relayer: helper for txn listening

relayer.go

@@ -41,6 +41,10 @@ type Relayer interface {
 
 type MetaTxnID string
 
+func (id MetaTxnID) String() string {
+	return string(id)
+}
+
 type MetaTxnStatus uint8
 
 const (

relayer/proto/relayer.go

@@ -3,6 +3,8 @@ package proto
 import (
 	"fmt"
 	"net/http"
+
+	"github.com/0xsequence/go-sequence"
 )
 
 type Options struct {
@@ -45,3 +47,27 @@ func (c *httpclient) Do(req *http.Request) (*http.Response, error) {
 	}
 	return c.client.Do(req)
 }
+
+func MetaTxnStatusFromString(s string) sequence.MetaTxnStatus {
+	var ethTxnStatus ETHTxnStatus
+	ethTxnStatus.UnmarshalJSON([]byte(s))
+
+	switch ethTxnStatus {
+	case ETHTxnStatus_UNKNOWN:
+		return sequence.MetaTxnStatusUnknown
+	case ETHTxnStatus_DROPPED:
+		return sequence.MetaTxnStatusUnknown
+	case ETHTxnStatus_QUEUED:
+		return sequence.MetaTxnStatusUnknown
+	case ETHTxnStatus_SENT:
+		return sequence.MetaTxnStatusUnknown
+	case ETHTxnStatus_SUCCEEDED:
+		return sequence.MetaTxnExecuted
+	case ETHTxnStatus_PARTIALLY_FAILED:
+		return sequence.MetaTxnFailed
+	case ETHTxnStatus_FAILED:
+		return sequence.MetaTxnFailed
+	default:
+		return sequence.MetaTxnStatusUnknown
+	}
+}

relayer/rpc_relayer.go

@@ -2,6 +2,7 @@ package relayer
 
 import (
 	"context"
+	"encoding/json"
 	"fmt"
 	"math/big"
 	"net/url"
@@ -167,13 +168,12 @@ func (r *RpcRelayer) Relay(ctx context.Context, signedTxs *sequence.SignedTransa
 
 // ....
 func (r *RpcRelayer) Wait(ctx context.Context, metaTxnID sequence.MetaTxnID, optTimeout ...time.Duration) (sequence.MetaTxnStatus, *types.Receipt, error) {
+	// Fetch the meta transaction receipt from the relayer service
 	if r.receiptListener == nil {
-		return 0, nil, fmt.Errorf("relayer: failed to wait for metaTxnID as receiptListener is not set")
+		return r.waitMetaTxnReceipt(ctx, metaTxnID, optTimeout...)
 	}
 
-	// TODO: call rpcRelayer host RPC method GetMetaTxnReceipt()
-	// which in the future will be renamed to WaitTransactionReceipt()
-
+	// Fetch the meta transaction receipt from the receipt listener
 	result, receipt, _, err := sequence.FetchMetaTransactionReceipt(ctx, r.receiptListener, metaTxnID, optTimeout...)
 	if err != nil {
 		return 0, nil, err
@@ -185,6 +185,46 @@ func (r *RpcRelayer) Wait(ctx context.Context, metaTxnID sequence.MetaTxnID, opt
 	return status, receipt.Receipt(), nil
 }
 
+func (r *RpcRelayer) waitMetaTxnReceipt(ctx context.Context, metaTxnID sequence.MetaTxnID, optTimeout ...time.Duration) (sequence.MetaTxnStatus, *types.Receipt, error) {
+	// TODO: in future GetMetaTxnReceipt() will be renamed to WaitTransactionReceipt()
+
+	var clear context.CancelFunc
+	if len(optTimeout) > 0 {
+		ctx, clear = context.WithTimeout(ctx, optTimeout[0])
+		defer clear()
+	}
+
+	for {
+		select {
+		case <-ctx.Done():
+			err := ctx.Err()
+			if err != nil {
+				return 0, nil, err
+			}
+			return 0, nil, nil
+		default:
+		}
+
+		metaTxnReceipt, err := r.Service.GetMetaTxnReceipt(ctx, metaTxnID.String())
+		if metaTxnReceipt == nil && err == nil {
+			// currently we assume that if the receipt is nil, and error is nil, then
+			// we're still searching for the transaction. This is a hack, and we should
+			// use proper error codes when we upgrade webrpc version
+			continue
+		}
+		if err != nil {
+			return sequence.MetaTxnStatusUnknown, nil, err
+		}
+		txnReceipt := metaTxnReceipt.TxnReceipt
+		var receipt *types.Receipt
+		err = json.Unmarshal([]byte(txnReceipt), &receipt)
+		if err != nil {
+			return 0, nil, fmt.Errorf("failed to decode txn receipt data: %w", err)
+		}
+		return proto.MetaTxnStatusFromString(metaTxnReceipt.Status), receipt, nil
+	}
+}
+
 func (r *RpcRelayer) protoConfig(ctx context.Context, config core.WalletConfig, walletAddress common.Address) (*proto.WalletConfig, error) {
 	if walletConfigV1 := config.(*v1.WalletConfig); walletConfigV1 != nil {
 		var signers []*proto.WalletSigner