12585581807

Committed 02 Jan 2025 04:32PM UTC coverage: 58.678% (+0.08%) from 58.598%

Build # 12585581807

Build Type

Pull #9395

github

Committed by

mohamedawnallah

Commit Message

multi: manage shutdown requests with status codes

In this commit, we manage shutdown requests with status
codes. Exits with code 1 for critical errors
(e.g, from exhausted attempts connecting to chain backend),
and code 0 for normal shutdowns (e.g., from Stop Daemon RPC call).

Co-authored-by: Elle Mouton <elle.mouton@gmail.com>

Pull Request Pull Request #9395: multi: manage shutdown requests with status codes

Run Details

14 of 27 new or added lines in 5 files covered. (51.85%)

23 existing lines in 9 files now uncovered.

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Source File
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58.22

/lnd.go

// Copyright (c) 2013-2017 The btcsuite developers
// Copyright (c) 2015-2016 The Decred developers
// Copyright (C) 2015-2022 The Lightning Network Developers

package lnd

import (
        "context"
        "errors"
        "fmt"
        "log/slog"
        "net"
        "net/http"
        "net/http/pprof"
        "os"
        "runtime"
        runtimePprof "runtime/pprof"
        "strings"
        "sync"
        "time"

        "github.com/btcsuite/btcd/btcutil"
        proxy "github.com/grpc-ecosystem/grpc-gateway/v2/runtime"
        "github.com/lightningnetwork/lnd/autopilot"
        "github.com/lightningnetwork/lnd/build"
        "github.com/lightningnetwork/lnd/chanacceptor"
        "github.com/lightningnetwork/lnd/channeldb"
        "github.com/lightningnetwork/lnd/cluster"
        "github.com/lightningnetwork/lnd/keychain"
        "github.com/lightningnetwork/lnd/lncfg"
        "github.com/lightningnetwork/lnd/lnrpc"
        "github.com/lightningnetwork/lnd/lnwallet"
        "github.com/lightningnetwork/lnd/macaroons"
        "github.com/lightningnetwork/lnd/monitoring"
        "github.com/lightningnetwork/lnd/rpcperms"
        "github.com/lightningnetwork/lnd/signal"
        "github.com/lightningnetwork/lnd/tor"
        "github.com/lightningnetwork/lnd/walletunlocker"
        "github.com/lightningnetwork/lnd/watchtower"
        "google.golang.org/grpc"
        "google.golang.org/grpc/credentials"
        "google.golang.org/grpc/keepalive"
        "gopkg.in/macaroon-bakery.v2/bakery"
        "gopkg.in/macaroon.v2"
)

const (
        // adminMacaroonFilePermissions is the file permission that is used for
        // creating the admin macaroon file.
        //
        // Why 640 is safe:
        // Assuming a reasonably secure Linux system, it will have a
        // separate group for each user. E.g. a new user lnd gets assigned group
        // lnd which nothing else belongs to. A system that does not do this is
        // inherently broken already.
        //
        // Since there is no other user in the group, no other user can read
        // admin macaroon unless the administrator explicitly allowed it. Thus
        // there's no harm allowing group read.
        adminMacaroonFilePermissions = 0640

        // leaderResignTimeout is the timeout used when resigning from the
        // leader role. This is kept short so LND can shut down quickly in case
        // of a system failure or network partition making the cluster
        // unresponsive. The cluster itself should ensure that the leader is not
        // elected again until the previous leader has resigned or the leader
        // election timeout has passed.
        leaderResignTimeout = 5 * time.Second
)

// AdminAuthOptions returns a list of DialOptions that can be used to
// authenticate with the RPC server with admin capabilities.
// skipMacaroons=true should be set if we don't want to include macaroons with
// the auth options. This is needed for instance for the WalletUnlocker
// service, which must be usable also before macaroons are created.
//
// NOTE: This should only be called after the RPCListener has signaled it is
// ready.
func AdminAuthOptions(cfg *Config, skipMacaroons bool) ([]grpc.DialOption,
        error) {

        creds, err := credentials.NewClientTLSFromFile(cfg.TLSCertPath, "")
        if err != nil {
                return nil, fmt.Errorf("unable to read TLS cert: %w", err)
        }

        // Create a dial options array.
        opts := []grpc.DialOption{
                grpc.WithTransportCredentials(creds),
        }

        // Get the admin macaroon if macaroons are active.
        if !skipMacaroons && !cfg.NoMacaroons {
                // Load the admin macaroon file.
                macBytes, err := os.ReadFile(cfg.AdminMacPath)
                if err != nil {
                        return nil, fmt.Errorf("unable to read macaroon "+
                                "path (check the network setting!): %v", err)
                }

                mac := &macaroon.Macaroon{}
                if err = mac.UnmarshalBinary(macBytes); err != nil {
                        return nil, fmt.Errorf("unable to decode macaroon: %w",
                                err)
                }

