Adds import execution header subcommand (paritytech#691)

* Adds import execution header subcommand

* Script to import an execution header

* Tiny bit of cleanup

* Update relayer/cmd/import_execution_header.go

Co-authored-by: David Dunn <26876072+doubledup@users.noreply.github.com>

* Minor cleanup.

Co-authored-by: David Dunn <26876072+doubledup@users.noreply.github.com>

relayer/cmd/import_execution_header.go

@@ -0,0 +1,118 @@
+package cmd
+
+import (
+	"fmt"
+	"io/ioutil"
+	"strings"
+
+	"github.com/ethereum/go-ethereum/common"
+	log "github.com/sirupsen/logrus"
+	"github.com/snowfork/snowbridge/relayer/chain/parachain"
+	"github.com/snowfork/snowbridge/relayer/crypto/sr25519"
+	"github.com/snowfork/snowbridge/relayer/relays/beacon/header/syncer"
+	"github.com/snowfork/snowbridge/relayer/relays/beacon/writer"
+	"github.com/spf13/cobra"
+	"golang.org/x/sync/errgroup"
+)
+
+func importExecutionHeaderCmd() *cobra.Command {
+	cmd := &cobra.Command{
+		Use:   "import-execution-header",
+		Short: "Import the provided execution header.",
+		Args:  cobra.ExactArgs(0),
+		RunE:  importExecutionHeaderFn,
+	}
+
+	cmd.Flags().String("beacon-header", "", "Beacon header hash whose execution header will be imported")
+	cmd.MarkFlagRequired("beacon-header")
+
+	cmd.Flags().String("parachain-endpoint", "", "Parachain API URL")
+	cmd.MarkFlagRequired("parachain-endpoint")
+
+	cmd.Flags().String("lodestar-endpoint", "", "Lodestar API URL")
+	cmd.MarkFlagRequired("lodestar-endpoint")
+
+	cmd.Flags().String("private-key-file", "", "File containing the private key for the relayer")
+	cmd.MarkFlagRequired("private-key-file")
+
+	return cmd
+}
+
+func importExecutionHeaderFn(cmd *cobra.Command, _ []string) error {
+
+	err := func() error {
+		ctx := cmd.Context()
+
+		eg, ctx := errgroup.WithContext(ctx)
+
+		parachainEndpoint, _ := cmd.Flags().GetString("parachain-endpoint")
+		privateKeyFile, _ := cmd.Flags().GetString("private-key-file")
+		lodestarEndpoint, _ := cmd.Flags().GetString("lodestar-endpoint")
+		beaconHeader, _ := cmd.Flags().GetString("beacon-header")
+
+		keypair, err := getKeyPair(privateKeyFile)
+		if err != nil {
+			return fmt.Errorf("get keypair from file: %w", err)
+		}
+
+		paraconn := parachain.NewConnection(parachainEndpoint, keypair.AsKeyringPair())
+		err = paraconn.Connect(ctx)
+		if err != nil {
+			return fmt.Errorf("connect to parachain: %w", err)
+		}
+
+		writer := writer.NewParachainWriter(paraconn, 32)
+		err = writer.Start(ctx, eg)
+		if err != nil {
+			return fmt.Errorf("start parachain conn: %w", err)
+		}
+
+		log.WithField("hash", beaconHeader).Info("will be syncing execution header for beacon hash")
+
+		syncer := syncer.New(lodestarEndpoint, 32, 256)
+
+		beaconHeaderHash := common.HexToHash(beaconHeader)
+
+		update, err := syncer.GetHeaderUpdate(beaconHeaderHash)
+		if err != nil {
+			return fmt.Errorf("get header update: %w", err)
+		}
+		log.WithField("slot", update.Block.Slot).Info("found block at slot")
+
+		syncAggregate, err := syncer.GetSyncAggregateForSlot(uint64(update.Block.Slot) + 1)
+		if err != nil {
+			return fmt.Errorf("get sync aggregate: %w", err)
+		}
+		log.Info("found sync aggregate")
+
+		update.SyncAggregate = syncAggregate
+
+		err = writer.WriteToParachainAndWatch(ctx, "EthereumBeaconClient.import_execution_header", update)
+		if err != nil {
+			return fmt.Errorf("write to parachain: %w", err)
+		}
+		log.Info("imported execution header")
+
+		return nil
+	}()
+	if err != nil {
+		log.WithError(err).Error("error importing execution header")
+	}
+
+	return nil
+}
+
+func getKeyPair(privateKeyFile string) (*sr25519.Keypair, error) {
+	var cleanedKeyURI string
+	content, err := ioutil.ReadFile(privateKeyFile)
+	if err != nil {
+		return nil, fmt.Errorf("cannot read key file: %w", err)
+	}
+	cleanedKeyURI = strings.TrimSpace(string(content))
+	keypair, err := sr25519.NewKeypairFromSeed(cleanedKeyURI, 42)
+	if err != nil {
+		return nil, fmt.Errorf("parse private key URI: %w", err)
+	}
+
+	return keypair, nil
+}

relayer/cmd/root.go

@@ -27,6 +27,7 @@ func init() {
 	rootCmd.AddCommand(leafCmd())
 	rootCmd.AddCommand(basicChannelLeafProofCmd())
 	rootCmd.AddCommand(parachainHeadProofCmd())
+	rootCmd.AddCommand(importExecutionHeaderCmd())
 }
 
 func Execute() {