feat(rpc): keep retrying when connecting to endpoints

pkg/rpc/client.go

@@ -4,7 +4,9 @@ import (
 	"context"
 	"time"
 
+	"github.com/cenkalti/backoff/v4"
 	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/log"
 	"github.com/taikoxyz/taiko-client/bindings"
 )
 
@@ -48,19 +50,52 @@ type ClientConfig struct {
 
 // NewClient initializes all RPC clients used by Taiko client software.
 func NewClient(ctx context.Context, cfg *ClientConfig) (*Client, error) {
-	ctxWithTimeout, cancel := ctxWithTimeoutOrDefault(ctx, defaultTimeout)
-	defer cancel()
+	var (
+		l1Client       *EthClient
+		l2Client       *EthClient
+		l1BeaconClient *BeaconClient
+		l2CheckPoint   *EthClient
+		err            error
+	)
 
-	l1Client, err := NewEthClient(ctxWithTimeout, cfg.L1Endpoint, cfg.Timeout)
-	if err != nil {
-		return nil, err
-	}
+	// Keep retrying to connect to the RPC endpoints until success or context is cancelled.
+	if err := backoff.Retry(func() error {
+		ctxWithTimeout, cancel := ctxWithTimeoutOrDefault(ctx, defaultTimeout)
+		defer cancel()
 
-	l2Client, err := NewEthClient(ctxWithTimeout, cfg.L2Endpoint, cfg.Timeout)
-	if err != nil {
+		if l1Client, err = NewEthClient(ctxWithTimeout, cfg.L1Endpoint, cfg.Timeout); err != nil {
+			log.Error("Failed to connect to L1 endpoint, retrying", "endpoint", cfg.L1Endpoint, "err", err)
+			return err
+		}
+
+		if l2Client, err = NewEthClient(ctxWithTimeout, cfg.L2Endpoint, cfg.Timeout); err != nil {
+			log.Error("Failed to connect to L2 endpoint, retrying", "endpoint", cfg.L2Endpoint, "err", err)
+			return err
+		}
+
+		if cfg.L1BeaconEndpoint != "" {
+			if l1BeaconClient, err = NewBeaconClient(cfg.L1BeaconEndpoint, defaultTimeout); err != nil {
+				log.Error("Failed to connect to L1 beacon endpoint, retrying", "endpoint", cfg.L1BeaconEndpoint, "err", err)
+				return err
+			}
+		}
+
+		if cfg.L2CheckPoint != "" {
+			l2CheckPoint, err = NewEthClient(ctxWithTimeout, cfg.L2CheckPoint, cfg.Timeout)
+			if err != nil {
+				log.Error("Failed to connect to L2 checkpoint endpoint, retrying", "endpoint", cfg.L2CheckPoint, "err", err)
+				return err
+			}
+		}
+
+		return nil
+	}, backoff.WithContext(backoff.NewExponentialBackOff(), ctx)); err != nil {
 		return nil, err
 	}
 
+	ctxWithTimeout, cancel := ctxWithTimeoutOrDefault(ctx, defaultTimeout)
+	defer cancel()
+
 	taikoL1, err := bindings.NewTaikoL1Client(cfg.TaikoL1Address, l1Client)
 	if err != nil {
 		return nil, err
@@ -96,21 +131,6 @@ func NewClient(ctx context.Context, cfg *ClientConfig) (*Client, error) {
 		}
 	}
 
-	var l1BeaconClient *BeaconClient
-	if cfg.L1BeaconEndpoint != "" {
-		if l1BeaconClient, err = NewBeaconClient(cfg.L1BeaconEndpoint, defaultTimeout); err != nil {
-			return nil, err
-		}
-	}
-
-	var l2CheckPoint *EthClient
-	if cfg.L2CheckPoint != "" {
-		l2CheckPoint, err = NewEthClient(ctxWithTimeout, cfg.L2CheckPoint, cfg.Timeout)
-		if err != nil {
-			return nil, err
-		}
-	}
-
 	client := &Client{
 		L1:             l1Client,
 		L1Beacon:       l1BeaconClient,