                // Now we append the macaroon credentials to the dial options.
                cred, err := macaroons.NewMacaroonCredential(mac)
                if err != nil {
                        return nil, fmt.Errorf("error cloning mac: %w", err)
                }
                opts = append(opts, grpc.WithPerRPCCredentials(cred))
        }

        return opts, nil
}

// ListenerWithSignal is a net.Listener that has an additional Ready channel
// that will be closed when a server starts listening.
type ListenerWithSignal struct {
        net.Listener

        // Ready will be closed by the server listening on Listener.
        Ready chan struct{}

        // MacChan is an optional way to pass the admin macaroon to the program
        // that started lnd. The channel should be buffered to avoid lnd being
        // blocked on sending to the channel.
        MacChan chan []byte
}

// ListenerCfg is a wrapper around custom listeners that can be passed to lnd
// when calling its main method.
type ListenerCfg struct {
        // RPCListeners can be set to the listeners to use for the RPC server.
        // If empty a regular network listener will be created.
        RPCListeners []*ListenerWithSignal
}

var errStreamIsolationWithProxySkip = errors.New(
        "while stream isolation is enabled, the TOR proxy may not be skipped",
)

// Main is the true entry point for lnd. It accepts a fully populated and
// validated main configuration struct and an optional listener config struct.
// This function starts all main system components then blocks until a signal
// is received on the shutdownChan at which point everything is shut down again.
func Main(cfg *Config, lisCfg ListenerCfg, implCfg *ImplementationCfg,
        interceptor signal.Interceptor) error {

        defer func() {
                ltndLog.Info("Shutdown complete")
                err := cfg.LogRotator.Close()
                if err != nil {
                        ltndLog.Errorf("Could not close log rotator: %v", err)
                }
        }()

        ctx, cancel := context.WithCancel(context.Background())
        defer cancel()

        ctx, err := build.WithBuildInfo(ctx, cfg.LogConfig)
        if err != nil {
                return fmt.Errorf("unable to add build info to context: %w",
                        err)
        }

        mkErr := func(msg string, err error, attrs ...any) error {
                ltndLog.ErrorS(ctx, "Shutting down due to error in main "+
                        "method", err, attrs...)

                var (
                        params = []any{err}
                        fmtStr = msg + ": %w"
                )
                for _, attr := range attrs {
                        fmtStr += " %s"

                        params = append(params, attr)
                }

                return fmt.Errorf(fmtStr, params...)
        }

        // Show version at startup.
        ltndLog.InfoS(ctx, "Version Info",
                slog.String("version", build.Version()),
                slog.String("commit", build.Commit),
                slog.Any("debuglevel", build.Deployment),
                slog.String("logging", cfg.DebugLevel))

        var network string
        switch {
        case cfg.Bitcoin.TestNet3:
                network = "testnet"

        case cfg.Bitcoin.MainNet:
                network = "mainnet"

        case cfg.Bitcoin.SimNet:
                network = "simnet"

        case cfg.Bitcoin.RegTest:
                network = "regtest"

        case cfg.Bitcoin.SigNet:
                network = "signet"
        }

        ltndLog.InfoS(ctx, "Network Info",
                "active_chain", strings.Title(BitcoinChainName),
                "network", network)

        // Enable http profiling server if requested.
        if cfg.Pprof.Profile != "" {
                // Create the http handler.
                pprofMux := http.NewServeMux()
                pprofMux.HandleFunc("/debug/pprof/", pprof.Index)
                pprofMux.HandleFunc("/debug/pprof/cmdline", pprof.Cmdline)
                pprofMux.HandleFunc("/debug/pprof/profile", pprof.Profile)
                pprofMux.HandleFunc("/debug/pprof/symbol", pprof.Symbol)
                pprofMux.HandleFunc("/debug/pprof/trace", pprof.Trace)

                if cfg.Pprof.BlockingProfile != 0 {
                        runtime.SetBlockProfileRate(cfg.Pprof.BlockingProfile)
                }
                if cfg.Pprof.MutexProfile != 0 {
                        runtime.SetMutexProfileFraction(cfg.Pprof.MutexProfile)
                }

                // Redirect all requests to the pprof handler, thus visiting
                // `127.0.0.1:6060` will be redirected to
                // `127.0.0.1:6060/debug/pprof`.
                pprofMux.Handle("/", http.RedirectHandler(
                        "/debug/pprof/", http.StatusSeeOther,
                ))

                ltndLog.InfoS(ctx, "Pprof listening", "addr", cfg.Pprof.Profile)

