multi: optionally connect faraday to a bitcoin node

Original chain code copied from:
e3c34449484d7dc8d505a98ea275e510651d7c3d

Co-authored-by: Oliver Gugger gugger@gmail.com

chain/client.go

@@ -0,0 +1,135 @@
+package chain
+
+import (
+	"io/ioutil"
+	"os"
+	"sync"
+
+	"github.com/btcsuite/btcd/btcjson"
+	"github.com/btcsuite/btcd/chaincfg/chainhash"
+	"github.com/btcsuite/btcd/rpcclient"
+)
+
+// BitcoinClient is an interface which represents a connection to a bitcoin
+// client.
+type BitcoinClient interface {
+	// GetTxDetail looks up a transaction.
+	GetTxDetail(txHash *chainhash.Hash) (*btcjson.TxRawResult, error)
+}
+
+// BitcoinConfig defines exported config options for the connection to the
+// btcd/bitcoind backend.
+type BitcoinConfig struct {
+	Host         string `long:"host" description:"host:port of the bitcoind/btcd instance address"`
+	User         string `long:"user" description:"bitcoind/btcd user name"`
+	Password     string `long:"password" description:"bitcoind/btcd password"`
+	HTTPPostMode bool   `long:"httppostmode" description:"Use HTTP POST mode? bitcoind only supports this mode"`
+	UseTLS       bool   `long:"usetls" description:"Use TLS to connect? bitcoind only supports non-TLS connections"`
+	TLSPath      string `long:"tlspath" description:"Path to btcd tls certificate, bitcoind only supports non-TLS connections"`
+}
+
+// DefaultConfig is the default config that we use to
+var DefaultConfig = &BitcoinConfig{
+	Host:         "localhost:8332",
+	UseTLS:       false,
+	HTTPPostMode: true,
+}
+
+// bitcoinClient is a wrapper around the RPC connection to the chain backend
+// and allows transactions to be queried.
+type bitcoinClient struct {
+	sync.Mutex
+
+	rpcClient *rpcclient.Client
+
+	// txDetailCache holds a cache of transactions we have previously looked
+	// up.
+	txDetailCache map[string]*btcjson.TxRawResult
+}
+
+// GetTxDetail fetches a single transaction from the chain and returns it
+// in a format that contains more details, like the block hash it was included
+// in for example.
+func (c *bitcoinClient) GetTxDetail(txHash *chainhash.Hash) (
+	*btcjson.TxRawResult, error) {
+
+	c.Lock()
+	cachedTx, ok := c.txDetailCache[txHash.String()]
+	c.Unlock()
+	if ok {
+		return cachedTx, nil
+	}
+
+	tx, err := c.rpcClient.GetRawTransactionVerbose(txHash)
+	if err != nil {
+		return nil, err
+	}
+
+	// Do not cache the transaction if it has not confirmed yet. If we do,
+	// we won't ever lookup the confirmed transaction because it is already
+	// cached.
+	if tx.BlockHash == "" {
+		return tx, nil
+	}
+
+	c.Lock()
+	c.txDetailCache[txHash.String()] = tx
+	c.Unlock()
+
+	return tx, nil
+}
+
+// NewBitcoinClient attempts to connect to a bitcoin rpcclient with the config
+// provided and returns a BitcoinClient wrapper which can be used to access the
+// chain connection.
+func NewBitcoinClient(cfg *BitcoinConfig) (BitcoinClient, error) {
+	client, err := getBitcoinConn(cfg)
+	if err != nil {
+		return nil, err
+	}
+
+	return &bitcoinClient{
+		rpcClient:     client,
+		txDetailCache: make(map[string]*btcjson.TxRawResult),
+	}, nil
+}
+
+// getBitcoinConn gets a bitcoin rpc client from the config details provided.
+func getBitcoinConn(cfg *BitcoinConfig) (*rpcclient.Client, error) {
+	// In case we use TLS and a certificate argument is provided, we need to
+	// read that file and provide it to the RPC connection as byte slice.
+	var rpcCert []byte
+	if cfg.UseTLS && cfg.TLSPath != "" {
+		certFile, err := os.Open(cfg.TLSPath)
+		if err != nil {
+			return nil, err
+		}
+		rpcCert, err = ioutil.ReadAll(certFile)
+		if err != nil {
+			return nil, err
+		}
+		if err := certFile.Close(); err != nil {
+			return nil, err
+		}
+	}
+
+	// Connect to bitcoin core RPC server using HTTP POST mode.
+	connCfg := &rpcclient.ConnConfig{
+		Host:         cfg.Host,
+		User:         cfg.User,
+		Pass:         cfg.Password,
+		HTTPPostMode: cfg.HTTPPostMode,
+		DisableTLS:   !cfg.UseTLS,
+		Certificates: rpcCert,
+	}
+
+	// Notice the notification parameter is nil since notifications are
+	// not supported in HTTP POST mode.
+	return rpcclient.New(connCfg, nil)
+}
+
+// Stop closes the connection to the chain backend and should always be
+// called on cleanup.
+func (c *bitcoinClient) Stop() {
+	c.rpcClient.Shutdown()
+}

config.go

@@ -5,6 +5,7 @@ import (
 	"time"
 
