package lntest import ( "bytes" "encoding/hex" "flag" "fmt" "io" "io/ioutil" "net" "os" "os/exec" "path/filepath" "strconv" "sync" "time" "golang.org/x/net/context" "google.golang.org/grpc" "google.golang.org/grpc/credentials" macaroon "gopkg.in/macaroon.v2" "github.com/btcsuite/btcd/chaincfg" "github.com/btcsuite/btcd/chaincfg/chainhash" "github.com/btcsuite/btcd/rpcclient" "github.com/btcsuite/btcd/wire" "github.com/go-errors/errors" "github.com/lightningnetwork/lnd/lnrpc" "github.com/lightningnetwork/lnd/macaroons" ) var ( // numActiveNodes is the number of active nodes within the test network. numActiveNodes = 0 // defaultNodePort is the initial p2p port which will be used by the // first created lightning node to listen on for incoming p2p // connections. Subsequent allocated ports for future Lightning nodes // instances will be monotonically increasing numbers calculated as // such: defaultP2pPort + (3 * harness.nodeNum). defaultNodePort = 19555 // defaultClientPort is the initial rpc port which will be used by the // first created lightning node to listen on for incoming rpc // connections. Subsequent allocated ports for future rpc harness // instances will be monotonically increasing numbers calculated // as such: defaultP2pPort + (3 * harness.nodeNum). defaultClientPort = 19556 // defaultRestPort is the initial rest port which will be used by the // first created lightning node to listen on for incoming rest // connections. Subsequent allocated ports for future rpc harness // instances will be monotonically increasing numbers calculated // as such: defaultP2pPort + (3 * harness.nodeNum). defaultRestPort = 19557 // logOutput is a flag that can be set to append the output from the // seed nodes to log files. logOutput = flag.Bool("logoutput", false, "log output from node n to file outputn.log") // logPubKeyBytes is the number of bytes of the node's PubKey that // will be appended to the log file name. The whole PubKey is too // long and not really necessary to quickly identify what node // produced which log file. logPubKeyBytes = 4 // trickleDelay is the amount of time in milliseconds between each // release of announcements by AuthenticatedGossiper to the network. trickleDelay = 50 ) // generateListeningPorts returns three ints representing ports to listen on // designated for the current lightning network test. If there haven't been any // test instances created, the default ports are used. Otherwise, in order to // support multiple test nodes running at once, the p2p, rpc, and rest ports // are incremented after each initialization. func generateListeningPorts() (int, int, int) { var p2p, rpc, rest int if numActiveNodes == 0 { p2p = defaultNodePort rpc = defaultClientPort rest = defaultRestPort } else { p2p = defaultNodePort + (3 * numActiveNodes) rpc = defaultClientPort + (3 * numActiveNodes) rest = defaultRestPort + (3 * numActiveNodes) } return p2p, rpc, rest } type nodeConfig struct { Name string RPCConfig *rpcclient.ConnConfig NetParams *chaincfg.Params BaseDir string ExtraArgs []string DataDir string LogDir string TLSCertPath string TLSKeyPath string AdminMacPath string ReadMacPath string InvoiceMacPath string HasSeed bool P2PPort int RPCPort int RESTPort int } func (cfg nodeConfig) P2PAddr() string { return net.JoinHostPort("127.0.0.1", strconv.Itoa(cfg.P2PPort)) } func (cfg nodeConfig) RPCAddr() string { return net.JoinHostPort("127.0.0.1", strconv.Itoa(cfg.RPCPort)) } func (cfg nodeConfig) RESTAddr() string { return net.JoinHostPort("127.0.0.1", strconv.Itoa(cfg.RESTPort)) } func (cfg nodeConfig) DBPath() string { return filepath.Join(cfg.DataDir, "graph", "simnet/channel.db") } // genArgs generates a slice of command line arguments from the lightning node // config struct. func (cfg nodeConfig) genArgs() []string { var args []string switch cfg.NetParams { case &chaincfg.TestNet3Params: args = append(args, "--bitcoin.testnet") case &chaincfg.SimNetParams: args = append(args, "--bitcoin.simnet") case &chaincfg.RegressionNetParams: args = append(args, "--bitcoin.regtest") } encodedCert := hex.EncodeToString(cfg.RPCConfig.Certificates) args = append(args, "--bitcoin.active") args = append(args, "--nobootstrap") args = append(args, "--debuglevel=debug") args = append(args, "--bitcoin.defaultchanconfs=1") args = append(args, "--bitcoin.defaultremotedelay=4") args = append(args, fmt.Sprintf("--btcd.rpchost=%v", cfg.RPCConfig.Host)) args = append(args, fmt.Sprintf("--btcd.rpcuser=%v", cfg.RPCConfig.User)) args = append(args, fmt.Sprintf("--btcd.rpcpass=%v", cfg.RPCConfig.Pass)) args = append(args, fmt.Sprintf("--btcd.rawrpccert=%v", encodedCert)) args = append(args, fmt.Sprintf("--rpclisten=%v", cfg.RPCAddr())) args = append(args, fmt.Sprintf("--restlisten=%v", cfg.RESTAddr())) args = append(args, fmt.Sprintf("--listen=%v", cfg.P2PAddr())) args = append(args, fmt.Sprintf("--externalip=%v", cfg.P2PAddr())) args = append(args, fmt.Sprintf("--logdir=%v", cfg.LogDir)) args = append(args, fmt.Sprintf("--datadir=%v", cfg.DataDir)) args = append(args, fmt.Sprintf("--tlscertpath=%v", cfg.TLSCertPath)) args = append(args, fmt.Sprintf("--tlskeypath=%v", cfg.TLSKeyPath)) args = append(args, fmt.Sprintf("--configfile=%v", cfg.DataDir)) args = append(args, fmt.Sprintf("--adminmacaroonpath=%v", cfg.AdminMacPath)) args = append(args, fmt.Sprintf("--readonlymacaroonpath=%v", cfg.ReadMacPath)) args = append(args, fmt.Sprintf("--invoicemacaroonpath=%v", cfg.InvoiceMacPath)) args = append(args, fmt.Sprintf("--externalip=%s", cfg.P2PAddr())) args = append(args, fmt.Sprintf("--trickledelay=%v", trickleDelay)) if !cfg.HasSeed { args = append(args, "--noseedbackup") } if cfg.ExtraArgs != nil { args = append(args, cfg.ExtraArgs...) } return args } // HarnessNode represents an instance of lnd running within our test network // harness. Each HarnessNode instance also fully embeds an RPC client in // order to pragmatically drive the node. type HarnessNode struct { cfg *nodeConfig // NodeID is a unique identifier for the node within a NetworkHarness. NodeID int // PubKey is the serialized compressed identity public key of the node. // This field will only be populated once the node itself has been // started via the start() method. PubKey [33]byte PubKeyStr string cmd *exec.Cmd pidFile string logFile *os.File // processExit is a channel that's closed once it's detected that the // process this instance of HarnessNode is bound to has exited. processExit chan struct{} chanWatchRequests chan *chanWatchRequest quit chan struct{} wg sync.WaitGroup lnrpc.LightningClient lnrpc.WalletUnlockerClient } // Assert *HarnessNode implements the lnrpc.LightningClient interface. var _ lnrpc.LightningClient = (*HarnessNode)(nil) var _ lnrpc.WalletUnlockerClient = (*HarnessNode)(nil) // newNode creates a new test lightning node instance from the passed config. func newNode(cfg nodeConfig) (*HarnessNode, error) { if cfg.BaseDir == "" { var err error cfg.BaseDir, err = ioutil.TempDir("", "lndtest-node") if err != nil { return nil, err } } cfg.DataDir = filepath.Join(cfg.BaseDir, "data") cfg.LogDir = filepath.Join(cfg.BaseDir, "log") cfg.TLSCertPath = filepath.Join(cfg.DataDir, "tls.cert") cfg.TLSKeyPath = filepath.Join(cfg.DataDir, "tls.key") cfg.AdminMacPath = filepath.Join(cfg.DataDir, "admin.macaroon") cfg.ReadMacPath = filepath.Join(cfg.DataDir, "readonly.macaroon") cfg.InvoiceMacPath = filepath.Join(cfg.DataDir, "invoice.macaroon") cfg.P2PPort, cfg.RPCPort, cfg.RESTPort = generateListeningPorts() nodeNum := numActiveNodes numActiveNodes++ return &HarnessNode{ cfg: &cfg, NodeID: nodeNum, chanWatchRequests: make(chan *chanWatchRequest), }, nil } // DBPath returns the filepath to the channeldb database file for this node. func (hn *HarnessNode) DBPath() string { return hn.cfg.DBPath() } // Name returns the name of this node set during initialization. func (hn *HarnessNode) Name() string { return hn.cfg.Name } // Start launches a new process running lnd. Additionally, the PID of the // launched process is saved in order to possibly kill the process forcibly // later. // // This may not clean up properly if an error is returned, so the caller should // call shutdown() regardless of the return value. func (hn *HarnessNode) start(lndError chan<- error) error { hn.quit = make(chan struct{}) args := hn.cfg.genArgs() args = append(args, fmt.Sprintf("--profile=%d", 9000+hn.NodeID)) hn.cmd = exec.Command("./lnd-debug", args...) // Redirect stderr output to buffer var errb bytes.Buffer