                // Create the pprof server.
                pprofServer := &http.Server{
                        Addr:              cfg.Pprof.Profile,
                        Handler:           pprofMux,
                        ReadHeaderTimeout: cfg.HTTPHeaderTimeout,
                }

                // Shut the server down when lnd is shutting down.
                defer func() {
                        ltndLog.InfoS(ctx, "Stopping pprof server...")
                        err := pprofServer.Shutdown(ctx)
                        if err != nil {
                                ltndLog.ErrorS(ctx, "Stop pprof server", err)
                        }
                }()

                // Start the pprof server.
                go func() {
                        err := pprofServer.ListenAndServe()
                        if err != nil && !errors.Is(err, http.ErrServerClosed) {
                                ltndLog.ErrorS(ctx, "Could not serve pprof "+
                                        "server", err)
                        }
                }()
        }

        // Write cpu profile if requested.
        if cfg.Pprof.CPUProfile != "" {
                f, err := os.Create(cfg.Pprof.CPUProfile)
                if err != nil {
                        return mkErr("unable to create CPU profile", err)
                }
                _ = runtimePprof.StartCPUProfile(f)
                defer func() {
                        _ = f.Close()
                }()
                defer runtimePprof.StopCPUProfile()
        }

        // Run configuration dependent DB pre-initialization. Note that this
        // needs to be done early and once during the startup process, before
        // any DB access.
        if err := cfg.DB.Init(ctx, cfg.graphDatabaseDir()); err != nil {
                return mkErr("error initializing DBs", err)
        }

        tlsManagerCfg := &TLSManagerCfg{
                TLSCertPath:        cfg.TLSCertPath,
                TLSKeyPath:         cfg.TLSKeyPath,
                TLSEncryptKey:      cfg.TLSEncryptKey,
                TLSExtraIPs:        cfg.TLSExtraIPs,
                TLSExtraDomains:    cfg.TLSExtraDomains,
                TLSAutoRefresh:     cfg.TLSAutoRefresh,
                TLSDisableAutofill: cfg.TLSDisableAutofill,
                TLSCertDuration:    cfg.TLSCertDuration,

                LetsEncryptDir:    cfg.LetsEncryptDir,
                LetsEncryptDomain: cfg.LetsEncryptDomain,
                LetsEncryptListen: cfg.LetsEncryptListen,

                DisableRestTLS: cfg.DisableRestTLS,

                HTTPHeaderTimeout: cfg.HTTPHeaderTimeout,
        }
        tlsManager := NewTLSManager(tlsManagerCfg)
        serverOpts, restDialOpts, restListen, cleanUp,
                err := tlsManager.SetCertificateBeforeUnlock()
        if err != nil {
                return mkErr("error setting cert before unlock", err)
        }
        if cleanUp != nil {
                defer cleanUp()
        }

        // If we have chosen to start with a dedicated listener for the
        // rpc server, we set it directly.
        grpcListeners := append([]*ListenerWithSignal{}, lisCfg.RPCListeners...)
        if len(grpcListeners) == 0 {
                // Otherwise we create listeners from the RPCListeners defined
                // in the config.
                for _, grpcEndpoint := range cfg.RPCListeners {
                        // Start a gRPC server listening for HTTP/2
                        // connections.
                        lis, err := lncfg.ListenOnAddress(grpcEndpoint)
                        if err != nil {
                                return mkErr("unable to listen on grpc "+
                                        "endpoint", err,
                                        slog.String(
                                                "endpoint",
                                                grpcEndpoint.String(),
                                        ))
                        }
                        defer lis.Close()

                        grpcListeners = append(
                                grpcListeners, &ListenerWithSignal{
                                        Listener: lis,
                                        Ready:    make(chan struct{}),
                                },
                        )
                }
        }

        // Create a new RPC interceptor that we'll add to the GRPC server. This
        // will be used to log the API calls invoked on the GRPC server.
        interceptorChain := rpcperms.NewInterceptorChain(
                rpcsLog, cfg.NoMacaroons, cfg.RPCMiddleware.Mandatory,
        )
        if err := interceptorChain.Start(); err != nil {
                return mkErr("error starting interceptor chain", err)
        }
        defer func() {
                err := interceptorChain.Stop()
                if err != nil {
                        ltndLog.Warnf("error stopping RPC interceptor "+
                                "chain: %v", err)
                }
        }()

