add withdraw fee payer funds

proto/band/tunnel/v1beta1/tx.proto

@@ -26,6 +26,9 @@ service Msg {
   // UpdateSignalsAndInterval is a RPC method to update a signals and interval of the tunnel.
   rpc UpdateSignalsAndInterval(MsgUpdateSignalsAndInterval) returns (MsgUpdateSignalsAndIntervalResponse);
 
+  // WithdrawFeePayerFunds is a RPC method to withdraw fee payer funds to creator.
+  rpc WithdrawFeePayerFunds(MsgWithdrawFeePayerFunds) returns (MsgWithdrawFeePayerFundsResponse);
+
   // Activate is a RPC method to activate a tunnel.
   rpc Activate(MsgActivate) returns (MsgActivateResponse);
 
@@ -105,6 +108,26 @@ message MsgUpdateSignalsAndInterval {
 // MsgUpdateSignalsAndIntervalResponse is the response type for the Msg/UpdateSignalsAndInterval RPC method.
 message MsgUpdateSignalsAndIntervalResponse {}
 
+// MsgWithdrawFeePayerFunds is the transaction message to withdraw fee payer funds to creator.
+message MsgWithdrawFeePayerFunds {
+  option (cosmos.msg.v1.signer) = "fee_payer";
+  option (amino.name)           = "tunnel/MsgWithdrawFeePayerCoins";
+
+  // tunnel_id is the ID of the tunnel to withdraw fee payer coins.
+  uint64 tunnel_id = 1 [(gogoproto.customname) = "TunnelID"];
+  // coins is the coins to withdraw.
+  repeated cosmos.base.v1beta1.Coin amount = 2 [
+    (gogoproto.nullable)     = false,
+    (gogoproto.castrepeated) = "github.com/cosmos/cosmos-sdk/types.Coins",
+    (amino.dont_omitempty)   = true
+  ];
+  // creator is the address of the creator.
+  string creator = 3 [(cosmos_proto.scalar) = "cosmos.AddressString"];
+}
+
+// MsgWithdrawFeePayerFundsResponse is the response type for the Msg/WithdrawFeePayerFunds RPC method.
+message MsgWithdrawFeePayerFundsResponse {}
+
 // Activate is the transaction message to activate a tunnel.
 message MsgActivate {
   option (cosmos.msg.v1.signer) = "creator";

x/tunnel/client/cli/tx.go

@@ -28,6 +28,7 @@ func GetTxCmd() *cobra.Command {
 		GetTxCmdCreateTunnel(),
 		GetTxCmdUpdateRoute(),
 		GetTxCmdUpdateSignalsAndInterval(),
+		GetTxCmdWithdrawFeePayerFunds(),
 		GetTxCmdActivate(),
 		GetTxCmdDeactivate(),
 		GetTxCmdTriggerTunnel(),
@@ -246,6 +247,37 @@ func GetTxCmdUpdateSignalsAndInterval() *cobra.Command {
 	return cmd
 }
 
+func GetTxCmdWithdrawFeePayerFunds() *cobra.Command {
+	cmd := &cobra.Command{
+		Use:   "withdraw-fee-payer-funds [tunnel-id] [amount]",
+		Short: "Withdraw fee payer funds from a tunnel to the creator",
+		Args:  cobra.ExactArgs(2),
+		RunE: func(cmd *cobra.Command, args []string) error {
+			clientCtx, err := client.GetClientTxContext(cmd)
+			if err != nil {
+				return err
+			}
+
+			id, err := strconv.ParseUint(args[0], 10, 64)
+			if err != nil {
+				return err
+			}
+
+			amount, err := sdk.ParseCoinsNormalized(args[1])
+			if err != nil {
+				return err
+			}
+
+			msg := types.NewMsgWithdrawFeePayerFunds(id, amount, clientCtx.GetFromAddress().String())
+			return tx.GenerateOrBroadcastTxCLI(clientCtx, cmd.Flags(), msg)
+		},
+	}
+
+	flags.AddTxFlagsToCmd(cmd)
+
+	return cmd
+}
+
 func GetTxCmdActivate() *cobra.Command {
 	cmd := &cobra.Command{
 		Use:   "activate [tunnel-id]",

x/tunnel/keeper/msg_server.go

@@ -170,6 +170,35 @@ func (k msgServer) UpdateSignalsAndInterval(
 	return &types.MsgUpdateSignalsAndIntervalResponse{}, nil
 }
 