hn.cmd.Stderr = &errb // Make sure the log file cleanup function is initialized, even // if no log file is created. var finalizeLogfile = func() { if hn.logFile != nil { hn.logFile.Close() } } // If the logoutput flag is passed, redirect output from the nodes to // log files. if *logOutput { fileName := fmt.Sprintf("output-%d-%s-%s.log", hn.NodeID, hn.cfg.Name, hex.EncodeToString(hn.PubKey[:logPubKeyBytes])) // If the node's PubKey is not yet initialized, create a temporary // file name. Later, after the PubKey has been initialized, the // file can be moved to its final name with the PubKey included. if bytes.Equal(hn.PubKey[:4], []byte{0, 0, 0, 0}) { fileName = fmt.Sprintf("output-%d-%s-tmp__.log", hn.NodeID, hn.cfg.Name) // Once the node has done its work, the log file can be renamed. finalizeLogfile = func() { if hn.logFile != nil { hn.logFile.Close() newFileName := fmt.Sprintf("output-%d-%s-%s.log", hn.NodeID, hn.cfg.Name, hex.EncodeToString(hn.PubKey[:logPubKeyBytes])) err := os.Rename(fileName, newFileName) if err != nil { fmt.Printf("could not rename "+ "%s to %s: %v\n", fileName, newFileName, err) } } } } // Create file if not exists, otherwise append. file, err := os.OpenFile(fileName, os.O_WRONLY|os.O_APPEND|os.O_CREATE, 0666) if err != nil { return err } // Pass node's stderr to both errb and the file. w := io.MultiWriter(&errb, file) hn.cmd.Stderr = w // Pass the node's stdout only to the file. hn.cmd.Stdout = file // Let the node keep a reference to this file, such // that we can add to it if necessary. hn.logFile = file } if err := hn.cmd.Start(); err != nil { return err } // Launch a new goroutine which that bubbles up any potential fatal // process errors to the goroutine running the tests. hn.processExit = make(chan struct{}) hn.wg.Add(1) go func() { defer hn.wg.Done() err := hn.cmd.Wait() if err != nil { lndError <- errors.Errorf("%v\n%v\n", err, errb.String()) } // Signal any onlookers that this process has exited. close(hn.processExit) // Make sure log file is closed and renamed if necessary. finalizeLogfile() }() // Write process ID to a file. if err := hn.writePidFile(); err != nil { hn.cmd.Process.Kill() return err } // Since Stop uses the LightningClient to stop the node, if we fail to get a // connected client, we have to kill the process. useMacaroons := !hn.cfg.HasSeed conn, err := hn.ConnectRPC(useMacaroons) if err != nil { hn.cmd.Process.Kill() return err } // If the node was created with a seed, we will need to perform an // additional step to unlock the wallet. The connection returned will // only use the TLS certs, and can only perform operations necessary to // unlock the daemon. if hn.cfg.HasSeed { hn.WalletUnlockerClient = lnrpc.NewWalletUnlockerClient(conn) return nil } return hn.initLightningClient(conn) } // Init initializes a harness node by passing the init request via rpc. After // the request is submitted, this method will block until an // macaroon-authenticated rpc connection can be established to the harness node. // Once established, the new connection is used to initialize the // LightningClient and subscribes the HarnessNode to topology changes. func (hn *HarnessNode) Init(ctx context.Context, initReq *lnrpc.InitWalletRequest) error { timeout := time.Duration(time.Second * 15) ctxt, _ := context.WithTimeout(ctx, timeout) _, err := hn.InitWallet(ctxt, initReq) if err != nil { return err } // Wait for the wallet to finish unlocking, such that we can connect to // it via a macaroon-authenticated rpc connection. var conn *grpc.ClientConn if err = WaitPredicate(func() bool { conn, err = hn.ConnectRPC(true) return err == nil }, 5*time.Second); err != nil { return err } return hn.initLightningClient(conn) } // initLightningClient constructs the grpc LightningClient from the given client // connection and subscribes the harness node to graph topology updates. func (hn *HarnessNode) initLightningClient(conn *grpc.ClientConn) error { // Construct the LightningClient that will allow us to use the // HarnessNode directly for normal rpc operations. hn.LightningClient = lnrpc.NewLightningClient(conn) // Set the harness node's pubkey to what the node claims in GetInfo. err := hn.FetchNodeInfo() if err != nil { return err } // Launch the watcher that