        // Allow the user to overwrite some defaults of the gRPC library related
        // to connection keepalive (server side and client side pings).
        serverKeepalive := keepalive.ServerParameters{
                Time:    cfg.GRPC.ServerPingTime,
                Timeout: cfg.GRPC.ServerPingTimeout,
        }
        clientKeepalive := keepalive.EnforcementPolicy{
                MinTime:             cfg.GRPC.ClientPingMinWait,
                PermitWithoutStream: cfg.GRPC.ClientAllowPingWithoutStream,
        }

        rpcServerOpts := interceptorChain.CreateServerOpts()
        serverOpts = append(serverOpts, rpcServerOpts...)
        serverOpts = append(
                serverOpts, grpc.MaxRecvMsgSize(lnrpc.MaxGrpcMsgSize),
                grpc.KeepaliveParams(serverKeepalive),
                grpc.KeepaliveEnforcementPolicy(clientKeepalive),
        )

        grpcServer := grpc.NewServer(serverOpts...)
        defer grpcServer.Stop()

        // We'll also register the RPC interceptor chain as the StateServer, as
        // it can be used to query for the current state of the wallet.
        lnrpc.RegisterStateServer(grpcServer, interceptorChain)

        // Initialize, and register our implementation of the gRPC interface
        // exported by the rpcServer.
        rpcServer := newRPCServer(cfg, interceptorChain, implCfg, interceptor)
        err = rpcServer.RegisterWithGrpcServer(grpcServer)
        if err != nil {
                return mkErr("error registering gRPC server", err)
        }

        // Now that both the WalletUnlocker and LightningService have been
        // registered with the GRPC server, we can start listening.
        err = startGrpcListen(cfg, grpcServer, grpcListeners)
        if err != nil {
                return mkErr("error starting gRPC listener", err)
        }

        // Now start the REST proxy for our gRPC server above. We'll ensure
        // we direct LND to connect to its loopback address rather than a
        // wildcard to prevent certificate issues when accessing the proxy
        // externally.
        stopProxy, err := startRestProxy(
                ctx, cfg, rpcServer, restDialOpts, restListen,
        )
        if err != nil {
                return mkErr("error starting REST proxy", err)
        }
        defer stopProxy()

        // Start leader election if we're running on etcd. Continuation will be
        // blocked until this instance is elected as the current leader or
        // shutting down.
        elected, leaderNormalShutdown := false, false
        var leaderElector cluster.LeaderElector
        if cfg.Cluster.EnableLeaderElection {
                electionCtx, cancelElection := context.WithCancel(ctx)

                go func() {
                        leaderNormalShutdown = <-interceptor.ShutdownChannel()
                        cancelElection()
                }()

                ltndLog.InfoS(ctx, "Using leader elector",
                        "elector", cfg.Cluster.LeaderElector)

                leaderElector, err = cfg.Cluster.MakeLeaderElector(
                        electionCtx, cfg.DB,
                )
                if err != nil {
                        return err
                }

                defer func() {
                        if !elected {
                                return
                        }

                        ltndLog.InfoS(ctx, "Attempting to resign from "+
                                "leader role", "cluster_id", cfg.Cluster.ID)

                        // Ensure that we don't block the shutdown process if
                        // the leader resigning process takes too long. The
                        // cluster will ensure that the leader is not elected
                        // again until the previous leader has resigned or the
                        // leader election timeout has passed.
                        timeoutCtx, cancel := context.WithTimeout(
                                ctx, leaderResignTimeout,
                        )
                        defer cancel()

                        if err := leaderElector.Resign(timeoutCtx); err != nil {
                                ltndLog.Errorf("Leader elector failed to "+
                                        "resign: %v", err)
                        }
                }()

                ltndLog.InfoS(ctx, "Starting leadership campaign",
                        "cluster_id", cfg.Cluster.ID)

                if err := leaderElector.Campaign(electionCtx); err != nil {
                        return mkErr("leadership campaign failed", err)
                }

                elected = true
                ltndLog.InfoS(ctx, "Elected as leader",
                        "cluster_id", cfg.Cluster.ID)
        }

        dbs, cleanUp, err := implCfg.DatabaseBuilder.BuildDatabase(ctx)
        switch {
        case errors.Is(err, channeldb.ErrDryRunMigrationOK):
                ltndLog.InfoS(ctx, "Exiting due to BuildDatabase error",
                        slog.Any("err", err))
                return nil
        case err != nil:
                return mkErr("unable to open databases", err)
        }

        defer cleanUp()

        partialChainControl, walletConfig, cleanUp, err := implCfg.BuildWalletConfig(
                ctx, dbs, &implCfg.AuxComponents, interceptorChain,
                grpcListeners,
        )
        if err != nil {
                return mkErr("error creating wallet config", err)
        }

        defer cleanUp()

        activeChainControl, cleanUp, err := implCfg.BuildChainControl(
                partialChainControl, walletConfig,
        )
        if err != nil {
                return mkErr("error loading chain control", err)
        }

        defer cleanUp()

