface
	// can be stored in a context
	Context context.Context
}

type Subscriber

type Subscriber interface {
	Options() SubscribeOptions
	Topic() string
	Unsubscribe() error
}

Subscriber is a convenience return type for the Subscribe method

func Subscribe

func Subscribe(topic string, handler Handler, opts ...SubscribeOption) (Subscriber, error)