71 lines
1.8 KiB
Go
71 lines
1.8 KiB
Go
// Package events is for event streaming and storage
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package events
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import (
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"encoding/json"
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"errors"
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"time"
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)
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var (
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// ErrMissingTopic is returned if a blank topic was provided to publish
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ErrMissingTopic = errors.New("Missing topic")
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// ErrEncodingMessage is returned from publish if there was an error encoding the message option
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ErrEncodingMessage = errors.New("Error encoding message")
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)
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// Stream is an event streaming interface
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type Stream interface {
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Publish(topic string, msg interface{}, opts ...PublishOption) error
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Subscribe(topic string, opts ...SubscribeOption) (<-chan Event, error)
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}
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// Store is an event store interface
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type Store interface {
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Read(topic string, opts ...ReadOption) ([]*Event, error)
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Write(event *Event, opts ...WriteOption) error
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}
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type AckFunc func() error
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type NackFunc func() error
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// Event is the object returned by the broker when you subscribe to a topic
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type Event struct {
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// ID to uniquely identify the event
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ID string
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// Topic of event, e.g. "registry.service.created"
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Topic string
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// Timestamp of the event
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Timestamp time.Time
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// Metadata contains the values the event was indexed by
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Metadata map[string]string
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// Payload contains the encoded message
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Payload []byte
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ackFunc AckFunc
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nackFunc NackFunc
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}
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// Unmarshal the events message into an object
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func (e *Event) Unmarshal(v interface{}) error {
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return json.Unmarshal(e.Payload, v)
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}
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// Ack acknowledges successful processing of the event in ManualAck mode
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func (e *Event) Ack() error {
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return e.ackFunc()
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}
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func (e *Event) SetAckFunc(f AckFunc) {
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e.ackFunc = f
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}
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// Nack negatively acknowledges processing of the event (i.e. failure) in ManualAck mode
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func (e *Event) Nack() error {
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return e.nackFunc()
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}
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func (e *Event) SetNackFunc(f NackFunc) {
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e.nackFunc = f
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}
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