feat(sequencer): add fee denom to sequencer metadata (#1662)

app/upgrades/v4/upgrade.go

@@ -407,6 +407,7 @@ func ConvertOldSequencerToNew(old sequencertypes.Sequencer) sequencertypes.Seque
 			ExtraData: nil,
 			Snapshots: []*sequencertypes.SnapshotInfo{},
 			GasPrice:  &defaultGasPrice,
+			FeeDenom:  nil,
 		},
 	}
 }

proto/dymensionxyz/dymension/sequencer/metadata.proto

@@ -33,6 +33,8 @@ message SequencerMetadata {
   repeated SnapshotInfo snapshots = 14;
   // gas_price defines the value for each gas unit
   string gas_price = 15 [(gogoproto.customtype) = "github.com/cosmos/cosmos-sdk/types.Int"];
+  // fee_denom is the base denom for fees
+  DenomMetadata fee_denom = 16;
 }
 
 message ContactDetails {
@@ -52,3 +54,9 @@ message SnapshotInfo {
   // sha-256 checksum value for the snapshot file
   string checksum=3;
 }
+
+message DenomMetadata {
+  string display = 1;
+  string base = 2;
+  uint32 exponent = 3;
+}

x/sequencer/types/errors.go

@@ -24,4 +24,5 @@ var (
 	ErrInvalidAddr               = gerrc.ErrInvalidArgument.Wrap("address")
 	ErrInvalidPubKey             = gerrc.ErrInvalidArgument.Wrap("pubkey")
 	ErrUnknownRequest            = gerrc.ErrInvalidArgument.Wrap("unknown request")
+	ErrInvalidFeeDenom           = gerrc.ErrInvalidArgument.Wrap("invalid fee denom")
 )

x/sequencer/types/metadata.go

@@ -6,6 +6,7 @@ import (
 
 	errorsmod "cosmossdk.io/errors"
 	"github.com/cockroachdb/errors"
+	sdk "github.com/cosmos/cosmos-sdk/types"
 	"github.com/dymensionxyz/gerr-cosmos/gerrc"
 )
 
@@ -19,6 +20,12 @@ const (
 	maxListLength         = 5
 )
 
+type AllowedDecimals uint32
+
+const (
+	Decimals18 AllowedDecimals = 18
+)
+
 func (d SequencerMetadata) Validate() error {
 	_, err := d.EnsureLength()
 	if err != nil {
@@ -33,13 +40,40 @@ func (d SequencerMetadata) Validate() error {
 		return errorsmod.Wrap(err, "invalid rest api URLs")
 	}
 
+	if d.FeeDenom != nil {
+		if err := d.FeeDenom.Validate(); err != nil {
+			return errors.Join(ErrInvalidFeeDenom, err)
+		}
+	}
+
 	if d.ContactDetails == nil {
 		return nil
 	}
 
 	return d.ContactDetails.Validate()
 }
 
+func (dm DenomMetadata) IsSet() bool {
+	return dm != DenomMetadata{}
+}
+
+func (dm DenomMetadata) Validate() error {
+	if err := sdk.ValidateDenom(dm.Base); err != nil {
+		return fmt.Errorf("invalid metadata base denom: %w", err)
+	}
+
+	if err := sdk.ValidateDenom(dm.Display); err != nil {
+		return fmt.Errorf("invalid metadata display denom: %w", err)
+	}
+
+	// validate exponent
+	if AllowedDecimals(dm.Exponent) != Decimals18 {
+		return fmt.Errorf("invalid exponent")
+	}
+
+	return nil
+}
+
 func (cd ContactDetails) Validate() error {
 	if cd.Website != "" {
 		if err := validateURL(cd.Website); err != nil {