feat(nodebuilder): add ip resolving capabilities to core.ip (#2277)

Co-authored-by: Hlib Kanunnikov <hlibwondertan@gmail.com>

nodebuilder/core/flags.go

@@ -2,6 +2,7 @@ package core
 
 import (
 	"fmt"
+	"net"
 
 	"github.com/spf13/cobra"
 	flag "github.com/spf13/pflag"
@@ -21,7 +22,8 @@ func Flags() *flag.FlagSet {
 		coreFlag,
 		"",
 		"Indicates node to connect to the given core node. "+
-			"Example: <ip>, 127.0.0.1. Assumes RPC port 26657 and gRPC port 9090 as default unless otherwise specified.",
+			"Example: <ip>, 127.0.0.1. <dns>, subdomain.domain.tld "+
+			"Assumes RPC port 26657 and gRPC port 9090 as default unless otherwise specified.",
 	)
 	flags.String(
 		coreRPCFlag,
@@ -37,10 +39,7 @@ func Flags() *flag.FlagSet {
 }
 
 // ParseFlags parses Core flags from the given cmd and saves them to the passed config.
-func ParseFlags(
-	cmd *cobra.Command,
-	cfg *Config,
-) error {
+func ParseFlags(cmd *cobra.Command, cfg *Config) error {
 	coreIP := cmd.Flag(coreFlag).Value.String()
 	if coreIP == "" {
 		if cmd.Flag(coreGRPCFlag).Changed || cmd.Flag(coreRPCFlag).Changed {
@@ -49,10 +48,22 @@ func ParseFlags(
 		return nil
 	}
 
+	ip := net.ParseIP(coreIP)
+	if ip == nil {
+		ips, err := net.LookupIP(coreIP)
+		if err != nil {
+			return fmt.Errorf("failed to resolve DNS record: %v", err)
+		}
+		if len(ips) == 0 {
+			return fmt.Errorf("no IP addresses found for DNS record")
+		}
+		ip = ips[0]
+	}
+
 	rpc := cmd.Flag(coreRPCFlag).Value.String()
 	grpc := cmd.Flag(coreGRPCFlag).Value.String()
 
-	cfg.IP = coreIP
+	cfg.IP = ip.String()
 	cfg.RPCPort = rpc
 	cfg.GRPCPort = grpc
 	return nil