Added validation for --registry-mirror flag

cmd/minikube/cmd/start.go

@@ -24,6 +24,7 @@ import (
 	"os"
 	"os/exec"
 	"path/filepath"
+	"regexp"
 	"runtime"
 	"strconv"
 	"strings"
@@ -437,6 +438,8 @@ func generateConfig(cmd *cobra.Command, k8sVersion string) (cfg.Config, error) {
 		console.OutStyle("success", "using image repository %s", repository)
 	}
 
+	validateRegistryMirror(registryMirror)
+
 	cfg := cfg.Config{
 		MachineConfig: cfg.MachineConfig{
 			MinikubeISO:         viper.GetString(isoURL),
@@ -755,3 +758,16 @@ func saveConfig(clusterConfig cfg.Config) error {
 	}
 	return nil
 }
+
+// This function validates if the --registry--mirror args
+// match the format of http://localhost
+func validateRegistryMirror(registryMirror []string) {
+	urlRe := regexp.MustCompile(`http:\/\/(.+?)`)
+	if len(registryMirror) > 0 {
+		for _, loc := range registryMirror {
+			if !urlRe.MatchString(loc) {
+				exit.WithCode(exit.Failure, "url provided with --registry-mirror flag is invalid %q", loc)
+			}
+		}
+	}
+}