cmd/lite: switch to new lite2 package (#4300)

* cmd/lite: switch to new lite2 package

* update changelog

* shorten the trusting period explanation

CHANGELOG_PENDING.md

@@ -17,6 +17,11 @@ information in `Block#LastCommit`. `Commit` now mainly consists of a signature
 and a validator address plus a timestamp. Note we may remove the validator
 address & timestamp fields in the future (see ADR-25).
 
+`lite2` package has been added to solve `lite` issues and introduce weak
+subjectivity interface
+https://github.com/tendermint/spec/blob/master/spec/consensus/light-client.md).
+`lite` package is now deprecated and will be removed in v0.34 release.
+
 Special thanks to external contributors on this release:
 @erikgrinaker, @PSalant726, @gchaincl, @gregzaitsev, @princesinha19, @Stumble
 
@@ -60,6 +65,9 @@ program](https://hackerone.com/tendermint).
     - You will have to generate a new config for your Tendermint node(s)
   - [genesis] \#2565 Add `consensus_params.evidence.max_age_duration`. Rename
     `consensus_params.evidence.max_age` to `max_age_num_blocks`.
+  - [cli] \#1771 `tendermint lite` now uses new light client package (`lite2`)
+    and has 3 more flags: `--trusting-period`, `--trusted-height` and
+    `--trusted-hash`
 
 - Apps
 
@@ -124,6 +132,7 @@ program](https://hackerone.com/tendermint).
   - `consensus_validator_missed_blocks`: total amount of missed blocks for a validator
   as gauges in prometheus for validator specific metrics
 - [rpc/lib] [\#4248](https://github.com/tendermint/tendermint/issues/4248) RPC client basic authentication support (@greg-szabo)
+- [lite2] \#1771 Light client with weak subjectivity
 
 ### IMPROVEMENTS:
 

cmd/tendermint/commands/lite.go

@@ -1,15 +1,23 @@
 package commands
 
 import (
-	"fmt"
-	"net/url"
+	"net/http"
+	"time"
 
 	"github.com/pkg/errors"
 	"github.com/spf13/cobra"
 
+	amino "github.com/tendermint/go-amino"
+	dbm "github.com/tendermint/tm-db"
+
 	tmos "github.com/tendermint/tendermint/libs/os"
-	"github.com/tendermint/tendermint/lite/proxy"
+	lite "github.com/tendermint/tendermint/lite2"
+	httpp "github.com/tendermint/tendermint/lite2/provider/http"
+	lproxy "github.com/tendermint/tendermint/lite2/proxy"
+	lrpc "github.com/tendermint/tendermint/lite2/rpc"
+	dbs "github.com/tendermint/tendermint/lite2/store/db"
 	rpcclient "github.com/tendermint/tendermint/rpc/client"
+	rpcserver "github.com/tendermint/tendermint/rpc/lib/server"
 )
 
 // LiteCmd represents the base command when called without any subcommands
@@ -32,7 +40,10 @@ var (
 	chainID            string
 	home               string
 	maxOpenConnections int
-	cacheSize          int
+
+	trustingPeriod time.Duration
+	trustedHeight  int64
+	trustedHash    []byte
 )
 
 func init() {
@@ -45,60 +56,59 @@ func init() {
 		"max-open-connections",
 		900,
 		"Maximum number of simultaneous connections (including WebSocket).")
-	LiteCmd.Flags().IntVar(&cacheSize, "cache-size", 10, "Specify the memory trust store cache size")
-}
 
-func EnsureAddrHasSchemeOrDefaultToTCP(addr string) (string, error) {
-	u, err := url.Parse(addr)
-	if err != nil {
-		return "", err
-	}
-	switch u.Scheme {
-	case "tcp", "unix":
-	case "":
-		u.Scheme = "tcp"
-	default:
-		return "", fmt.Errorf("unknown scheme %q, use either tcp or unix", u.Scheme)
-	}
-	return u.String(), nil
+	LiteCmd.Flags().DurationVar(&trustingPeriod, "trusting-period", 168*time.Hour, "Trusting period. Should be significantly less than the unbonding period")
+	LiteCmd.Flags().Int64Var(&trustedHeight, "trusted-height", 1, "Trusted header's height")
+	LiteCmd.Flags().BytesHexVar(&trustedHash, "trusted-hash", []byte{}, "Trusted header's hash")
 }
 
 func runProxy(cmd *cobra.Command, args []string) error {
-	// Stop upon receiving SIGTERM or CTRL-C.
-	tmos.TrapSignal(logger, func() {
-		// TODO: close up shop
-	})
-
-	nodeAddr, err := EnsureAddrHasSchemeOrDefaultToTCP(nodeAddr)
-	if err != nil {
-		return err
-	}
-	listenAddr, err := EnsureAddrHasSchemeOrDefaultToTCP(listenAddr)
-	if err != nil {
-		return err
-	}
+	liteLogger := logger.With("module", "lite")
 