        // TODO(roasbeef): add rotation
        idKeyDesc, err := activeChainControl.KeyRing.DeriveKey(
                keychain.KeyLocator{
                        Family: keychain.KeyFamilyNodeKey,
                        Index:  0,
                },
        )
        if err != nil {
                return mkErr("error deriving node key", err)
        }

        if cfg.Tor.StreamIsolation && cfg.Tor.SkipProxyForClearNetTargets {
                return errStreamIsolationWithProxySkip
        }

        if cfg.Tor.Active {
                if cfg.Tor.SkipProxyForClearNetTargets {
                        srvrLog.InfoS(ctx, "Onion services are accessible "+
                                "via Tor! NOTE: Traffic to clearnet services "+
                                "is not routed via Tor.")
                } else {
                        srvrLog.InfoS(ctx, "Proxying all network traffic "+
                                "via Tor! NOTE: Ensure the backend node is "+
                                "proxying over Tor as well",
                                "stream_isolation", cfg.Tor.StreamIsolation)
                }
        }

        // If tor is active and either v2 or v3 onion services have been
        // specified, make a tor controller and pass it into both the watchtower
        // server and the regular lnd server.
        var torController *tor.Controller
        if cfg.Tor.Active && (cfg.Tor.V2 || cfg.Tor.V3) {
                torController = tor.NewController(
                        cfg.Tor.Control, cfg.Tor.TargetIPAddress,
                        cfg.Tor.Password,
                )

                // Start the tor controller before giving it to any other
                // subsystems.
                if err := torController.Start(); err != nil {
                        return mkErr("unable to initialize tor controller",
                                err)
                }
                defer func() {
                        if err := torController.Stop(); err != nil {
                                ltndLog.ErrorS(ctx, "Error stopping tor "+
                                        "controller", err)
                        }
                }()
        }

        var tower *watchtower.Standalone
        if cfg.Watchtower.Active {
                towerKeyDesc, err := activeChainControl.KeyRing.DeriveKey(
                        keychain.KeyLocator{
                                Family: keychain.KeyFamilyTowerID,
                                Index:  0,
                        },
                )
                if err != nil {
                        return mkErr("error deriving tower key", err)
                }

                wtCfg := &watchtower.Config{
                        BlockFetcher:   activeChainControl.ChainIO,
                        DB:             dbs.TowerServerDB,
                        EpochRegistrar: activeChainControl.ChainNotifier,
                        Net:            cfg.net,
                        NewAddress: func() (btcutil.Address, error) {
                                return activeChainControl.Wallet.NewAddress(
                                        lnwallet.TaprootPubkey, false,
                                        lnwallet.DefaultAccountName,
                                )
                        },
                        NodeKeyECDH: keychain.NewPubKeyECDH(
                                towerKeyDesc, activeChainControl.KeyRing,
                        ),
                        PublishTx: activeChainControl.Wallet.PublishTransaction,
                        ChainHash: *cfg.ActiveNetParams.GenesisHash,
                }

                // If there is a tor controller (user wants auto hidden
                // services), then store a pointer in the watchtower config.
                if torController != nil {
                        wtCfg.TorController = torController
                        wtCfg.WatchtowerKeyPath = cfg.Tor.WatchtowerKeyPath
                        wtCfg.EncryptKey = cfg.Tor.EncryptKey
                        wtCfg.KeyRing = activeChainControl.KeyRing

                        switch {
                        case cfg.Tor.V2:
                                wtCfg.Type = tor.V2
                        case cfg.Tor.V3:
                                wtCfg.Type = tor.V3
                        }
                }

                wtConfig, err := cfg.Watchtower.Apply(
                        wtCfg, lncfg.NormalizeAddresses,
                )
                if err != nil {
                        return mkErr("unable to configure watchtower", err)
                }

                tower, err = watchtower.New(wtConfig)
                if err != nil {
                        return mkErr("unable to create watchtower", err)
                }
        }

        // Initialize the MultiplexAcceptor. If lnd was started with the
        // zero-conf feature bit, then this will be a ZeroConfAcceptor.
        // Otherwise, this will be a ChainedAcceptor.
        var multiAcceptor chanacceptor.MultiplexAcceptor
        if cfg.ProtocolOptions.ZeroConf() {
                multiAcceptor = chanacceptor.NewZeroConfAcceptor()
        } else {
                multiAcceptor = chanacceptor.NewChainedAcceptor()
        }

