blob: d2a9fa2808cea568297f5f9cbeacb8e2e0485213 [file] [log] [blame]
// Copyright 2016 The Vanadium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package discovery
import "v.io/v23/context"
// Update is the interface for a discovery update.
type Update interface {
// IsLost returns true when this update corresponds to an advertisement
// that led to a previous update vanishing.
IsLost() bool
// Id returns the universal unique identifier of the advertisement.
Id() AdId
// InterfaceName returns the interface name that the service implements.
InterfaceName() string
// Addresses returns the addresses (vanadium object names) that the service
// is served on.
Addresses() []string
// Attribute returns the named attribute. An empty string is returned if
// not found.
Attribute(name string) string
// Attachment returns the channel on which the named attachment can be read.
// Nil data is returned if not found.
//
// This may do RPC calls if the attachment is not fetched yet and fetching
// will fail if the context is canceled or exceeds its deadline.
//
// Attachments may not be available when this update is for lost advertisement.
Attachment(ctx *context.T, name string) <-chan DataOrError
// Advertisement returns a copy of the advertisement that this update
// corresponds to.
//
// The returned advertisement may not include all attachments.
Advertisement() Advertisement
}
// DataOrError contains either an attachment data or an error
// encountered fetching the attachment.
type DataOrError struct {
Data []byte
Error error
}