fix:[CI-13562]:improve error message for anonymous connector used

docker.go

@@ -177,7 +177,12 @@ func (p Plugin) Exec() error {
 		baseConnectorLogin.Password = p.BaseImagePassword
 
 		cmd := commandLogin(baseConnectorLogin)
-
+		if p.BaseImageUsername == "" {
+			return fmt.Errorf("Username cannot be empty. The base image connector requires authenticated access. Please either use an authenticated connector, or remove the base image connector.")
+		}
+		if p.BaseImagePassword == "" {
+			return fmt.Errorf("Password cannot be empty. The base image connector requires authenticated access. Please either use an authenticated connector, or remove the base image connector.")
+		}
 		raw, err := cmd.CombinedOutput()
 		if err != nil {
 			out := string(raw)

internal/docker/config.go

@@ -52,10 +52,10 @@ func (c *Config) CreateDockerConfigJson(credentials []RegistryCredentials) ([]by
 		if cred.Registry != "" {
 
 			if cred.Username == "" {
-				return nil, fmt.Errorf("Username must be specified for registry: %s", cred.Registry)
+				return nil, fmt.Errorf("Username cannot be empty. The base image connector requires authenticated access. Please either use an authenticated connector, or remove the base image connector.")
 			}
 			if cred.Password == "" {
-				return nil, fmt.Errorf("Password must be specified for registry: %s", cred.Registry)
+				return nil, fmt.Errorf("Password cannot be empty. The base image connector requires authenticated access. Please either use an authenticated connector, or remove the base image connector.")
 			}
 			c.SetAuth(cred.Registry, cred.Username, cred.Password)
 		}