        // Set up the core server which will listen for incoming peer
        // connections.
        server, err := newServer(
                cfg, cfg.Listeners, dbs, activeChainControl, &idKeyDesc,
                activeChainControl.Cfg.WalletUnlockParams.ChansToRestore,
                multiAcceptor, torController, tlsManager, leaderElector,
                implCfg,
        )
        if err != nil {
                return mkErr("unable to create server", err)
        }

        // Set up an autopilot manager from the current config. This will be
        // used to manage the underlying autopilot agent, starting and stopping
        // it at will.
        atplCfg, err := initAutoPilot(
                server, cfg.Autopilot, activeChainControl.MinHtlcIn,
                cfg.ActiveNetParams,
        )
        if err != nil {
                return mkErr("unable to initialize autopilot", err)
        }

        atplManager, err := autopilot.NewManager(atplCfg)
        if err != nil {
                return mkErr("unable to create autopilot manager", err)
        }
        if err := atplManager.Start(); err != nil {
                return mkErr("unable to start autopilot manager", err)
        }
        defer atplManager.Stop()

        err = tlsManager.LoadPermanentCertificate(activeChainControl.KeyRing)
        if err != nil {
                return mkErr("unable to load permanent TLS certificate", err)
        }

        // Now we have created all dependencies necessary to populate and
        // start the RPC server.
        err = rpcServer.addDeps(
                server, interceptorChain.MacaroonService(), cfg.SubRPCServers,
                atplManager, server.invoices, tower, multiAcceptor,
                server.invoiceHtlcModifier,
        )
        if err != nil {
                return mkErr("unable to add deps to RPC server", err)
        }
        if err := rpcServer.Start(); err != nil {
                return mkErr("unable to start RPC server", err)
        }
        defer rpcServer.Stop()

        // We transition the RPC state to Active, as the RPC server is up.
        interceptorChain.SetRPCActive()

        if err := interceptor.Notifier.NotifyReady(true); err != nil {
                return mkErr("error notifying ready", err)
        }

        // We'll wait until we're fully synced to continue the start up of the
        // remainder of the daemon. This ensures that we don't accept any
        // possibly invalid state transitions, or accept channels with spent
        // funds.
        _, bestHeight, err := activeChainControl.ChainIO.GetBestBlock()
        if err != nil {
                return mkErr("unable to determine chain tip", err)
        }

        ltndLog.InfoS(ctx, "Waiting for chain backend to finish sync",
                slog.Int64("start_height", int64(bestHeight)))

        type syncResult struct {
                synced        bool
                bestBlockTime int64
                err           error
        }

        var syncedResChan = make(chan syncResult, 1)

        for {
                // We check if the wallet is synced in a separate goroutine as
                // the call is blocking, and we want to be able to interrupt it
                // if the daemon is shutting down.
                go func() {
                        synced, bestBlockTime, err := activeChainControl.Wallet.
                                IsSynced()
                        syncedResChan <- syncResult{synced, bestBlockTime, err}
                }()

                select {
                case <-interceptor.ShutdownChannel():
                        return nil

                case res := <-syncedResChan:
                        if res.err != nil {
                                return mkErr("unable to determine if wallet "+
                                        "is synced", res.err)
                        }

                        ltndLog.DebugS(ctx, "Syncing to block chain",
                                "best_block_time", time.Unix(res.bestBlockTime, 0),
                                "is_synced", res.synced)

                        if res.synced {
                                break
                        }

                        // If we're not yet synced, we'll wait for a second
                        // before checking again.
                        select {
                        case <-interceptor.ShutdownChannel():
                                return nil

                        case <-time.After(time.Second):
                                continue
                        }
                }

                break
        }

        _, bestHeight, err = activeChainControl.ChainIO.GetBestBlock()
        if err != nil {
                return mkErr("unable to determine chain tip", err)
        }

        ltndLog.InfoS(ctx, "Chain backend is fully synced!",
                "end_height", bestHeight)

        // With all the relevant chains initialized, we can finally start the
        // server itself. We start the server in an asynchronous goroutine so
        // that we are able to interrupt and shutdown the daemon gracefully in
        // case the startup of the subservers do not behave as expected.
        errChan := make(chan error)
        go func() {
                errChan <- server.Start()
        }()

        defer func() {
                err := server.Stop()
                if err != nil {
                        ltndLog.WarnS(ctx, "Stopping the server including all "+
                                "its subsystems failed with", err)
                }
        }()

        select {
        case err := <-errChan:
                if err == nil {
                        break
                }

                return mkErr("unable to start server", err)

        case <-interceptor.ShutdownChannel():
                return nil
        }

        // We transition the server state to Active, as the server is up.
        interceptorChain.SetServerActive()

