lndclient: Add watchtower client interface

Add the wtclient_client.go file which contains the lnd watchtower client
interface.

Author: Jontified

wtclient_client.go

@@ -0,0 +1,244 @@
+package lndclient
+
+import (
+	"context"
+	"time"
+
+	"github.com/lightningnetwork/lnd/lnrpc/wtclientrpc"
+	"google.golang.org/grpc"
+)
+
+// Implementation of the watchtower client interface
+// https://lightning.engineering/api-docs/category/watchtowerclient-service/
+type WatchtowerClientClient interface {
+	ServiceClient[wtclientrpc.WatchtowerClientClient]
+
+	AddTower(ctx context.Context, pubkey []byte, address string) error
+
+	// Sets the given tower's status to inactive so that it's not considered
+	// for session negotiation. Returns a human readable status string.
+	DeactivateTower(ctx context.Context, pubkey []byte) (string, error)
+
+	GetTowerInfo(ctx context.Context, pubkey []byte, includeSessions,
+		excludeExhaustedSessions bool) (*wtclientrpc.Tower, error)
+
+	ListTowers(ctx context.Context, includeSessions,
+		excludeExhaustedSessions bool) ([]*wtclientrpc.Tower, error)
+
+	Policy(ctx context.Context, policyType wtclientrpc.PolicyType) (*PolicyResponse, error)
+
+	RemoveTower(ctx context.Context, pubkey []byte, address string) error
+
+	Stats(ctx context.Context) (*StatsResponse, error)
+
+	// Terminates the given session and marks it to not be used for backups
+	// anymore. Returns a human readable status string.
+	TerminateSession(ctx context.Context, sessionId []byte) (string, error)
+}
+
+// Response returned by `Policy`
+// https://lightning.engineering/api-docs/api/lnd/watchtower-client/policy/#wtclientrpcpolicyresponse
+type PolicyResponse struct {
+	maxUpdates       uint32
+	sweepSatPerVbyte uint32
+}
+
+// Response returned by `Stats`
+// https://lightning.engineering/api-docs/api/lnd/watchtower-client/stats/#wtclientrpcstatsresponse
+type StatsResponse struct {
+	numBackups           uint32
+	numPendingBackups    uint32
+	numFailedBackups     uint32
+	numSessionsAcquired  uint32
+	numSessionsExhausted uint32
+}
+
+type wtClientClient struct {
+	client      wtclientrpc.WatchtowerClientClient
+	wtClientMac serializedMacaroon
+	timeout     time.Duration
+}
+
+// A compile time check to ensure that  wtClientClient implements the
+// WtclientClient interface.
+var _ WatchtowerClientClient = (*wtClientClient)(nil)
+
+// newClientClient creates a new watchtower client interface.
+func newWtClientClient(conn grpc.ClientConnInterface,
+	wtClientMac serializedMacaroon, timeout time.Duration) *wtClientClient {
+
+	return &wtClientClient{
+		client:      wtclientrpc.NewWatchtowerClientClient(conn),
+		wtClientMac: wtClientMac,
+		timeout:     timeout,
+	}
+}
+
+// RawClientWithMacAuth returns a context with the proper macaroon
+// authentication, the default RPC timeout, and the raw client.
+func (m *wtClientClient) RawClientWithMacAuth(
+	parentCtx context.Context) (context.Context, time.Duration,
+	wtclientrpc.WatchtowerClientClient) {
+
+	return m.wtClientMac.WithMacaroonAuth(parentCtx), m.timeout, m.client
+}
+
+// AddTower adds a new watchtower reachable at the given address and considers
+// it for new sessions. If the watchtower already exists, then any new addresses
+// included will be considered when dialing it for session negotiations and
+// backups.
+func (m *wtClientClient) AddTower(ctx context.Context, pubkey []byte, address string) error {
+	rpcCtx, cancel := context.WithTimeout(ctx, m.timeout)
+	defer cancel()
+
+	rpcReq := &wtclientrpc.AddTowerRequest{
+		Pubkey:  pubkey,
+		Address: address,
+	}
+
+	rpcCtx = m.wtClientMac.WithMacaroonAuth(rpcCtx)
+	_, err := m.client.AddTower(rpcCtx, rpcReq)
+	if err != nil {
+		return err
+	}
+
+	return nil
+}
+
+// DeactivateTower sets the given tower's status to inactive so that it is not
+// considered for session negotiation. Its sessions will also not be used while
+// the tower is inactive.
+func (m *wtClientClient) DeactivateTower(ctx context.Context, pubkey []byte) (string, error) {
+	rpcCtx, cancel := context.WithTimeout(ctx, m.timeout)
+	defer cancel()
+
+	rpcCtx = m.wtClientMac.WithMacaroonAuth(rpcCtx)
