4ceceda757
This commit adds a peer notifier package which provides clients with a subscription to peer online and offline events.
88 lines
2.3 KiB
Go
88 lines
2.3 KiB
Go
package peernotifier
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import (
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"sync"
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"github.com/lightningnetwork/lnd/subscribe"
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)
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// PeerNotifier is a subsystem which observes peer offline and online events.
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// It takes subscriptions for its events, and whenever it observes a new event
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// it notifies its subscribers over the proper channel.
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type PeerNotifier struct {
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started sync.Once
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stopped sync.Once
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ntfnServer *subscribe.Server
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}
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// PeerOnlineEvent represents a new event where a peer comes online.
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type PeerOnlineEvent struct {
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// PubKey is the peer's compressed public key.
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PubKey [33]byte
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}
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// PeerOfflineEvent represents a new event where a peer goes offline.
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type PeerOfflineEvent struct {
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// PubKey is the peer's compressed public key.
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PubKey [33]byte
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}
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// New creates a new peer notifier which notifies clients of peer online
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// and offline events.
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func New() *PeerNotifier {
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return &PeerNotifier{
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ntfnServer: subscribe.NewServer(),
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}
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}
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// Start starts the PeerNotifier's subscription server.
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func (p *PeerNotifier) Start() error {
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var err error
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p.started.Do(func() {
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log.Info("PeerNotifier starting")
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err = p.ntfnServer.Start()
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})
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return err
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}
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// Stop signals the notifier for a graceful shutdown.
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func (p *PeerNotifier) Stop() {
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p.stopped.Do(func() {
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log.Info("Stopping PeerNotifier")
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p.ntfnServer.Stop()
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})
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}
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// SubscribePeerEvents returns a subscribe.Client that will receive updates
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// any time the Server is informed of a peer event.
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func (p *PeerNotifier) SubscribePeerEvents() (*subscribe.Client, error) {
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return p.ntfnServer.Subscribe()
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}
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// NotifyPeerOnline sends a peer online event to all clients subscribed to the
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// peer notifier.
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func (p *PeerNotifier) NotifyPeerOnline(pubKey [33]byte) {
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event := PeerOnlineEvent{PubKey: pubKey}
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log.Debugf("PeerNotifier notifying peer: %x online", pubKey)
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if err := p.ntfnServer.SendUpdate(event); err != nil {
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log.Warnf("Unable to send peer online update: %v", err)
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}
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}
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// NotifyPeerOffline sends a peer offline event to all the clients subscribed
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// to the peer notifier.
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func (p *PeerNotifier) NotifyPeerOffline(pubKey [33]byte) {
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event := PeerOfflineEvent{PubKey: pubKey}
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log.Debugf("PeerNotifier notifying peer: %x offline", pubKey)
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if err := p.ntfnServer.SendUpdate(event); err != nil {
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log.Warnf("Unable to send peer offline update: %v", err)
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}
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}
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