woodpecker/cncd/pubsub/pubsub.go

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// 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
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// of senders, called publishers, to a group of consumers.
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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
}