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