add hint setting EVM Json-RPC url

Author: 0xbcdev

cmd/query/evm.go

@@ -2,6 +2,7 @@ package query
 
 import (
 	"bytes"
+	"context"
 	"encoding/hex"
 	"fmt"
 	"github.com/bcdevtools/devd/v2/cmd/types"
@@ -117,6 +118,14 @@ func mustGetEthClient(cmd *cobra.Command, fallbackDeprecatedFlagHost bool) (*eth
 	ethClient8545, err := ethclient.Dial(rpc)
 	utils.ExitOnErr(err, "failed to connect to EVM Json-RPC")
 
+	// pre-flight check to ensure the connection is working
+	_, err = ethClient8545.BlockNumber(context.Background())
+	if err != nil && strings.Contains(err.Error(), "connection refused") {
+		utils.PrintlnStdErr("ERR: failed to connect to EVM Json-RPC, please check the connection and try again.")
+		utils.PrintfStdErr("ERR: if you are using a custom EVM Json-RPC, please provide it via flag '--%s <your_custom>' or setting environment variable 'export %s=<your_custom>'.\n", flagRpc, constants.ENV_EVM_RPC)
+		os.Exit(1)
+	}
+
 	return ethClient8545, rpc
 }
 

constants/varcons.go

@@ -4,5 +4,5 @@ package constants
 
 //goland:noinspection GoSnakeCaseUsage
 var (
-	VERSION = "2.0.2"
+	VERSION = "2.0.3"
 )