+	resp, err := m.client.DeactivateTower(rpcCtx, &wtclientrpc.DeactivateTowerRequest{
+		Pubkey: pubkey,
+	})
+	if err != nil {
+		return "", err
+	}
+
+	return resp.Status, nil
+}
+
+// GetTowerInfo gets information about a watchtower that corresponds to the
+// given pubkey. The `includeSessions` flag controls whether session information is
+// included. The `excludeExhaustedSessions` controls whether exhausted sessions
+// are included in the response.
+func (m *wtClientClient) GetTowerInfo(ctx context.Context, pubkey []byte, includeSessions,
+	excludeExhaustedSessions bool) (*wtclientrpc.Tower, error) {
+
+	rpcCtx, cancel := context.WithTimeout(ctx, m.timeout)
+	defer cancel()
+
+	rpcCtx = m.wtClientMac.WithMacaroonAuth(rpcCtx)
+	resp, err := m.client.GetTowerInfo(rpcCtx, &wtclientrpc.GetTowerInfoRequest{
+		Pubkey:                   pubkey,
+		IncludeSessions:          includeSessions,
+		ExcludeExhaustedSessions: excludeExhaustedSessions,
+	})
+	if err != nil {
+		return nil, err
+	}
+
+	return resp, nil
+}
+
+// ListTowers gets information about all registered watchtowers. The
+// `includeSessions` and `excludeExhaustedSessions` flags serve the same function as
+// in the `GetTowerInfo` method
+func (m *wtClientClient) ListTowers(ctx context.Context, includeSessions,
+	excludeExhaustedSessions bool) ([]*wtclientrpc.Tower, error) {
+
+	rpcCtx, cancel := context.WithTimeout(ctx, m.timeout)
+	defer cancel()
+
+	rpcCtx = m.wtClientMac.WithMacaroonAuth(rpcCtx)
+	resp, err := m.client.ListTowers(rpcCtx, &wtclientrpc.ListTowersRequest{
+		IncludeSessions:          includeSessions,
+		ExcludeExhaustedSessions: excludeExhaustedSessions,
+	})
+	if err != nil {
+		return nil, err
+	}
+
+	return resp.Towers, nil
+}
+
+// Policy returns the active watchtower client policy configuration.
+func (m *wtClientClient) Policy(ctx context.Context, policyType wtclientrpc.PolicyType) (*PolicyResponse, error) {
+	rpcCtx, cancel := context.WithTimeout(ctx, m.timeout)
+	defer cancel()
+
+	rpcCtx = m.wtClientMac.WithMacaroonAuth(rpcCtx)
+	resp, err := m.client.Policy(rpcCtx, &wtclientrpc.PolicyRequest{
+		PolicyType: policyType,
+	})
+	if err != nil {
+		return nil, err
+	}
+
+	return &PolicyResponse{
+		maxUpdates:       resp.MaxUpdates,
+		sweepSatPerVbyte: resp.SweepSatPerVbyte,
+	}, nil
+}
+
+// RemoveTower removes a watchtower from being considered for future session
+// negotiations and from being used for any subsequent backups until it's added
+// again. If an address is provided, then this RPC only serves as a way of
+// removing the address from the watchtower instead.
+func (m *wtClientClient) RemoveTower(ctx context.Context, pubkey []byte, address string) error {
+	rpcCtx, cancel := context.WithTimeout(ctx, m.timeout)
+	defer cancel()
+
+	rpcCtx = m.wtClientMac.WithMacaroonAuth(rpcCtx)
+	_, err := m.client.RemoveTower(rpcCtx, &wtclientrpc.RemoveTowerRequest{
+		Pubkey:  pubkey,
+		Address: address,
+	})
+	if err != nil {
+		return err
+	}
+
+	return nil
+}
+
+// Stats returns the in-memory statistics of the client since startup.
+func (m *wtClientClient) Stats(ctx context.Context) (*StatsResponse, error) {
+	rpcCtx, cancel := context.WithTimeout(ctx, m.timeout)
+	defer cancel()
+
+	rpcCtx = m.wtClientMac.WithMacaroonAuth(rpcCtx)
+	resp, err := m.client.Stats(rpcCtx, &wtclientrpc.StatsRequest{})
+	if err != nil {
+		return nil, err
+	}
+
+	return &StatsResponse{
+		numBackups:           resp.NumBackups,
+		numPendingBackups:    resp.NumPendingBackups,
+		numFailedBackups:     resp.NumFailedBackups,
+		numSessionsAcquired:  resp.NumSessionsAcquired,
+		numSessionsExhausted: resp.NumSessionsExhausted,
+	}, nil
+}
+
+// Terminate terminates the given session and marks it as terminal so that it is
+// not used for backups anymore.
+func (m *wtClientClient) TerminateSession(ctx context.Context, sessionId []byte) (string, error) {
+	rpcCtx, cancel := context.WithTimeout(ctx, m.timeout)
+	defer cancel()
+
+	rpcCtx = m.wtClientMac.WithMacaroonAuth(rpcCtx)
+	resp, err := m.client.TerminateSession(rpcCtx, &wtclientrpc.TerminateSessionRequest{
+		SessionId: sessionId,
+	})
+	if err != nil {
+		return "", err
+	}
+
+	return resp.Status, nil
+}