auto update clients to prevent expiry (cosmos#412)

* auto update clients to prevent expiry

* Fix lint issues

* Address PR comments

* Remove deadcode

* Address PR comments

* Address suggestions

* Modify update client code

cmd/flags.go

@@ -32,6 +32,7 @@ var (
 	flagTimeoutHeightOffset = "timeout-height-offset"
 	flagTimeoutTimeOffset   = "timeout-time-offset"
 	flagMaxRetries          = "max-retries"
+	flagThresholdTime       = "time-threshold"
 )
 
 func ibcDenomFlags(cmd *cobra.Command) *cobra.Command {
@@ -259,3 +260,11 @@ func retryFlag(cmd *cobra.Command) *cobra.Command {
 	}
 	return cmd
 }
+
+func updateTimeFlags(cmd *cobra.Command) *cobra.Command {
+	cmd.Flags().Duration(flagThresholdTime, 6*time.Hour, "time before to expiry time to update client")
+	if err := viper.BindPFlag(flagThresholdTime, cmd.Flags().Lookup(flagThresholdTime)); err != nil {
+		panic(err)
+	}
+	return cmd
+}

cmd/start.go

@@ -18,13 +18,18 @@ package cmd
 
 import (
 	"fmt"
+	"math"
 	"os"
 	"os/signal"
 	"strings"
 	"syscall"
+	"time"
 
+	retry "github.com/avast/retry-go"
 	"github.com/cosmos/relayer/relayer"
 	"github.com/spf13/cobra"
+	"github.com/spf13/viper"
+	"golang.org/x/sync/errgroup"
 )
 
 // startCmd represents the start command
@@ -70,11 +75,33 @@ $ %s start demo-path2 --max-tx-size 10`, appName, appName)),
 				return err
 			}
 
+			thresholdTime := viper.GetDuration(flagThresholdTime)
+
+			eg := new(errgroup.Group)
+			eg.Go(func() error {
+				for {
+					var timeToExpiry time.Duration
+					if err := retry.Do(func() error {
+						timeToExpiry, err = UpdateClientsFromChains(c[src], c[dst], thresholdTime)
+						if err != nil {
+							return err
+						}
+						return nil
+					}, retry.Attempts(5), retry.Delay(time.Millisecond*500), retry.LastErrorOnly(true)); err != nil {
+						return err
+					}
+					time.Sleep(timeToExpiry - thresholdTime)
+				}
+			})
+			if err = eg.Wait(); err != nil {
+				return err
+			}
+
 			trapSignal(done)
 			return nil
 		},
 	}
-	return strategyFlag(cmd)
+	return strategyFlag(updateTimeFlags(cmd))
 }
 
 // trap signal waits for a SIGINT or SIGTERM and then sends down the done channel
@@ -91,3 +118,38 @@ func trapSignal(done func()) {
 	// call the cleanup func
 	done()
 }
+
+// UpdateClientsFromChains takes src, dst chains, threshold time and update clients based on expiry time
+func UpdateClientsFromChains(src, dst *relayer.Chain, thresholdTime time.Duration) (time.Duration, error) {
+	var (
+		srcTimeExpiry, dstTimeExpiry time.Duration
+		err                          error
+	)
+
+	eg := new(errgroup.Group)
+	eg.Go(func() error {
+		srcTimeExpiry, err = relayer.AutoUpdateClient(src, dst, thresholdTime)
+		return err
+	})
+	eg.Go(func() error {
+		dstTimeExpiry, err = relayer.AutoUpdateClient(dst, src, thresholdTime)
+		return err
+	})
+	if err := eg.Wait(); err != nil {
+		return 0, err
+	}
+
+	if srcTimeExpiry <= 0 {
+		return 0, fmt.Errorf("client (%s) of chain: %s is expired",
+			src.PathEnd.ClientID, src.ChainID)
+	}
+
+	if dstTimeExpiry <= 0 {
+		return 0, fmt.Errorf("client (%s) of chain: %s is expired",
+			dst.PathEnd.ClientID, dst.ChainID)
+	}
+
+	minTimeExpiry := math.Min(float64(srcTimeExpiry), float64(dstTimeExpiry))
+
+	return time.Duration(int64(minTimeExpiry)), nil
+}

