66 lines
1.5 KiB
Go
66 lines
1.5 KiB
Go
package events
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import (
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"context"
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"time"
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"github.com/containerd/typeurl"
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"github.com/gogo/protobuf/types"
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)
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// Envelope provides the packaging for an event.
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type Envelope struct {
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Timestamp time.Time
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Namespace string
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Topic string
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Event *types.Any
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}
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// Field returns the value for the given fieldpath as a string, if defined.
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// If the value is not defined, the second value will be false.
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func (e *Envelope) Field(fieldpath []string) (string, bool) {
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if len(fieldpath) == 0 {
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return "", false
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}
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switch fieldpath[0] {
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// unhandled: timestamp
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case "namespace":
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return string(e.Namespace), len(e.Namespace) > 0
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case "topic":
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return string(e.Topic), len(e.Topic) > 0
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case "event":
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decoded, err := typeurl.UnmarshalAny(e.Event)
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if err != nil {
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return "", false
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}
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adaptor, ok := decoded.(interface {
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Field([]string) (string, bool)
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})
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if !ok {
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return "", false
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}
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return adaptor.Field(fieldpath[1:])
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}
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return "", false
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}
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// Event is a generic interface for any type of event
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type Event interface{}
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// Publisher posts the event.
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type Publisher interface {
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Publish(ctx context.Context, topic string, event Event) error
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}
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// Forwarder forwards an event to the underlying event bus
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type Forwarder interface {
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Forward(ctx context.Context, envelope *Envelope) error
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}
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// Subscriber allows callers to subscribe to events
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type Subscriber interface {
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Subscribe(ctx context.Context, filters ...string) (ch <-chan *Envelope, errs <-chan error)
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}
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