Add relayer to submit header to staking contract in ethereum (ethereu…

…m#80)

* add relayer

cmd/w3qrelayer/main.go

@@ -0,0 +1,57 @@
+package main
+
+import (
+	"fmt"
+	"github.com/mitchellh/go-homedir"
+	"github.com/spf13/cobra"
+	"github.com/spf13/viper"
+	"os"
+)
+
+var cfgFile string
+
+// rootCmd represents the base command when called without any subcommands
+var rootCmd = &cobra.Command{
+	Use:   "w3qrelayer",
+	Short: "Web3q Relayer server",
+}
+
+func init() {
+	cobra.OnInitialize(initConfig)
+	//
+	rootCmd.PersistentFlags().StringVar(&cfgFile, "config", "", "config file (default is $HOME/.guardiand.yaml)")
+	rootCmd.AddCommand(RelayCmd)
+}
+
+// initConfig reads in config file and ENV variables if set.
+func initConfig() {
+	if cfgFile != "" {
+		// Use config file from the flag.
+		viper.SetConfigFile(cfgFile)
+	} else {
+		// Find home directory.
+		home, err := homedir.Dir()
+		if err != nil {
+			fmt.Println(err)
+			os.Exit(1)
+		}
+
+		// Search config in home directory with name ".relayer" (without extension).
+		viper.AddConfigPath(home)
+		viper.SetConfigName(".relayer.yaml")
+	}
+
+	viper.AutomaticEnv() // read in environment variables that match
+
+	// If a config file is found, read it in.
+	if err := viper.ReadInConfig(); err == nil {
+		fmt.Println("Using config file:", viper.ConfigFileUsed())
+	}
+}
+
+func main() {
+	if err := rootCmd.Execute(); err != nil {
+		fmt.Println(err)
+		os.Exit(1)
+	}
+}

