lnd/config_builder.go

package lnd

import (
	"context"
	"fmt"
	"path/filepath"
	"time"

	"github.com/btcsuite/btcd/chaincfg"
	"github.com/btcsuite/btclog"
	proxy "github.com/grpc-ecosystem/grpc-gateway/v2/runtime"
	"github.com/lightningnetwork/lnd/channeldb"
	"github.com/lightningnetwork/lnd/kvdb"
	"github.com/lightningnetwork/lnd/lncfg"
	"github.com/lightningnetwork/lnd/lnwallet/btcwallet"
	"github.com/lightningnetwork/lnd/macaroons"
	"github.com/lightningnetwork/lnd/watchtower"
	"github.com/lightningnetwork/lnd/watchtower/wtclient"
	"github.com/lightningnetwork/lnd/watchtower/wtdb"
	"google.golang.org/grpc"
	"gopkg.in/macaroon-bakery.v2/bakery"
)

// GrpcRegistrar is an interface that must be satisfied by an external subserver
// that wants to be able to register its own gRPC server onto lnd's main
// grpc.Server instance.
type GrpcRegistrar interface {
	// RegisterGrpcSubserver is called for each net.Listener on which lnd
	// creates a grpc.Server instance. External subservers implementing this
	// method can then register their own gRPC server structs to the main
	// server instance.
	RegisterGrpcSubserver(*grpc.Server) error
}

// RestRegistrar is an interface that must be satisfied by an external subserver
// that wants to be able to register its own REST mux onto lnd's main
// proxy.ServeMux instance.
type RestRegistrar interface {
	// RegisterRestSubserver is called after lnd creates the main
	// proxy.ServeMux instance. External subservers implementing this method
	// can then register their own REST proxy stubs to the main server
	// instance.
	RegisterRestSubserver(context.Context, *proxy.ServeMux, string,
		[]grpc.DialOption) error
}

// ExternalValidator is an interface that must be satisfied by an external
// macaroon validator.
type ExternalValidator interface {
	macaroons.MacaroonValidator

	// Permissions returns the permissions that the external validator is
	// validating. It is a map between the full HTTP URI of each RPC and its
	// required macaroon permissions. If multiple action/entity tuples are
	// specified per URI, they are all required. See rpcserver.go for a list
	// of valid action and entity values.
	Permissions() map[string][]bakery.Op
}

// DatabaseBuilder is an interface that must be satisfied by the implementation
// that provides lnd's main database backend instances.
type DatabaseBuilder interface {
	// BuildDatabase extracts the current databases that we'll use for
	// normal operation in the daemon. A function closure that closes all
	// opened databases is also returned.
	BuildDatabase(ctx context.Context) (*DatabaseInstances, func(), error)
}

// ImplementationCfg is a struct that holds all configuration items for
// components that can be implemented outside lnd itself.
type ImplementationCfg struct {
	// GrpcRegistrar is a type that can register additional gRPC subservers
	// before the main gRPC server is started.
	GrpcRegistrar

	// RestRegistrar is a type that can register additional REST subservers
	// before the main REST proxy is started.
	RestRegistrar

	// ExternalValidator is a type that can provide external macaroon
	// validation.
	ExternalValidator

	// DatabaseBuilder is a type that can provide lnd's main database
	// backend instances.
	DatabaseBuilder
}

// DefaultWalletImpl is the default implementation of our normal, btcwallet
// backed configuration.
type DefaultWalletImpl struct {
}

// RegisterRestSubserver is called after lnd creates the main proxy.ServeMux
// instance. External subservers implementing this method can then register
// their own REST proxy stubs to the main server instance.
//
// NOTE: This is part of the GrpcRegistrar interface.
func (d *DefaultWalletImpl) RegisterRestSubserver(context.Context,
	*proxy.ServeMux, string, []grpc.DialOption) error {

	return nil
}

// RegisterGrpcSubserver is called for each net.Listener on which lnd creates a
// grpc.Server instance. External subservers implementing this method can then
// register their own gRPC server structs to the main server instance.
//
// NOTE: This is part of the GrpcRegistrar interface.
func (d *DefaultWalletImpl) RegisterGrpcSubserver(*grpc.Server) error {
	return nil
}

