138 lines
3.6 KiB
Go
138 lines
3.6 KiB
Go
package watchtower
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import (
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"net"
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"sync/atomic"
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"github.com/lightningnetwork/lnd/brontide"
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"github.com/lightningnetwork/lnd/watchtower/lookout"
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"github.com/lightningnetwork/lnd/watchtower/wtserver"
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)
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// Standalone encapsulates the server-side functionality required by watchtower
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// clients. A Standalone couples the two primary subsystems such that, as a
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// unit, this instance can negotiate sessions with clients, accept state updates
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// for active sessions, monitor the chain for breaches matching known breach
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// hints, publish reconstructed justice transactions on behalf of tower clients.
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type Standalone struct {
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started uint32 // to be used atomically
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stopped uint32 // to be used atomically
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cfg *Config
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// server is the client endpoint, used for negotiating sessions and
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// uploading state updates.
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server wtserver.Interface
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// lookout is a service that monitors the chain and inspects the
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// transactions found in new blocks against the state updates received
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// by the server.
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lookout lookout.Service
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}
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// New validates the passed Config and returns a fresh Standalone instance if
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// the tower's subsystems could be properly initialized.
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func New(cfg *Config) (*Standalone, error) {
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// The tower must have listening address in order to accept new updates
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// from clients.
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if len(cfg.ListenAddrs) == 0 {
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return nil, ErrNoListeners
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}
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// Assign the default read timeout if none is provided.
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if cfg.ReadTimeout == 0 {
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cfg.ReadTimeout = DefaultReadTimeout
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}
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// Assign the default write timeout if none is provided.
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if cfg.WriteTimeout == 0 {
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cfg.WriteTimeout = DefaultWriteTimeout
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}
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punisher := lookout.NewBreachPunisher(&lookout.PunisherConfig{
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PublishTx: cfg.PublishTx,
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})
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// Initialize the lookout service with its required resources.
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lookout := lookout.New(&lookout.Config{
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BlockFetcher: cfg.BlockFetcher,
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DB: cfg.DB,
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EpochRegistrar: cfg.EpochRegistrar,
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Punisher: punisher,
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})
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// Create a brontide listener on each of the provided listening
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// addresses. Client should be able to connect to any of open ports to
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// communicate with this Standalone instance.
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listeners := make([]net.Listener, 0, len(cfg.ListenAddrs))
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for _, listenAddr := range cfg.ListenAddrs {
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listener, err := brontide.NewListener(
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cfg.NodePrivKey, listenAddr.String(),
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)
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if err != nil {
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return nil, err
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}
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listeners = append(listeners, listener)
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}
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// Initialize the server with its required resources.
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server, err := wtserver.New(&wtserver.Config{
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ChainHash: cfg.ChainHash,
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DB: cfg.DB,
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NodePrivKey: cfg.NodePrivKey,
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Listeners: listeners,
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ReadTimeout: cfg.ReadTimeout,
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WriteTimeout: cfg.WriteTimeout,
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NewAddress: cfg.NewAddress,
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})
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if err != nil {
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return nil, err
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}
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return &Standalone{
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cfg: cfg,
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server: server,
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lookout: lookout,
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}, nil
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}
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// Start idempotently starts the Standalone, an error is returned if the
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// subsystems could not be initialized.
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func (w *Standalone) Start() error {
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if !atomic.CompareAndSwapUint32(&w.started, 0, 1) {
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return nil
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}
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log.Infof("Starting watchtower")
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if err := w.lookout.Start(); err != nil {
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return err
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}
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if err := w.server.Start(); err != nil {
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w.lookout.Stop()
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return err
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}
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log.Infof("Watchtower started successfully")
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return nil
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}
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// Stop idempotently stops the Standalone and blocks until the subsystems have
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// completed their shutdown.
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func (w *Standalone) Stop() error {
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if !atomic.CompareAndSwapUint32(&w.stopped, 0, 1) {
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return nil
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}
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log.Infof("Stopping watchtower")
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w.server.Stop()
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w.lookout.Stop()
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log.Infof("Watchtower stopped successfully")
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return nil
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}
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