72 lines
2 KiB
Go
72 lines
2 KiB
Go
|
// Package pubsub implements a publish-subscriber messaging system.
|
||
|
|
package pubsub
|
||
|
|
|
||
|
|
import (
|
||
|
|
"context"
|
||
|
|
"errors"
|
||
|
|
)
|
||
|
|
|
||
|
|
// ErrNotFound is returned when the named topic does not exist.
|
||
|
|
var ErrNotFound = errors.New("topic not found")
|
||
|
|
|
||
|
|
// Message defines a published message.
|
||
|
|
type Message struct {
|
||
|
|
// ID identifies this message.
|
||
|
|
ID string `json:"id,omitempty"`
|
||
|
|
|
||
|
|
// Data is the actual data in the entry.
|
||
|
|
Data []byte `json:"data"`
|
||
|
|
|
||
|
|
// Labels represents the key-value pairs the entry is lebeled with.
|
||
|
|
Labels map[string]string `json:"labels,omitempty"`
|
||
|
|
}
|
||
|
|
|
||
|
|
// Receiver receives published messages.
|
||
|
|
type Receiver func(Message)
|
||
|
|
|
||
|
|
// Publisher defines a mechanism for communicating messages from a group
|
||
|
|
// of senders, called producers, to a group of consumers.
|
||
|
|
type Publisher interface {
|
||
|
|
// Create creates the named topic.
|
||
|
|
Create(c context.Context, topic string) error
|
||
|
|
|
||
|
|
// Publish publishes the message.
|
||
|
|
Publish(c context.Context, topic string, message Message) error
|
||
|
|
|
||
|
|
// Subscribe subscribes to the topic. The Receiver function is a callback
|
||
|
|
// function that receives published messages.
|
||
|
|
Subscribe(c context.Context, topic string, receiver Receiver) error
|
||
|
|
|
||
|
|
// Remove removes the named topic.
|
||
|
|
Remove(c context.Context, topic string) error
|
||
|
|
}
|
||
|
|
|
||
|
|
// // global instance of the queue.
|
||
|
|
// var global = New()
|
||
|
|
//
|
||
|
|
// // Set sets the global queue.
|
||
|
|
// func Set(p Publisher) {
|
||
|
|
// global = p
|
||
|
|
// }
|
||
|
|
//
|
||
|
|
// // Create creates the named topic.
|
||
|
|
// func Create(c context.Context, topic string) error {
|
||
|
|
// return global.Create(c, topic)
|
||
|
|
// }
|
||
|
|
//
|
||
|
|
// // Publish publishes the message.
|
||
|
|
// func Publish(c context.Context, topic string, message Message) error {
|
||
|
|
// return global.Publish(c, topic, message)
|
||
|
|
// }
|
||
|
|
//
|
||
|
|
// // Subscribe subscribes to the topic. The Receiver function is a callback
|
||
|
|
// // function that receives published messages.
|
||
|
|
// func Subscribe(c context.Context, topic string, receiver Receiver) error {
|
||
|
|
// return global.Subscribe(c, topic, receiver)
|
||
|
|
// }
|
||
|
|
//
|
||
|
|
// // Remove removes the topic.
|
||
|
|
// func Remove(c context.Context, topic string) error {
|
||
|
|
// return global.Remove(c, topic)
|
||
|
|
// }
|