relayer/client.go

@@ -349,3 +349,92 @@ func IsMatchingClient(clientStateA, clientStateB ibctmtypes.ClientState) bool {
 func IsMatchingConsensusState(consensusStateA, consensusStateB *ibctmtypes.ConsensusState) bool {
 	return reflect.DeepEqual(*consensusStateA, *consensusStateB)
 }
+
+// AutoUpdateClient update client automatically to prevent expiry
+func AutoUpdateClient(src, dst *Chain, thresholdTime time.Duration) (time.Duration, error) {
+	height, err := src.QueryLatestHeight()
+	if err != nil {
+		return 0, err
+	}
+
+	clientStateRes, err := src.QueryClientState(height)
+	if err != nil {
+		return 0, err
+	}
+
+	// unpack any into ibc tendermint client state
+	clientStateExported, err := clienttypes.UnpackClientState(clientStateRes.ClientState)
+	if err != nil {
+		return 0, err
+	}
+
+	// cast from interface to concrete type
+	clientState, ok := clientStateExported.(*ibctmtypes.ClientState)
+	if !ok {
+		return 0, fmt.Errorf("error when casting exported clientstate with clientID %s on chain: %s",
+			src.PathEnd.ClientID, src.PathEnd.ChainID)
+	}
+
+	if clientState.TrustingPeriod <= thresholdTime {
+		return 0, fmt.Errorf("client (%s) trusting period time is less than or equal to threshold time",
+			src.PathEnd.ClientID)
+	}
+
+	// query the latest consensus state of the potential matching client
+	consensusStateResp, err := clientutils.QueryConsensusStateABCI(src.CLIContext(0),
+		src.PathEnd.ClientID, clientState.GetLatestHeight())
+	if err != nil {
+		return 0, err
+	}
+
+	exportedConsState, err := clienttypes.UnpackConsensusState(consensusStateResp.ConsensusState)
+	if err != nil {
+		return 0, err
+	}
+
+	consensusState, ok := exportedConsState.(*ibctmtypes.ConsensusState)
+	if !ok {
+		return 0, fmt.Errorf("consensus state with clientID %s from chain %s is not IBC tendermint type",
+			src.PathEnd.ClientID, src.PathEnd.ChainID)
+	}
+
+	expirationTime := consensusState.Timestamp.Add(clientState.TrustingPeriod)
+
+	timeToExpiry := time.Until(expirationTime)
+
+	if timeToExpiry > thresholdTime {
+		return timeToExpiry, nil
+	}
+
+	if clientState.IsExpired(consensusState.Timestamp, time.Now()) {
+		return 0, fmt.Errorf("client (%s) is already expired on chain: %s", src.PathEnd.ClientID, src.ChainID)
+	}
+
+	srcUpdateHeader, err := src.GetIBCUpdateHeader(dst)
+	if err != nil {
+		return 0, err
+	}
+
+	updateMsg, err := src.UpdateClient(dst)
+	if err != nil {
+		return 0, err
+	}
+
+	msgs := []sdk.Msg{updateMsg}
+
+	res, success, err := src.SendMsgs(msgs)
+	if err != nil {
+		return 0, err
+	}
+	if !success {
+		return 0, fmt.Errorf("tx failed: %s", res.RawLog)
+	}
+	src.Log(fmt.Sprintf("★ Client updated: [%s]client(%s) {%d}->{%d}",
+		src.ChainID,
+		src.PathEnd.ClientID,
+		MustGetHeight(srcUpdateHeader.TrustedHeight),
+		srcUpdateHeader.Header.Height,
+	))
+
+	return clientState.TrustingPeriod, nil
+}