+// WithdrawFeePayerFunds withdraws the fee payer's funds from the tunnel to the creator.
+func (k msgServer) WithdrawFeePayerFunds(
+	goCtx context.Context,
+	msg *types.MsgWithdrawFeePayerFunds,
+) (*types.MsgWithdrawFeePayerFundsResponse, error) {
+	ctx := sdk.UnwrapSDKContext(goCtx)
+
+	tunnel, err := k.Keeper.GetTunnel(ctx, msg.TunnelID)
+	if err != nil {
+		return nil, err
+	}
+
+	if msg.Creator != tunnel.Creator {
+		return nil, types.ErrInvalidTunnelCreator.Wrapf("creator %s, tunnelID %d", msg.Creator, msg.TunnelID)
+	}
+
+	// send coins from the fee payer to the creator
+	if err := k.Keeper.bankKeeper.SendCoins(
+		ctx,
+		sdk.AccAddress(tunnel.FeePayer),
+		sdk.AccAddress(tunnel.Creator),
+		msg.Amount,
+	); err != nil {
+		return nil, err
+	}
+
+	return &types.MsgWithdrawFeePayerFundsResponse{}, nil
+}
+
 // Activate activates a tunnel.
 func (k msgServer) Activate(
 	goCtx context.Context,

x/tunnel/types/expected_keepers.go

@@ -26,9 +26,9 @@ type AccountKeeper interface {
 }
 
 type BankKeeper interface {
+	SendCoins(ctx context.Context, fromAddr sdk.AccAddress, toAddr sdk.AccAddress, amt sdk.Coins) error
 	GetAllBalances(ctx context.Context, addr sdk.AccAddress) sdk.Coins
 	SpendableCoins(ctx context.Context, addr sdk.AccAddress) sdk.Coins
-
 	SendCoinsFromModuleToAccount(
 		ctx context.Context,
 		senderModule string,

x/tunnel/types/msgs.go

@@ -11,9 +11,9 @@ import (
 )
 
 var (
-	_, _, _, _, _, _, _, _, _ sdk.Msg                       = &MsgCreateTunnel{}, &MsgUpdateRoute{}, &MsgUpdateSignalsAndInterval{}, &MsgActivate{}, &MsgDeactivate{}, &MsgTriggerTunnel{}, &MsgDepositToTunnel{}, &MsgWithdrawFromTunnel{}, &MsgUpdateParams{}
-	_, _, _, _, _, _, _, _, _ sdk.HasValidateBasic          = &MsgCreateTunnel{}, &MsgUpdateRoute{}, &MsgUpdateSignalsAndInterval{}, &MsgActivate{}, &MsgDeactivate{}, &MsgTriggerTunnel{}, &MsgDepositToTunnel{}, &MsgWithdrawFromTunnel{}, &MsgUpdateParams{}
-	_, _                      types.UnpackInterfacesMessage = &MsgCreateTunnel{}, &MsgUpdateRoute{}
+	_, _, _, _, _, _, _, _, _, _ sdk.Msg                       = &MsgCreateTunnel{}, &MsgUpdateRoute{}, &MsgUpdateSignalsAndInterval{}, &MsgWithdrawFeePayerFunds{}, &MsgActivate{}, &MsgDeactivate{}, &MsgTriggerTunnel{}, &MsgDepositToTunnel{}, &MsgWithdrawFromTunnel{}, &MsgUpdateParams{}
+	_, _, _, _, _, _, _, _, _    sdk.HasValidateBasic          = &MsgCreateTunnel{}, &MsgUpdateRoute{}, &MsgUpdateSignalsAndInterval{}, &MsgActivate{}, &MsgDeactivate{}, &MsgTriggerTunnel{}, &MsgDepositToTunnel{}, &MsgWithdrawFromTunnel{}, &MsgUpdateParams{}
+	_, _                         types.UnpackInterfacesMessage = &MsgCreateTunnel{}, &MsgUpdateRoute{}
 )
 
 // NewMsgCreateTunnel creates a new MsgCreateTunnel instance.
@@ -228,6 +228,30 @@ func (m MsgUpdateSignalsAndInterval) ValidateBasic() error {
 	return nil
 }
 
+// NewMsgWithdrawFeePayerFunds creates a new MsgWithdrawFeePayerFunds instance.
+func NewMsgWithdrawFeePayerFunds(tunnelID uint64, amount sdk.Coins, creator string) *MsgWithdrawFeePayerFunds {
+	return &MsgWithdrawFeePayerFunds{
+		TunnelID: tunnelID,
+		Amount:   amount,
+		Creator:  creator,
+	}
+}
+
+// ValidateBasic does a sanity check on the provided data
+func (m MsgWithdrawFeePayerFunds) ValidateBasic() error {
+	// creator address must be valid
+	if _, err := sdk.AccAddressFromBech32(m.Creator); err != nil {
+		return sdkerrors.ErrInvalidAddress.Wrapf("invalid address: %s", err)
+	}
+
+	// amount must be valid
+	if !m.Amount.IsValid() {
+		return sdkerrors.ErrInvalidCoins.Wrapf("invalid funds: %s", m.Amount)
+	}
+
+	return nil
+}
+
 // NewMsgActivate creates a new MsgActivate instance.
 func NewMsgActivate(
 	tunnelID uint64,