+	logger.Info("Connecting to Tendermint node...")
 	// First, connect a client
-	logger.Info("Connecting to source HTTP client...")
 	node, err := rpcclient.NewHTTP(nodeAddr, "/websocket")
 	if err != nil {
 		return errors.Wrap(err, "new HTTP client")
 	}
 
-	logger.Info("Constructing Verifier...")
-	cert, err := proxy.NewVerifier(chainID, home, node, logger, cacheSize)
+	logger.Info("Creating client...")
+	db, err := dbm.NewGoLevelDB("lite-client-db", home)
 	if err != nil {
-		return errors.Wrap(err, "constructing Verifier")
+		return err
 	}
-	cert.SetLogger(logger)
-	sc := proxy.SecureClient(node, cert)
+	c, err := lite.NewClient(
+		chainID,
+		lite.TrustOptions{
+			Period: trustingPeriod,
+			Height: trustedHeight,
+			Hash:   trustedHash,
+		},
+		httpp.NewWithClient(chainID, node),
+		dbs.New(db, chainID),
+	)
+	if err != nil {
+		return err
+	}
+	c.SetLogger(liteLogger)
+
+	p := lproxy.Proxy{
+		Addr:   listenAddr,
+		Config: &rpcserver.Config{MaxOpenConnections: maxOpenConnections},
+		Codec:  amino.NewCodec(),
+		Client: lrpc.NewClient(node, c),
+		Logger: liteLogger,
+	}
+	// Stop upon receiving SIGTERM or CTRL-C.
+	tmos.TrapSignal(liteLogger, func() {
+		p.Listener.Close()
+	})
 
 	logger.Info("Starting proxy...")
-	err = proxy.StartProxy(sc, listenAddr, logger, maxOpenConnections)
-	if err != nil {
-		return errors.Wrap(err, "starting proxy")
+	if err := p.ListenAndServe(); err != http.ErrServerClosed {
+		// Error starting or closing listener:
+		logger.Error("proxy ListenAndServe", "err", err)
 	}
 
-	// Run forever
-	select {}
+	return nil
 }

lite/doc.go

@@ -1,4 +1,6 @@
 /*
+Package lite is deprecated and will be removed in v0.34!
+
 Package lite allows you to securely validate headers without a full node.
 
 This library pulls together all the crypto and algorithms, so given a

lite2/client.go

@@ -214,6 +214,8 @@ func (c *Client) restoreTrustedHeaderAndNextVals() error {
 
 		c.trustedHeader = trustedHeader
 		c.trustedNextVals = trustedNextVals
+
+		c.logger.Debug("Restored trusted header and next vals", lastHeight)
 	}
 
 	return nil
@@ -249,6 +251,10 @@ func (c *Client) checkTrustedHeaderUsingOptions(options TrustOptions) error {
 	case options.Height == c.trustedHeader.Height:
 		primaryHash = options.Hash
 	case options.Height < c.trustedHeader.Height:
+		c.logger.Info("Client initialized with old header (trusted is more recent)",
+			"old", options.Height,
+			"trusted", c.trustedHeader.Height)
+
 		action := fmt.Sprintf(
 			"Rollback to %d (%X)? Note this will remove newer headers up to %d (%X)",
 			options.Height, options.Hash,
@@ -258,6 +264,9 @@ func (c *Client) checkTrustedHeaderUsingOptions(options TrustOptions) error {
 			c.cleanup(options.Height + 1)
 			// set c.trustedHeader to one at options.Height
 			c.restoreTrustedHeaderAndNextVals()
+
+			c.logger.Info("Rolled back to older header (newer headers were removed)",
+				"old", options.Height)
 		} else {
 			return errors.New("rollback aborted")
 		}
@@ -266,8 +275,8 @@ func (c *Client) checkTrustedHeaderUsingOptions(options TrustOptions) error {
 	}
 
 	if !bytes.Equal(primaryHash, c.trustedHeader.Hash()) {
-		c.logger.Info("Prev. trusted header's hash %X doesn't match hash %X from primary provider",
-			c.trustedHeader.Hash(), primaryHash)
+		c.logger.Info("Prev. trusted header's hash (h1) doesn't match hash from primary provider (h2)",
+			"h1", c.trustedHeader.Hash(), "h1", primaryHash)
 
