validate decider host/port in config, not main

addresses review comment ava-labs/awm-relayer#344 (comment)

config/config.go

@@ -7,6 +7,9 @@ import (
 	"context"
 	"errors"
 	"fmt"
+	"net/url"
+	"strconv"
+	"strings"
 
 	"github.com/ava-labs/avalanchego/ids"
 	"github.com/ava-labs/avalanchego/utils/constants"
@@ -121,6 +124,22 @@ func (c *Config) Validate() error {
 	}
 	c.blockchainIDToSubnetID = blockchainIDToSubnetID
 
+	if c.DeciderPort != nil {
+		portStr := strconv.FormatUint(uint64(*c.DeciderPort), 10)
+
+		host := c.DeciderHost
+		if len(host) == 0 {
+			host = "localhost"
+		}
+
+		uri := strings.Join([]string{host, portStr}, ":")
+
+		_, err := url.ParseRequestURI(uri)
+		if err != nil {
+			return fmt.Errorf("Invalid decider URI: %w", err)
+		}
+	}
+
 	return nil
 }
 

main/main.go

@@ -8,7 +8,6 @@ import (
 	"fmt"
 	"log"
 	"net/http"
-	"net/url"
 	"os"
 	"runtime"
 	"strconv"
@@ -464,18 +463,11 @@ func createDeciderClient(host string, port *uint16) (*grpc.ClientConn, error) {
 		host = "localhost"
 	}
 
-	uri := strings.Join(
-		[]string{host, strconv.FormatUint(uint64(*port), 10)},
-		":",
-	)
-
-	_, err := url.ParseRequestURI(uri)
-	if err != nil {
-		return nil, fmt.Errorf("Invalid URI: %w", err)
-	}
-
 	client, err := grpc.NewClient(
-		uri,
+		strings.Join(
+			[]string{host, strconv.FormatUint(uint64(*port), 10)},
+			":",
+		),
 		grpc.WithTransportCredentials(insecure.NewCredentials()),
 	)
 	if err != nil {