cmd/w3qrelayer/relayer.go

@@ -0,0 +1,313 @@
+package main
+
+import (
+	"context"
+	"crypto/ecdsa"
+	"fmt"
+	"github.com/ethereum/go-ethereum"
+	"github.com/ethereum/go-ethereum/rlp"
+	"io"
+	"io/ioutil"
+	"math/big"
+	"os"
+	"strings"
+	"time"
+
+	"github.com/ethereum/go-ethereum/accounts/abi"
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/common/hexutil"
+	"github.com/ethereum/go-ethereum/core/types"
+	"github.com/ethereum/go-ethereum/crypto"
+	"github.com/ethereum/go-ethereum/ethclient"
+	"github.com/ethereum/go-ethereum/log"
+	"github.com/mattn/go-colorable"
+	"github.com/mattn/go-isatty"
+	"github.com/spf13/cobra"
+)
+
+const (
+	ABI                    = `[{"inputs":[],"name":"curEpochHeight","outputs":[{"internalType":"uint256","name":"height","type":"uint256"}],"stateMutability":"view","type":"function"},{"inputs":[],"name":"curEpochIdx","outputs":[{"internalType":"uint256","name":"","type":"uint256"}],"stateMutability":"view","type":"function"},{"inputs":[],"name":"epochPeriod","outputs":[{"internalType":"uint256","name":"height","type":"uint256"}],"stateMutability":"view","type":"function"},{"inputs":[],"name":"getCurrentEpoch","outputs":[{"internalType":"uint256","name":"","type":"uint256"},{"internalType":"address[]","name":"","type":"address[]"},{"internalType":"uint256[]","name":"","type":"uint256[]"}],"stateMutability":"view","type":"function"},{"inputs":[],"name":"getNextEpochHeight","outputs":[{"internalType":"uint256","name":"height","type":"uint256"}],"stateMutability":"view","type":"function"},{"inputs":[],"name":"getStaking","outputs":[{"internalType":"address","name":"","type":"address"}],"stateMutability":"view","type":"function"},{"inputs":[{"internalType":"address[]","name":"epochSigners","type":"address[]"},{"internalType":"uint256[]","name":"epochVotingPowers","type":"uint256[]"},{"internalType":"uint256","name":"height","type":"uint256"},{"internalType":"bytes32","name":"headHash","type":"bytes32"}],"name":"initEpoch","outputs":[],"stateMutability":"nonpayable","type":"function"},{"inputs":[],"name":"proposedValidators","outputs":[{"internalType":"address[]","name":"","type":"address[]"},{"internalType":"uint256[]","name":"","type":"uint256[]"}],"stateMutability":"view","type":"function"},{"inputs":[{"internalType":"uint256","name":"_epochPeriod","type":"uint256"}],"name":"setEpochPeriod","outputs":[],"stateMutability":"nonpayable","type":"function"},{"inputs":[{"internalType":"bytes","name":"_epochHeaderBytes","type":"bytes"},{"internalType":"bytes","name":"commitBytes","type":"bytes"},{"internalType":"bool","name":"lookByIndex","type":"bool"}],"name":"submitHead","outputs":[],"stateMutability":"nonpayable","type":"function"}]`
+	SubmitHeaderFunc       = "submitHead"
+	GetNextEpochHeightFunc = "getNextEpochHeight"
+	gas                    = uint64(1000000) // uint64(math.MaxUint64 / 2)
+	comfirmCount           = 50              // 10 * 60 / 12
+)
+
+var (
+	ethRpc      *string
+	contractStr *string
+	web3qRpc    *string
+	valKeyPath  *string
+	verbosity   *int
+	ethCli      *ethclient.Client
+	web3qCli    *ethclient.Client
+	contract    common.Address
+	rootCtx     context.Context
+)
+
+var RelayCmd = &cobra.Command{
+	Use:   "relay",
+	Short: "Run the relay server",
+	Run:   runRelay,
+}
+
+func init() {
+	ethRpc = RelayCmd.Flags().String("ethRpc", "", "rpc for relayer to submit header")
+	contractStr = RelayCmd.Flags().String("contract", "", "the contract for relayer to submit header to")
+	web3qRpc = RelayCmd.Flags().String("web3qRpc", "", "rpc for relayer to get web3q header")
+
+	valKeyPath = RelayCmd.Flags().String("valKey", "", "Path to validator key (empty if not a validator)")
+	verbosity = RelayCmd.Flags().Int("verbosity", 3, "Logging verbosity: 0=silent, 1=error, 2=warn, 3=info, 4=debug, 5=detail")
+}
+
+func runRelay(cmd *cobra.Command, args []string) {
+	glogger := log.NewGlogHandler(log.StreamHandler(os.Stderr, log.TerminalFormat(false)))
+	glogger.Verbosity(log.Lvl(*verbosity))
+	log.Root().SetHandler(glogger)
+
+	// setup logger
+	var ostream log.Handler
+	output := io.Writer(os.Stderr)
+
+	usecolor := (isatty.IsTerminal(os.Stderr.Fd()) || isatty.IsCygwinTerminal(os.Stderr.Fd())) && os.Getenv("TERM") != "dumb"
+	if usecolor {
+		output = colorable.NewColorableStderr()
+	}
+	ostream = log.StreamHandler(output, log.TerminalFormat(usecolor))
+
+	glogger.SetHandler(ostream)
+
+	// Node's main lifecycle context.
+	rootCtx, rootCtxCancel := context.WithCancel(context.Background())
+	defer rootCtxCancel()
+
+	if *ethRpc == "" {
+		log.Error("Please specify --ethRpc")
+		return
+	}
+
+	var err error
+	ethCli, err = ethclient.Dial(*ethRpc)
+	if err != nil {
+		log.Error("Failed to dial eth rpc", "err", err)
+		return
+	}
+
+	ethChainId, err := ethCli.ChainID(rootCtx)
+	if err != nil {
+		log.Error("Failed to get eth chainId", "err", err)
+		return
+	}
+