will hook into graph related topology change // from the PoV of this node. hn.wg.Add(1) go hn.lightningNetworkWatcher() return nil } // FetchNodeInfo queries an unlocked node to retrieve its public key. This // method also spawns a lightning network watcher for this node, which watches // for topology changes. func (hn *HarnessNode) FetchNodeInfo() error { // Obtain the lnid of this node for quick identification purposes. ctxb := context.Background() info, err := hn.GetInfo(ctxb, &lnrpc.GetInfoRequest{}) if err != nil { return err } hn.PubKeyStr = info.IdentityPubkey pubkey, err := hex.DecodeString(info.IdentityPubkey) if err != nil { return err } copy(hn.PubKey[:], pubkey) return nil } // AddToLog adds a line of choice to the node's logfile. This is useful // to interleave test output with output from the node. func (hn *HarnessNode) AddToLog(line string) error { // If this node was not set up with a log file, just return early. if hn.logFile == nil { return nil } if _, err := hn.logFile.WriteString(line); err != nil { return err } return nil } // writePidFile writes the process ID of the running lnd process to a .pid file. func (hn *HarnessNode) writePidFile() error { filePath := filepath.Join(hn.cfg.BaseDir, fmt.Sprintf("%v.pid", hn.NodeID)) pid, err := os.Create(filePath) if err != nil { return err } defer pid.Close() _, err = fmt.Fprintf(pid, "%v\n", hn.cmd.Process.Pid) if err != nil { return err } hn.pidFile = filePath return nil } // ConnectRPC uses the TLS certificate and admin macaroon files written by the // lnd node to create a gRPC client connection. func (hn *HarnessNode) ConnectRPC(useMacs bool) (*grpc.ClientConn, error) { // Wait until TLS certificate and admin macaroon are created before // using them, up to 20 sec. tlsTimeout := time.After(30 * time.Second) for !fileExists(hn.cfg.TLSCertPath) { select { case <-tlsTimeout: return nil, fmt.Errorf("timeout waiting for TLS cert " + "file to be created after 30 seconds") case <-time.After(100 * time.Millisecond): } } opts := []grpc.DialOption{ grpc.WithBlock(), grpc.WithTimeout(time.Second * 20), } tlsCreds, err := credentials.NewClientTLSFromFile(hn.cfg.TLSCertPath, "") if err != nil { return nil, err } opts = append(opts, grpc.WithTransportCredentials(tlsCreds)) if !useMacs { return grpc.Dial(hn.cfg.RPCAddr(), opts...) } macTimeout := time.After(30 * time.Second) for !fileExists(hn.cfg.AdminMacPath) { select { case <-macTimeout: return nil, fmt.Errorf("timeout waiting for admin " + "macaroon file to be created after 30 seconds") case <-time.After(100 * time.Millisecond): } } macBytes, err := ioutil.ReadFile(hn.cfg.AdminMacPath) if err != nil { return nil, err } mac := &macaroon.Macaroon{} if err = mac.UnmarshalBinary(macBytes); err != nil { return nil, err } macCred := macaroons.NewMacaroonCredential(mac) opts = append(opts, grpc.WithPerRPCCredentials(macCred)) return grpc.Dial(hn.cfg.RPCAddr(), opts...) } // SetExtraArgs assigns the ExtraArgs field for the node's configuration. The // changes will take effect on restart. func (hn *HarnessNode) SetExtraArgs(extraArgs []string) { hn.cfg.ExtraArgs = extraArgs } // cleanup cleans up all the temporary files created by the node's process. func (hn *HarnessNode) cleanup() error { return os.RemoveAll(hn.cfg.BaseDir) } // Stop attempts to stop the active lnd process. func (hn *HarnessNode) stop() error { // Do nothing if the process is not running. if hn.processExit == nil { return nil } // If start() failed before creating a client, we will just wait for the // child process to die. if hn.LightningClient != nil { // Don't watch for error because sometimes the RPC connection gets // closed before a response is returned. req := lnrpc.StopRequest{} ctx := context.Background() hn.LightningClient.StopDaemon(ctx, &req) } // Wait for lnd process and other goroutines to exit. select { case <-hn.processExit: case <-time.After(60 * time.Second): return fmt.Errorf("process did not exit") } close(hn.quit) hn.wg.Wait() hn.quit = nil hn.processExit = nil hn.LightningClient = nil hn.WalletUnlockerClient = nil return nil } // shutdown stops the active lnd process and cleans up any temporary directories // created along the way. func (hn *HarnessNode) shutdown() error { if err := hn.stop(); err != nil { return err } if err := hn.cleanup(); err != nil { return err } return nil } // closeChanWatchRequest is a request to the lightningNetworkWatcher to be // notified once it's detected within the test Lightning Network, that a // channel has either been added or closed. type chanWatchRequest struct { chanPoint wire.OutPoint chanOpen bool eventChan chan struct{} } // getChanPointFundingTxid returns the given channel point's funding txid in // raw bytes. func getChanPointFundingTxid(chanPoint *lnrpc.ChannelPoint) ([]byte, error) { var txid []byte // A channel point's funding txid can be get/set as a byte slice or a // string. In the case it is a string, decode it. switch chanPoint.GetFundingTxid().(type) { case *lnrpc.ChannelPoint_FundingTxidBytes: txid = chanPoint.GetFundingTxidBytes() case *lnrpc.ChannelPoint_FundingTxidStr: s := chanPoint.GetFundingTxidStr() h, err := chainhash.NewHashFromStr(s) if err != nil { return nil, err } txid = h[:] } return txid, nil } // lightningNetworkWatcher is a goroutine which is able to dispatch // notifications once it has been observed that a target channel has been // closed or opened within the network. In order to dispatch these // notifications, the GraphTopologySubscription client exposed as part of the // gRPC interface is used. func (hn *HarnessNode) lightningNetworkWatcher() { defer hn.wg.Done() graphUpdates := make(chan *lnrpc.GraphTopologyUpdate) hn.wg.Add(1) go func() { defer hn.wg.Done() req := &lnrpc.GraphTopologySubscription{} ctx, cancelFunc := context.WithCancel(context.Background()) topologyClient, err := hn.SubscribeChannelGraph(ctx, req) if err != nil { // We panic here in case of an error as failure to // create the topology client will cause all subsequent // tests to fail. panic(fmt.Errorf("unable to create topology "+ "client: %v", err)) } defer cancelFunc() for { update, err := topologyClient.Recv() if err == io.EOF { return } else if err != nil { return } select { case graphUpdates <- update: case <-hn.quit: return } } }() // For each outpoint, we'll track an integer which denotes the number // of edges seen for that channel within the network. When this number // reaches 2, then it means that both edge advertisements has // propagated through the network. openChans := make(map[wire.OutPoint]int) openClients := make(map[wire.OutPoint][]chan struct{}) closedChans := make(map[wire.OutPoint]struct{}) closeClients := make(map[wire.OutPoint][]chan struct{}) for { select { // A new graph update has just been received, so we'll examine // the current set of registered clients to see if we can // dispatch any requests. case graphUpdate := <-graphUpdates: // For each new channel, we'll increment the number of // edges seen by one. for _, newChan := range graphUpdate.ChannelUpdates { txidHash, _ := getChanPointFundingTxid(newChan.ChanPoint) txid, _ := chainhash.NewHash(txidHash) op := wire.OutPoint{ Hash: *txid, Index: newChan.ChanPoint.OutputIndex, } openChans[op]++ // For this new channel, if the number of edges // seen is less than two, then the channel // hasn't been fully announced yet. if numEdges := openChans[op]; numEdges < 2 { continue } // Otherwise, we'll notify all the registered // clients and remove the dispatched clients. for _, eventChan := range openClients[op] { close(eventChan) } delete(openClients, op) } // For each channel closed, we'll mark that we've // detected a channel closure while lnd was pruning the // channel graph. for _, closedChan := range graphUpdate.ClosedChans { txidHash, _ := getChanPointFundingTxid(closedChan.ChanPoint) txid, _ := chainhash.NewHash(txidHash) op := wire.OutPoint{ Hash: *txid, Index: closedChan.ChanPoint.OutputIndex, } closedChans[op] = struct{}{} // As the channel has been closed, we'll notify // all register clients. for _, eventChan := range closeClients[op] { close(eventChan) } delete(closeClients, op) } // A new watch request, has just arrived. We'll either be able // to dispatch immediately, or need to add the client for // processing later. case watchRequest := <-hn.chanWatchRequests: targetChan := watchRequest.chanPoint // TODO(roasbeef): add update type also, checks for // multiple of 2 if watchRequest.chanOpen { // If this is an open request, then