        // Now that the server has started, if the autopilot mode is currently
        // active, then we'll start the autopilot agent immediately. It will be
        // stopped together with the autopilot service.
        if cfg.Autopilot.Active {
                if err := atplManager.StartAgent(); err != nil {
                        return mkErr("unable to start autopilot agent", err)
                }
        }

        if cfg.Watchtower.Active {
                if err := tower.Start(); err != nil {
                        return mkErr("unable to start watchtower", err)
                }
                defer tower.Stop()
        }

        // Wait for shutdown signal from either a graceful server stop or from
        // the interrupt handler.
        normalShutdown := <-interceptor.ShutdownChannel()
        if !(normalShutdown || leaderNormalShutdown) {
                return errors.New("LND shut down with an error")
        }

        return nil
}

// bakeMacaroon creates a new macaroon with newest version and the given
// permissions then returns it binary serialized.
func bakeMacaroon(ctx context.Context, svc *macaroons.Service,
        permissions []bakery.Op) ([]byte, error) {

        mac, err := svc.NewMacaroon(
                ctx, macaroons.DefaultRootKeyID, permissions...,
        )
        if err != nil {
                return nil, err
        }

        return mac.M().MarshalBinary()
}

// saveMacaroon bakes a macaroon with the specified macaroon permissions and
// writes it to a file with the given filename and file permissions.
func saveMacaroon(ctx context.Context, svc *macaroons.Service, filename string,
        macaroonPermissions []bakery.Op, filePermissions os.FileMode) error {

        macaroonBytes, err := bakeMacaroon(ctx, svc, macaroonPermissions)
        if err != nil {
                return err
        }
        err = os.WriteFile(filename, macaroonBytes, filePermissions)
        if err != nil {
                _ = os.Remove(filename)
                return err
        }

        return nil
}

// genDefaultMacaroons checks for three default macaroon files and generates
// them if they do not exist; one admin-level, one for invoice access and one
// read-only. Each macaroon is checked and created independently to ensure all
// three exist. The admin macaroon can also be used to generate more granular
// macaroons.
func genDefaultMacaroons(ctx context.Context, svc *macaroons.Service,
        admFile, roFile, invoiceFile string) error {

        // First, we'll generate a macaroon that only allows the caller to
        // access invoice related calls. This is useful for merchants and other
        // services to allow an isolated instance that can only query and
        // modify invoices.
        if !lnrpc.FileExists(invoiceFile) {
                err := saveMacaroon(
                        ctx, svc, invoiceFile, invoicePermissions, 0644,
                )
                if err != nil {
                        return err
                }
        }

        // Generate the read-only macaroon and write it to a file.
        if !lnrpc.FileExists(roFile) {
                err := saveMacaroon(
                        ctx, svc, roFile, readPermissions, 0644,
                )
                if err != nil {
                        return err
                }
        }

        // Generate the admin macaroon and write it to a file.
        if !lnrpc.FileExists(admFile) {
                err := saveMacaroon(
                        ctx, svc, admFile, adminPermissions(),
                        adminMacaroonFilePermissions,
                )
                if err != nil {
                        return err
                }
        }

        return nil
}

// adminPermissions returns a list of all permissions in a safe way that doesn't
// modify any of the source lists.
func adminPermissions() []bakery.Op {
        admin := make([]bakery.Op, len(readPermissions)+len(writePermissions))
        copy(admin[:len(readPermissions)], readPermissions)
        copy(admin[len(readPermissions):], writePermissions)
        return admin
}

// createWalletUnlockerService creates a WalletUnlockerService from the passed
// config.
func createWalletUnlockerService(cfg *Config) *walletunlocker.UnlockerService {
        // The macaroonFiles are passed to the wallet unlocker so they can be
        // deleted and recreated in case the root macaroon key is also changed
        // during the change password operation.
        macaroonFiles := []string{
                cfg.AdminMacPath, cfg.ReadMacPath, cfg.InvoiceMacPath,
        }

        return walletunlocker.New(
                cfg.ActiveNetParams.Params, macaroonFiles,
                cfg.ResetWalletTransactions, nil,
        )
}

// startGrpcListen starts the GRPC server on the passed listeners.
func startGrpcListen(cfg *Config, grpcServer *grpc.Server,
        listeners []*ListenerWithSignal) error {

        // Use a WaitGroup so we can be sure the instructions on how to input the
        // password is the last thing to be printed to the console.
        var wg sync.WaitGroup

        for _, lis := range listeners {
                wg.Add(1)
                go func(lis *ListenerWithSignal) {
                        rpcsLog.Infof("RPC server listening on %s", lis.Addr())