+	if *contractStr == "" {
+		log.Error("Please specify --contract")
+		return
+	}
+	contract = common.HexToAddress(*contractStr)
+
+	if *web3qRpc == "" {
+		log.Error("Please specify --web3qRpc")
+		return
+	}
+
+	web3qCli, err = ethclient.Dial(*web3qRpc)
+	if err != nil {
+		log.Error("Failed to dial web3q rpc", "err", err)
+		return
+	}
+
+	cid, err := web3qCli.ChainID(rootCtx)
+	if err != nil {
+		log.Error("Failed to dial web3q rpc", "err", err)
+		return
+	}
+	log.Info("web3q chain id", "chainid", cid)
+
+	if *valKeyPath == "" {
+		log.Error("Please specify --valKeyPath")
+		return
+	}
+
+	valKey, err := loadValidatorKey(*valKeyPath)
+	if err != nil {
+		log.Error("Failed to load validator key", "err", err)
+		return
+	}
+
+	vABI, _ := abi.JSON(strings.NewReader(ABI))
+
+	relayer := relayer{
+		ethClient:   ethCli,
+		web3qClient: web3qCli,
+		signer:      types.NewEIP2930Signer(ethChainId),
+		privKey:     valKey,
+		contract:    contract,
+		valABI:      vABI,
+		ctx:         rootCtx,
+	}
+
+	// loop
+	// 0. get eth chain current height
+	// 1. get web3q next epoch header from eth chain contract
+	// 2. get fetch epoch header from web3q chain
+	// 3. submit web3q header to eth chain if required header exist, otherwise sleep 5 minutes
+	go func() {
+		log.Info("start loop")
+		i := 0
+		for true {
+			log.Info("round", "i", i)
+			i++
+			var (
+				header          *types.Header
+				nextEpochHeight uint64
+				w3qCurNumber    uint64
+			)
+			curNumber, err := relayer.ethClient.BlockNumber(relayer.ctx)
+			if err != nil {
+				log.Error("get ethClient block number failed", "err", err.Error())
+				goto sleep
+			}
+
+			nextEpochHeight, err = relayer.GetNextEpochHeight(curNumber - comfirmCount)
+			if err != nil {
+				log.Error("GetNextEpochHeight failed", "err", err.Error())
+				goto sleep
+			}
+
+			if nextEpochHeight == 0 {
+				goto sleep
+			}
+
+			w3qCurNumber, err = relayer.web3qClient.BlockNumber(relayer.ctx)
+			if err != nil {
+				log.Error("Get block number failed", "err", err.Error())
+				goto sleep
+			}
+
+			if w3qCurNumber < nextEpochHeight {
+				goto sleep
+			}
+
+			header, err = relayer.web3qClient.HeaderByNumber(relayer.ctx, new(big.Int).SetUint64(nextEpochHeight))
+			if err != nil {
+				log.Error("FetchWeb3qHeader failed", "err", err.Error())
+				goto sleep
+			}
+
+			if header == nil {
+				goto sleep
+			}
+
+			err = relayer.SubmitHeaderToContract(header)
+			if err == nil {
+				time.Sleep(1 * time.Minute)
+				continue
+			}
+			log.Error("SubmitHeaderToContract failed", "err", err.Error())
+
+		sleep:
+			time.Sleep(5 * time.Minute)
+		}
+	}()
+
+	<-rootCtx.Done()
+}
+
+// loadValidatorKey loads a serialized guardian key from disk.
+func loadValidatorKey(filename string) (*ecdsa.PrivateKey, error) {
+	b, err := ioutil.ReadFile(filename)
+	if err != nil {
+		return nil, fmt.Errorf("failed to open file: %w", err)
+	}
+
+	gk, err := crypto.ToECDSA(b)
+	if err != nil {
+		return nil, fmt.Errorf("failed to deserialize raw key data: %w", err)
+	}
+
+	return gk, nil
+}
+
+type relayer struct {
+	ethClient   *ethclient.Client
+	web3qClient *ethclient.Client
+	signer      types.Signer
+	contract    common.Address
+	privKey     *ecdsa.PrivateKey
+	ctx         context.Context
+	valABI      abi.ABI
+}
+
+func (r *relayer) SubmitHeaderToContract(header *types.Header) error {
+	cph := types.CopyHeader(header)
+	cph.Commit = nil
+	eHeader, err := rlp.EncodeToBytes(cph)
+	if err != nil {
+		return err
+	}
+
+	eCommit, err := rlp.EncodeToBytes(header.Commit)
+	if err != nil {
+		return err
+	}
+
+	data, err := r.valABI.Pack(SubmitHeaderFunc, eHeader, eCommit, false)
+	if err != nil {
+		return err
+	}
+
+	gasPrice, err := r.ethClient.SuggestGasPrice(r.ctx)
+	if err != nil {
+		return err
+	}
+
+	nonce, err := r.ethClient.PendingNonceAt(r.ctx, crypto.PubkeyToAddress(r.privKey.PublicKey))
+	if err != nil {
+		return err
+	}
+
+	baseTx := &types.LegacyTx{
+		To:       &contract,
+		Nonce:    nonce,
+		GasPrice: gasPrice,
+		Gas:      gas,
+		Value:    new(big.Int).SetInt64(0),
+		Data:     data,
+	}
+
+	signedTx, err := types.SignTx(types.NewTx(baseTx), r.signer, r.privKey)
+	if err != nil {
+		return err
+	}
+
+	return ethCli.SendTransaction(r.ctx, signedTx)
+}
+
+func (r *relayer) GetNextEpochHeight(blockNumber uint64) (uint64, error) {
+	data, err := r.valABI.Pack(GetNextEpochHeightFunc)
+	if err != nil {
+		return 0, err
+	}
+
+	msgData := (hexutil.Bytes)(data)
+	msg := ethereum.CallMsg{
+		To:   &r.contract,
+		Gas:  gas,
+		Data: msgData,
+	}
+	result, err := r.ethClient.CallContract(r.ctx, msg, new(big.Int).SetUint64(blockNumber))
+	if err != nil {
+		return 0, err
+	}
+
+	type t struct {
+		Value *big.Int
+	}
+
+	var rh t
+	if err := r.valABI.UnpackIntoInterface(&rh, GetNextEpochHeightFunc, result); err != nil {
+		return 0, err
+	}
+
+	return rh.Value.Uint64(), nil
+}