Add --period to "synccommittee members".

CHANGELOG.md

@@ -1,3 +1,6 @@
+development:
+  - add --period to "synccommittee members", can be "current", "next"
+
 1.14.0:
   - add "chain verify signedcontributionandproof"
   - show both block and body root in "block info"

cmd/synccommittee/members/input.go

@@ -18,7 +18,6 @@ import (
 	"time"
 
 	eth2client "github.com/attestantio/go-eth2-client"
-	spec "github.com/attestantio/go-eth2-client/spec/phase0"
 	"github.com/pkg/errors"
 	"github.com/spf13/viper"
 	"github.com/wealdtech/ethdo/services/chaintime"
@@ -35,7 +34,8 @@ type dataIn struct {
 	// Operation.
 	eth2Client eth2client.Service
 	chainTime  chaintime.Service
-	epoch      spec.Epoch
+	epoch      int64
+	period     string
 }
 
 func input(ctx context.Context) (*dataIn, error) {
@@ -67,12 +67,8 @@ func input(ctx context.Context) (*dataIn, error) {
 	}
 
 	// Epoch
-	epoch := viper.GetInt64("epoch")
-	if epoch == -1 {
-		data.epoch = data.chainTime.CurrentEpoch()
-	} else {
-		data.epoch = spec.Epoch(epoch)
-	}
+	data.epoch = viper.GetInt64("epoch")
+	data.period = viper.GetString("period")
 
 	return data, nil
 }

cmd/synccommittee/members/process.go

@@ -16,8 +16,10 @@ package members
 import (
 	"context"
 	"fmt"
+	"strings"
 
 	eth2client "github.com/attestantio/go-eth2-client"
+	"github.com/attestantio/go-eth2-client/spec/phase0"
 	"github.com/pkg/errors"
 )
 
@@ -26,11 +28,12 @@ func process(ctx context.Context, data *dataIn) (*dataOut, error) {
 		return nil, errors.New("no data")
 	}
 
-	if data.epoch < data.chainTime.AltairInitialEpoch() {
-		return nil, errors.New("not an Altair epoch")
+	epoch, err := calculateEpoch(ctx, data)
+	if err != nil {
+		return nil, err
 	}
 
-	syncCommittee, err := data.eth2Client.(eth2client.SyncCommitteesProvider).SyncCommittee(ctx, fmt.Sprintf("%d", data.chainTime.FirstSlotOfEpoch(data.epoch)))
+	syncCommittee, err := data.eth2Client.(eth2client.SyncCommitteesProvider).SyncCommittee(ctx, fmt.Sprintf("%d", data.chainTime.FirstSlotOfEpoch(epoch)))
 	if err != nil {
 		return nil, errors.Wrap(err, "failed to obtain sync committee information")
 	}
@@ -48,3 +51,27 @@ func process(ctx context.Context, data *dataIn) (*dataOut, error) {
 
 	return results, nil
 }
+
+func calculateEpoch(ctx context.Context, data *dataIn) (phase0.Epoch, error) {
+	var epoch phase0.Epoch
+	if data.epoch != -1 {
+		epoch = phase0.Epoch(data.epoch)
+	} else {
+		switch strings.ToLower(data.period) {
+		case "", "current":
+			epoch = data.chainTime.CurrentEpoch()
+		case "next":
+			period := data.chainTime.SlotToSyncCommitteePeriod(data.chainTime.CurrentSlot())
+			nextPeriod := period + 1
+			epoch = data.chainTime.FirstEpochOfSyncPeriod(nextPeriod)
+		default:
+			return 0, fmt.Errorf("period %s not known", data.period)
+		}
+	}
+
+	if data.debug {
+		fmt.Printf("epoch is %d\n", epoch)
+	}
+
+	return epoch, nil
+}

cmd/synccommitteemembers.go

@@ -28,7 +28,9 @@ var synccommitteeMembersCmd = &cobra.Command{
 
     ethdo synccommittee members --epoch=12345
 
-In quiet mode this will return 0 if the synccommittee members are found, otherwise 1.`,
+In quiet mode this will return 0 if the synccommittee members are found, otherwise 1.
+
+epoch can be a specific epoch.  period can be 'current' for the current sync period or 'next' for the next sync period`,
 	RunE: func(cmd *cobra.Command, args []string) error {
 		res, err := synccommitteemembers.Run(cmd)
 		if err != nil {
@@ -48,10 +50,14 @@ func init() {
 	synccommitteeCmd.AddCommand(synccommitteeMembersCmd)
 	synccommitteeFlags(synccommitteeMembersCmd)
 	synccommitteeMembersCmd.Flags().Int64("epoch", -1, "the epoch for which to fetch sync committees")
+	synccommitteeMembersCmd.Flags().String("period", "", "the sync committee period for which to fetch sync committees ('current', 'next')")
 }
 
 func synccommitteeMembersBindings() {
 	if err := viper.BindPFlag("epoch", synccommitteeMembersCmd.Flags().Lookup("epoch")); err != nil {
 		panic(err)
 	}
+	if err := viper.BindPFlag("period", synccommitteeMembersCmd.Flags().Lookup("period")); err != nil {
+		panic(err)
+	}
 }