 		action := fmt.Sprintf(
 			"Prev. trusted header's hash %X doesn't match hash %X from primary provider. Remove all the stored headers?",
@@ -398,6 +407,8 @@ func (c *Client) ChainID() string {
 //
 // If the trusted header is more recent than one here, an error is returned.
 func (c *Client) VerifyHeaderAtHeight(height int64, now time.Time) (*types.SignedHeader, error) {
+	c.logger.Info("VerifyHeaderAtHeight", "height", height)
+
 	if c.trustedHeader.Height >= height {
 		return nil, errors.Errorf("header at more recent height #%d exists", c.trustedHeader.Height)
 	}
@@ -425,6 +436,8 @@ func (c *Client) VerifyHeaderAtHeight(height int64, now time.Time) (*types.Signe
 //
 // If the trusted header is more recent than one here, an error is returned.
 func (c *Client) VerifyHeader(newHeader *types.SignedHeader, newVals *types.ValidatorSet, now time.Time) error {
+	c.logger.Info("VerifyHeader", "height", newHeader.Hash(), "newVals", newVals.Hash())
+
 	if c.trustedHeader.Height >= newHeader.Height {
 		return errors.Errorf("header at more recent height #%d exists", c.trustedHeader.Height)
 	}
@@ -458,6 +471,7 @@ func (c *Client) VerifyHeader(newHeader *types.SignedHeader, newVals *types.Vali
 
 // Cleanup removes all the data (headers and validator sets) stored.
 func (c *Client) Cleanup() error {
+	c.logger.Info("Cleanup everything")
 	return c.cleanup(0)
 }
 
@@ -507,6 +521,11 @@ func (c *Client) sequence(newHeader *types.SignedHeader, newVals *types.Validato
 			return errors.Wrapf(err, "failed to obtain the header #%d", height)
 		}
 
+		c.logger.Debug("Verify newHeader against lastHeader",
+			"lastHeight", c.trustedHeader.Height,
+			"lastHash", c.trustedHeader.Hash(),
+			"newHeight", interimHeader.Height,
+			"newHash", interimHeader.Hash())
 		err = Verify(c.chainID, c.trustedHeader, c.trustedNextVals, interimHeader, c.trustedNextVals,
 			c.trustingPeriod, now, c.trustLevel)
 		if err != nil {
@@ -540,6 +559,11 @@ func (c *Client) bisection(
 	newVals *types.ValidatorSet,
 	now time.Time) error {
 
+	c.logger.Debug("Verify newHeader against lastHeader",
+		"lastHeight", lastHeader.Height,
+		"lastHash", lastHeader.Hash(),
+		"newHeight", newHeader.Height,
+		"newHash", newHeader.Hash())
 	err := Verify(c.chainID, lastHeader, lastVals, newHeader, newVals, c.trustingPeriod, now, c.trustLevel)
 	switch err.(type) {
 	case nil:

lite2/proxy/proxy.go

@@ -18,11 +18,12 @@ import (
 
 // A Proxy defines parameters for running an HTTP server proxy.
 type Proxy struct {
-	Addr   string // TCP address to listen on, ":http" if empty
-	Config *rpcserver.Config
-	Codec  *amino.Codec
-	Client *lrpc.Client
-	Logger log.Logger
+	Addr     string // TCP address to listen on, ":http" if empty
+	Config   *rpcserver.Config
+	Codec    *amino.Codec
+	Client   *lrpc.Client
+	Logger   log.Logger
+	Listener net.Listener
 }
 
 // ListenAndServe configures the rpcserver.WebsocketManager, sets up the RPC
@@ -34,6 +35,7 @@ func (p *Proxy) ListenAndServe() error {
 	if err != nil {
 		return err
 	}
+	p.Listener = listener
 
 	return rpcserver.StartHTTPServer(
 		listener,
@@ -51,6 +53,7 @@ func (p *Proxy) ListenAndServeTLS(certFile, keyFile string) error {
 	if err != nil {
 		return err
 	}
+	p.Listener = listener
 
 	return rpcserver.StartHTTPAndTLSServer(
 		listener,

lite2/verifier.go

@@ -19,7 +19,7 @@ var (
 // Verify verifies the new header (h2) against the old header (h1). It ensures that:
 //
 //	a) h1 can still be trusted (if not, ErrOldHeaderExpired is returned);
-//	b) h2 is valid (if not, ErrInvalidNewHeader is returned);
+//	b) h2 is valid;
 //	c) either h2.ValidatorsHash equals h1NextVals.Hash()
 //		 OR trustLevel ([1/3, 1]) of last trusted validators (h1NextVals) signed
 //		 correctly  (if not, ErrNewValSetCantBeTrusted is returned);