cloudflare/cloudflared · error

option type Generic not supported

Error message

option type Generic not supported

What it means

configFileSettings is the configuration-file adapter that satisfies the cli flag-source interface used to feed file-based settings into urfave/cli. Generic is the accessor for urfave/cli's generic flag type, which the file-settings backend does not implement, so it always returns this error. It exists only to satisfy the interface.

Source

Thrown at config/configuration.go:362

			for i, v := range slice {
				str, ok := v.(int)
				if !ok {
					return nil, fmt.Errorf("expected int, found %T for %v ", v, v)
				}
				intSlice[i] = str
			}
			return intSlice, nil
		}
		if v, ok := raw.([]int); ok {
			return v, nil
		}
		return nil, fmt.Errorf("expected int slice found %T for %s", raw, name)
	}
	return nil, nil
}

func (c *configFileSettings) Generic(name string) (cli.Generic, error) {
	return nil, errors.New("option type Generic not supported")
}

func (c *configFileSettings) Bool(name string) (bool, error) {
	if raw, ok := c.Settings[name]; ok {
		if v, ok := raw.(bool); ok {
			return v, nil
		}
		return false, fmt.Errorf("expected boolean found %T for %s", raw, name)
	}
	return false, nil
}

var configuration configFileSettings

func GetConfiguration() *Configuration {
	return &configuration.Configuration
}

View on GitHub (pinned to 2253eeeb25)

Solutions

1. Remove the offending option from the config file, or express its value with a supported type (string, bool, int, duration, string slice)
2. Do not call Generic on config-file settings; read such values directly from the settings map instead
3. Check which flag maps to a Generic type in the urfave/cli command definition and avoid setting it via the config file

Example fix

# before (config.yml)
some-generic-option:
  key: value
# after
# remove the option or use a supported scalar/list type
some-string-option: value

if _, isGeneric := flagValue.(cli.Generic); isGeneric {
    return errors.New("generic flags cannot be set from the config file")
}

func isUnsupportedGenericAccessor(err error) bool {
    return err != nil && strings.Contains(err.Error(), "option type Generic not supported")
}

val, err := settings.Generic(name)
if err != nil && strings.Contains(err.Error(), "Generic not supported") {
    // fall back to a supported accessor: settings.String(name), etc.
}

When it happens

Trigger: A configuration file defines a flag whose type resolves to the cli.Generic interface, and code calls configFileSettings.Generic(name) to read it (or the flag-source machinery routes a lookup to Generic).

Common situations: A user puts an option in config.yml whose corresponding CLI flag is a Generic/placeholder type; custom code built on cloudflared's config package reads a settings map through the cli flag-source interface.

Understand the failure class

Background: UnsupportedOperationException and "is not supported" errors: when a library deliberately refuses a call — this error's family across 30 libraries.

Related errors

• --unix-socket must be used exclusively.
• Specified origin urls using both --url and argument. Decide
• unable to find config file
• An api-url was not provided for the Cloudflare API client
• Hostname patterns can have at most one wildcard character ("

AI-assisted analysis of cloudflare/cloudflared@2253eeeb25 (2026-09-06). Data as JSON: /api/errors/209dacfec666510c. Report an issue: GitHub.