// ValidateMacaroon extracts the macaroon from the context's gRPC metadata,
// checks its signature, makes sure all specified permissions for the called
// method are contained within and finally ensures all caveat conditions are
// met. A non-nil error is returned if any of the checks fail.
//
// NOTE: This is part of the ExternalValidator interface.
func (d *DefaultWalletImpl) ValidateMacaroon(ctx context.Context,
	requiredPermissions []bakery.Op, fullMethod string) error {

	// Because the default implementation does not return any permissions,
	// we shouldn't be registered as an external validator at all and this
	// should never be invoked.
	return fmt.Errorf("default implementation does not support external " +
		"macaroon validation")
}

// Permissions returns the permissions that the external validator is
// validating. It is a map between the full HTTP URI of each RPC and its
// required macaroon permissions. If multiple action/entity tuples are specified
// per URI, they are all required. See rpcserver.go for a list of valid action
// and entity values.
//
// NOTE: This is part of the ExternalValidator interface.
func (d *DefaultWalletImpl) Permissions() map[string][]bakery.Op {
	return nil
}

// DatabaseInstances is a struct that holds all instances to the actual
// databases that are used in lnd.
type DatabaseInstances struct {
	// GraphDB is the database that stores the channel graph used for path
	// finding.
	//
	// NOTE/TODO: This currently _needs_ to be the same instance as the
	// ChanStateDB below until the separation of the two databases is fully
	// complete!
	GraphDB *channeldb.DB

	// ChanStateDB is the database that stores all of our node's channel
	// state.
	//
	// NOTE/TODO: This currently _needs_ to be the same instance as the
	// GraphDB above until the separation of the two databases is fully
	// complete!
	ChanStateDB *channeldb.DB

	// HeightHintDB is the database that stores height hints for spends.
	HeightHintDB kvdb.Backend

	// MacaroonDB is the database that stores macaroon root keys.
	MacaroonDB kvdb.Backend

	// DecayedLogDB is the database that stores p2p related encryption
	// information.
	DecayedLogDB kvdb.Backend

	// TowerClientDB is the database that stores the watchtower client's
	// configuration.
	TowerClientDB wtclient.DB

	// TowerServerDB is the database that stores the watchtower server's
	// configuration.
	TowerServerDB watchtower.DB

	// WalletDB is the configuration for loading the wallet database using
	// the btcwallet's loader.
	WalletDB btcwallet.LoaderOption
}

// DefaultDatabaseBuilder is a type that builds the default database backends
// for lnd, using the given configuration to decide what actual implementation
// to use.
type DefaultDatabaseBuilder struct {
	cfg    *Config
	logger btclog.Logger
}

// NewDefaultDatabaseBuilder returns a new instance of the default database
// builder.
func NewDefaultDatabaseBuilder(cfg *Config,
	logger btclog.Logger) *DefaultDatabaseBuilder {

	return &DefaultDatabaseBuilder{
		cfg:    cfg,
		logger: logger,
	}
}

// BuildDatabase extracts the current databases that we'll use for normal
// operation in the daemon. A function closure that closes all opened databases
// is also returned.
func (d *DefaultDatabaseBuilder) BuildDatabase(
	ctx context.Context) (*DatabaseInstances, func(), error) {

	d.logger.Infof("Opening the main database, this might take a few " +
		"minutes...")

	cfg := d.cfg
	if cfg.DB.Backend == lncfg.BoltBackend {
		d.logger.Infof("Opening bbolt database, sync_freelist=%v, "+
			"auto_compact=%v", !cfg.DB.Bolt.NoFreelistSync,
			cfg.DB.Bolt.AutoCompact)
	}

	startOpenTime := time.Now()

	databaseBackends, err := cfg.DB.GetBackends(
		ctx, cfg.graphDatabaseDir(), cfg.networkDir, filepath.Join(
			cfg.Watchtower.TowerDir,
			cfg.registeredChains.PrimaryChain().String(),
			lncfg.NormalizeNetwork(cfg.ActiveNetParams.Name),
		), cfg.WtClient.Active, cfg.Watchtower.Active,
	)
	if err != nil {
		return nil, nil, fmt.Errorf("unable to obtain database "+
			"backends: %v", err)
	}