 	"github.com/jessevdk/go-flags"
+	"github.com/lightninglabs/faraday/chain"
 	"github.com/lightningnetwork/lnd/build"
 )
 
@@ -15,6 +16,10 @@ const (
 	defaultMinimumMonitor = time.Hour * 24 * 7 * 4 // four weeks in hours
 	defaultDebugLevel     = "info"
 	defaultRPCListen      = "localhost:8465"
+
+	// By default we do not require connecting to a bitcoin node so that
+	// we can serve basic functionality by default.
+	defaultChainConn = false
 )
 
 type Config struct {
@@ -36,6 +41,9 @@ type Config struct {
 	// Simnet is set to true when using bitcoind's regtest.
 	Regtest bool `long:"regtest" description:"Use regtest"`
 
+	// ChainConn specifies whether to attempt connecting to a bitcoin backend.
+	ChainConn bool `long:"connect_bitcoin" description:"Whether to attempt to connect to a backing bitcoin node. Some endpoints will not be available if this option is not enabled."`
+
 	// MinimumMonitored is the minimum amount of time that a channel must be monitored for before we consider it for termination.
 	MinimumMonitored time.Duration `long:"min_monitored" description:"The minimum amount of time that a channel must be monitored for before recommending termination. Valid time units are {s, m, h}."`
 
@@ -54,6 +62,9 @@ type Config struct {
 
 	// CORSOrigin specifies the CORS header that should be set on REST responses. No header is added if the value is empty.
 	CORSOrigin string `long:"corsorigin" description:"The value to send in the Access-Control-Allow-Origin header. Header will be omitted if empty."`
+
+	// Bitcoin is the configuration required to connect to a bitcoin node.
+	Bitcoin *chain.BitcoinConfig `group:"bitcoin" namespace:"bitcoin"`
 }
 
 // DefaultConfig returns all default values for the Config struct.
@@ -64,6 +75,8 @@ func DefaultConfig() Config {
 		MinimumMonitored: defaultMinimumMonitor,
 		DebugLevel:       defaultDebugLevel,
 		RPCListen:        defaultRPCListen,
+		ChainConn:        defaultChainConn,
+		Bitcoin:          chain.DefaultConfig,
 	}
 }
 
@@ -98,6 +111,21 @@ func LoadConfig() (*Config, error) {
 		return nil, fmt.Errorf("do not specify more than one network flag")
 	}
 
+	// If the user has opted into connecting to a bitcoin backend, check
+	// that we have a rpc user and password, and that tls path is set if
+	// required.
+	if config.ChainConn {
+		if config.Bitcoin.User == "" || config.Bitcoin.Password == "" {
+			return nil, fmt.Errorf("rpc user and password " +
+				"required when chainconn is set")
+		}
+
+		if config.Bitcoin.UseTLS && config.Bitcoin.TLSPath == "" {
+			return nil, fmt.Errorf("bitcoin.tlspath required " +
+				"when chainconn is set")
+		}
+	}
+
 	if err := build.ParseAndSetDebugLevels(config.DebugLevel, logWriter); err != nil {
 		return nil, err
 	}

faraday.go

@@ -4,6 +4,7 @@ package faraday
 import (
 	"fmt"
 
+	"github.com/lightninglabs/faraday/chain"
 	"github.com/lightninglabs/faraday/frdrpc"
 	"github.com/lightninglabs/lndclient"
 	"github.com/lightningnetwork/lnd/signal"
@@ -35,14 +36,22 @@ func Main() error {
 	defer client.Close()
 
 	// Instantiate the faraday gRPC server.
-	server := frdrpc.NewRPCServer(
-		&frdrpc.Config{
-			Lnd:        client.LndServices,
-			RPCListen:  config.RPCListen,
-			RESTListen: config.RESTListen,
-			CORSOrigin: config.CORSOrigin,
-		},
-	)
+	cfg := &frdrpc.Config{
+		Lnd:        client.LndServices,
+		RPCListen:  config.RPCListen,
+		RESTListen: config.RESTListen,
+		CORSOrigin: config.CORSOrigin,
+	}
+
+	// If the client chose to connect to a bitcoin client, get one now.
+	if config.ChainConn {
+		cfg.BitcoinClient, err = chain.NewBitcoinClient(config.Bitcoin)
+		if err != nil {
+			return err
+		}
+	}
+
+	server := frdrpc.NewRPCServer(cfg)
 
 	// Catch intercept signals, then start the server.
 	signal.Intercept()

frdrpc/rpcserver.go

@@ -19,6 +19,7 @@ import (
 
 	proxy "github.com/grpc-ecosystem/grpc-gateway/runtime"
 	"github.com/lightninglabs/faraday/accounting"
+	"github.com/lightninglabs/faraday/chain"
 	"github.com/lightninglabs/faraday/fiat"
 	"github.com/lightninglabs/faraday/recommend"
 	"github.com/lightninglabs/faraday/revenue"
@@ -102,6 +103,10 @@ type Config struct {
 	// CORSOrigin specifies the CORS header that should be set on REST
 	// responses. No header is added if the value is empty.
 	CORSOrigin string
+
+	// BitcoinClient is set if the client opted to connect to a bitcoin
+	// backend, if not, it will be nil.
+	BitcoinClient chain.BitcoinClient
 }
 
 // NewRPCServer returns a server which will listen for rpc requests on the