it can be // dispatched if the number of edges seen for // the channel is at least two. if numEdges := openChans[targetChan]; numEdges >= 2 { close(watchRequest.eventChan) continue } // Otherwise, we'll add this to the list of // watch open clients for this out point. openClients[targetChan] = append(openClients[targetChan], watchRequest.eventChan) continue } // If this is a close request, then it can be // immediately dispatched if we've already seen a // channel closure for this channel. if _, ok := closedChans[targetChan]; ok { close(watchRequest.eventChan) continue } // Otherwise, we'll add this to the list of close watch // clients for this out point. closeClients[targetChan] = append(closeClients[targetChan], watchRequest.eventChan) case <-hn.quit: return } } } // WaitForNetworkChannelOpen will block until a channel with the target // outpoint is seen as being fully advertised within the network. A channel is // considered "fully advertised" once both of its directional edges has been // advertised within the test Lightning Network. func (hn *HarnessNode) WaitForNetworkChannelOpen(ctx context.Context, op *lnrpc.ChannelPoint) error { eventChan := make(chan struct{}) txidHash, err := getChanPointFundingTxid(op) if err != nil { return err } txid, err := chainhash.NewHash(txidHash) if err != nil { return err } hn.chanWatchRequests <- &chanWatchRequest{ chanPoint: wire.OutPoint{ Hash: *txid, Index: op.OutputIndex, }, eventChan: eventChan, chanOpen: true, } select { case <-eventChan: return nil case <-ctx.Done(): return fmt.Errorf("channel not opened before timeout") } } // WaitForNetworkChannelClose will block until a channel with the target // outpoint is seen as closed within the network. A channel is considered // closed once a transaction spending the funding outpoint is seen within a // confirmed block. func (hn *HarnessNode) WaitForNetworkChannelClose(ctx context.Context, op *lnrpc.ChannelPoint) error { eventChan := make(chan struct{}) txidHash, err := getChanPointFundingTxid(op) if err != nil { return err } txid, err := chainhash.NewHash(txidHash) if err != nil { return err } hn.chanWatchRequests <- &chanWatchRequest{ chanPoint: wire.OutPoint{ Hash: *txid, Index: op.OutputIndex, }, eventChan: eventChan, chanOpen: false, } select { case <-eventChan: return nil case <-ctx.Done(): return fmt.Errorf("channel not closed before timeout") } } // WaitForBlockchainSync will block until the target nodes has fully // synchronized with the blockchain. If the passed context object has a set // timeout, then the goroutine will continually poll until the timeout has // elapsed. In the case that the chain isn't synced before the timeout is up, // then this function will return an error. func (hn *HarnessNode) WaitForBlockchainSync(ctx context.Context) error { errChan := make(chan error, 1) retryDelay := time.Millisecond * 100 go func() { for { select { case <-ctx.Done(): case <-hn.quit: return default: } getInfoReq := &lnrpc.GetInfoRequest{} getInfoResp, err := hn.GetInfo(ctx, getInfoReq) if err != nil { errChan <- err return } if getInfoResp.SyncedToChain { errChan <- nil return } select { case <-ctx.Done(): return case <-time.After(retryDelay): } } }() select { case <-hn.quit: return nil case err := <-errChan: return err case <-ctx.Done(): return fmt.Errorf("Timeout while waiting for blockchain sync") } } // WaitForBalance waits until the node sees the expected confirmed/unconfirmed // balance within their wallet. func (hn *HarnessNode) WaitForBalance(expectedBalance int64, confirmed bool) error { ctx := context.Background() req := &lnrpc.WalletBalanceRequest{} doesBalanceMatch := func() bool { balance, err := hn.WalletBalance(ctx, req) if err != nil { return false } if confirmed { return balance.ConfirmedBalance == expectedBalance } return balance.UnconfirmedBalance == expectedBalance } err := WaitPredicate(doesBalanceMatch, 30*time.Second) if err != nil { return errors.New("balances not synced after deadline") } return nil } // fileExists reports whether the named file or directory exists. // This function is taken from https://github.com/btcsuite/btcd func fileExists(name string) bool { if _, err := os.Stat(name); err != nil { if os.IsNotExist(err) { return false } } return true }