                        // Close the ready chan to indicate we are listening.
                        close(lis.Ready)

                        wg.Done()
                        _ = grpcServer.Serve(lis)
                }(lis)
        }

        // If Prometheus monitoring is enabled, start the Prometheus exporter.
        if cfg.Prometheus.Enabled() {
                err := monitoring.ExportPrometheusMetrics(
                        grpcServer, cfg.Prometheus,
                )
                if err != nil {
                        return err
                }
        }

        // Wait for gRPC servers to be up running.
        wg.Wait()

        return nil
}

// startRestProxy starts the given REST proxy on the listeners found in the
// config.
func startRestProxy(ctx context.Context, cfg *Config, rpcServer *rpcServer,
        restDialOpts []grpc.DialOption,
        restListen func(net.Addr) (net.Listener, error)) (func(), error) {

        // We use the first RPC listener as the destination for our REST proxy.
        // If the listener is set to listen on all interfaces, we replace it
        // with localhost, as we cannot dial it directly.
        restProxyDest := cfg.RPCListeners[0].String()
        switch {
        case strings.Contains(restProxyDest, "0.0.0.0"):
                restProxyDest = strings.Replace(
                        restProxyDest, "0.0.0.0", "127.0.0.1", 1,
                )

        case strings.Contains(restProxyDest, "[::]"):
                restProxyDest = strings.Replace(
                        restProxyDest, "[::]", "[::1]", 1,
                )
        }

        var shutdownFuncs []func()
        shutdown := func() {
                for _, shutdownFn := range shutdownFuncs {
                        shutdownFn()
                }
        }

        // Start a REST proxy for our gRPC server.
        ctx, cancel := context.WithCancel(ctx)
        shutdownFuncs = append(shutdownFuncs, cancel)

        // We'll set up a proxy that will forward REST calls to the GRPC
        // server.
        //
        // The default JSON marshaler of the REST proxy only sets OrigName to
        // true, which instructs it to use the same field names as specified in
        // the proto file and not switch to camel case. What we also want is
        // that the marshaler prints all values, even if they are falsey.
        customMarshalerOption := proxy.WithMarshalerOption(
                proxy.MIMEWildcard, &proxy.JSONPb{
                        MarshalOptions:   *lnrpc.RESTJsonMarshalOpts,
                        UnmarshalOptions: *lnrpc.RESTJsonUnmarshalOpts,
                },
        )
        mux := proxy.NewServeMux(
                customMarshalerOption,

                // Don't allow falling back to other HTTP methods, we want exact
                // matches only. The actual method to be used can be overwritten
                // by setting X-HTTP-Method-Override so there should be no
                // reason for not specifying the correct method in the first
                // place.
                proxy.WithDisablePathLengthFallback(),
        )

        // Register our services with the REST proxy.
        err := rpcServer.RegisterWithRestProxy(
                ctx, mux, restDialOpts, restProxyDest,
        )
        if err != nil {
                return nil, err
        }

        // Wrap the default grpc-gateway handler with the WebSocket handler.
        restHandler := lnrpc.NewWebSocketProxy(
                mux, rpcsLog, cfg.WSPingInterval, cfg.WSPongWait,
                lnrpc.LndClientStreamingURIs,
        )

        // Use a WaitGroup so we can be sure the instructions on how to input the
        // password is the last thing to be printed to the console.
        var wg sync.WaitGroup

        // Now spin up a network listener for each requested port and start a
        // goroutine that serves REST with the created mux there.
        for _, restEndpoint := range cfg.RESTListeners {
                lis, err := restListen(restEndpoint)
                if err != nil {
                        ltndLog.Errorf("gRPC proxy unable to listen on %s",
                                restEndpoint)
                        return nil, err
                }

                shutdownFuncs = append(shutdownFuncs, func() {
                        err := lis.Close()
                        if err != nil {
                                rpcsLog.Errorf("Error closing listener: %v",
                                        err)
                        }
                })

                wg.Add(1)
                go func() {
                        rpcsLog.Infof("gRPC proxy started at %s", lis.Addr())

                        // Create our proxy chain now. A request will pass
                        // through the following chain:
                        // req ---> CORS handler --> WS proxy --->
                        //   REST proxy --> gRPC endpoint
                        corsHandler := allowCORS(restHandler, cfg.RestCORS)

                        wg.Done()
                        err := http.Serve(lis, corsHandler)
                        if err != nil && !lnrpc.IsClosedConnError(err) {
                                rpcsLog.Error(err)
                        }
                }()
        }

        // Wait for REST servers to be up running.
        wg.Wait()

        return shutdown, nil
}

lightningnetwork / lnd / 12585581807

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