	// With the full remote mode we made sure both the graph and channel
	// state DB point to the same local or remote DB and the same namespace
	// within that DB.
	dbs := &DatabaseInstances{
		HeightHintDB: databaseBackends.HeightHintDB,
		MacaroonDB:   databaseBackends.MacaroonDB,
		DecayedLogDB: databaseBackends.DecayedLogDB,
		WalletDB:     databaseBackends.WalletDB,
	}
	cleanUp := func() {
		// We can just close the returned close functions directly. Even
		// if we decorate the channel DB with an additional struct, its
		// close function still just points to the kvdb backend.
		for name, closeFunc := range databaseBackends.CloseFuncs {
			if err := closeFunc(); err != nil {
				d.logger.Errorf("Error closing %s "+
					"database: %v", name, err)
			}
		}
	}
	if databaseBackends.Remote {
		d.logger.Infof("Using remote %v database! Creating "+
			"graph and channel state DB instances", cfg.DB.Backend)
	} else {
		d.logger.Infof("Creating local graph and channel state DB " +
			"instances")
	}

	dbOptions := []channeldb.OptionModifier{
		channeldb.OptionSetRejectCacheSize(cfg.Caches.RejectCacheSize),
		channeldb.OptionSetChannelCacheSize(cfg.Caches.ChannelCacheSize),
		channeldb.OptionSetBatchCommitInterval(cfg.DB.BatchCommitInterval),
		channeldb.OptionDryRunMigration(cfg.DryRunMigration),
	}

	// We want to pre-allocate the channel graph cache according to what we
	// expect for mainnet to speed up memory allocation.
	if cfg.ActiveNetParams.Name == chaincfg.MainNetParams.Name {
		dbOptions = append(
			dbOptions, channeldb.OptionSetPreAllocCacheNumNodes(
				channeldb.DefaultPreAllocCacheNumNodes,
			),
		)
	}

	// Otherwise, we'll open two instances, one for the state we only need
	// locally, and the other for things we want to ensure are replicated.
	dbs.GraphDB, err = channeldb.CreateWithBackend(
		databaseBackends.GraphDB, dbOptions...,
	)
	switch {
	// Give the DB a chance to dry run the migration. Since we know that
	// both the channel state and graph DBs are still always behind the same
	// backend, we know this would be applied to both of those DBs.
	case err == channeldb.ErrDryRunMigrationOK:
		d.logger.Infof("Graph DB dry run migration successful")
		return nil, nil, err

	case err != nil:
		cleanUp()

		err := fmt.Errorf("unable to open graph DB: %v", err)
		d.logger.Error(err)
		return nil, nil, err
	}

	// For now, we don't _actually_ split the graph and channel state DBs on
	// the code level. Since they both are based upon the *channeldb.DB
	// struct it will require more refactoring to fully separate them. With
	// the full remote mode we at least know for now that they both point to
	// the same DB backend (and also namespace within that) so we only need
	// to apply any migration once.
	//
	// TODO(guggero): Once the full separation of anything graph related
	// from the channeldb.DB is complete, the decorated instance of the
	// channel state DB should be created here individually instead of just
	// using the same struct (and DB backend) instance.
	dbs.ChanStateDB = dbs.GraphDB

	// Wrap the watchtower client DB and make sure we clean up.
	if cfg.WtClient.Active {
		dbs.TowerClientDB, err = wtdb.OpenClientDB(
			databaseBackends.TowerClientDB,
		)
		if err != nil {
			cleanUp()

			err := fmt.Errorf("unable to open %s database: %v",
				lncfg.NSTowerClientDB, err)
			d.logger.Error(err)
			return nil, nil, err
		}
	}

	// Wrap the watchtower server DB and make sure we clean up.
	if cfg.Watchtower.Active {
		dbs.TowerServerDB, err = wtdb.OpenTowerDB(
			databaseBackends.TowerServerDB,
		)
		if err != nil {
			cleanUp()

			err := fmt.Errorf("unable to open %s database: %v",
				lncfg.NSTowerServerDB, err)
			d.logger.Error(err)
			return nil, nil, err
		}
	}

	openTime := time.Since(startOpenTime)
	d.logger.Infof("Database(s) now open (time_to_open=%v)!", openTime)

	return dbs, cleanUp, nil
}