refac: Update RPC client creation

Updates:
- Strengthen client validation
- Allow providing a list of RPC endpoints

internal/lido/contracts/contract_setup.go → internal/lido/contracts/client.go

@@ -16,7 +16,9 @@ limitations under the License.
 package contracts
 
 import (
+	"context"
 	"fmt"
+	"math/big"
 
 	"github.com/NethermindEth/sedge/configs"
 	"github.com/ethereum/go-ethereum/ethclient"
@@ -36,17 +38,39 @@ func connectToRPCETH(RPCs []string) (*ethclient.Client, error) {
 	return nil, fmt.Errorf("failed to connect to any RPC URL")
 }
 
-func ConnectClient(network string) (*ethclient.Client, error) {
-	rpcs, err := configs.GetPublicRPCs(network)
-	if err != nil {
-		return nil, fmt.Errorf("failed to get public RPC: %w", err)
+func ConnectClient(network string, RPCs ...string) (*ethclient.Client, error) {
+	var rpcs []string
+	var err error
+
+	if len(RPCs) == 0 {
+		rpcs, err = configs.GetPublicRPCs(network)
+		if err != nil {
+			return nil, fmt.Errorf("failed to get public RPC: %w", err)
+		}
+	} else {
+		rpcs = RPCs
 	}
 
-	// Connect to the RPC endpoint
 	client, err := connectToRPCETH(rpcs)
 	if err != nil {
 		return nil, fmt.Errorf("failed to connect to RPC: %w", err)
 	}
 
-	return client, nil
+	// Verify that the client is indeed an Ethereum RPC client
+	if client != nil {
+		// Try to get the chain ID, which is a basic operation that should work for any Ethereum client
+		chainID, err := client.ChainID(context.Background())
+		if err == nil {
+			expectedChainID := configs.NetworksConfigs()[network].ChainID
+			if chainID.Cmp(new(big.Int).SetUint64(expectedChainID)) == 0 {
+				// If we successfully got the chain ID and it matches the expected one,
+				// we can be reasonably sure this is the correct Ethereum client
+				return client, nil
+			}
+		}
+		// If there was an error or chain ID mismatch, close the client and continue to the next URL
+		client.Close()
+	}
+
+	return nil, fmt.Errorf("failed to connect to RPC: %w", err)
 }

internal/lido/contracts/client_test.go

@@ -0,0 +1,102 @@
+/*
+Copyright 2022 Nethermind
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+	http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+package contracts
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestConnectClient(t *testing.T) {
+	tcs := []struct {
+		name    string
+		network string
+		wantErr bool
+	}{
+		{
+			name:    "ConnectClient, Holesky",
+			network: "holesky",
+			wantErr: false,
+		},
+		{
+			name:    "ConnectClient, invalid Network",
+			network: "invalid",
+			wantErr: true,
+		},
+		{
+			name:    "ConnectClient, Mainnet",
+			network: "mainnet",
+			wantErr: false,
+		},
+	}
+	for _, tc := range tcs {
+		t.Run(tc.name, func(t *testing.T) {
+			client, err := ConnectClient(tc.network)
+			if tc.wantErr {
+				require.Error(t, err)
+			} else {
+				require.NoError(t, err)
+				require.NotNil(t, client)
+			}
+		})
+	}
+}
+
+func TestConnectClientWithRPCs(t *testing.T) {
+	tcs := []struct {
+		name    string
+		network string
+		RPCs    []string
+		wantErr bool
+	}{
+		{
+			name:    "ConnectClientWithRPCs, Holesky",
+			network: "holesky",
+			RPCs:    []string{"https://endpoints.omniatech.io/v1/eth/holesky/public", "https://ethereum-holesky.blockpi.network/v1/rpc/public"},
+			wantErr: false,
+		},
+		{
+			name:    "ConnectClientWithRPCs, Holesky, invalid RPC",
+			network: "holesky",
+			RPCs:    []string{"https://www.google.com"},
+			wantErr: true,
+		},
+		{
+			name:    "ConnectClientWithRPCs, invalid Network RPCs",
+			network: "holesky",
+			RPCs:    []string{"https://eth.llamarpc.com"}, // Mainnet RPC
+			wantErr: true,
+		},
+		{
+			name:    "ConnectClient, Mainnet",
+			network: "mainnet",
+			RPCs:    []string{"https://eth.llamarpc.com"},
+			wantErr: false,
+		},
+	}
+	for _, tc := range tcs {
+		t.Run(tc.name, func(t *testing.T) {
+			client, err := ConnectClient(tc.network, tc.RPCs...)
+			if tc.wantErr {
+				require.Error(t, err)
+			} else {
+				require.NoError(t, err)
+				require.NotNil(t, client)
+			}
+		})
+	}
+}