GoogleContainerTools/skaffold · error

unsupported prefix:

Error message

unsupported prefix: 

What it means

The kubernetes log formatter's prefix function panics when deploy.logs.prefix in skaffold config holds a value outside the supported set (container, pod, podAndContainer, none, auto...). clusterPrefix delegates to prefix(), which expects the config to have been validated against the enum earlier.

Solutions

1. Fix deploy.logs.prefix in skaffold.yaml to one of: none, container, pod, podAndContainer (or omit it for auto)
2. Run schema validation / `skaffold diagnose` to catch invalid enum values before deploy
3. Upgrade or align skaffold version with the config's apiVersion if an enum value was renamed

Example fix

// before
deploy:
  logs:
    prefix: pods
// after
deploy:
  logs:
    prefix: pod

var validPrefixes = map[string]bool{"none": true, "container": true, "pod": true, "podAndContainer": true}
if p := cfg.Deploy.Logs.Prefix; p != "" && p != "auto" && !validPrefixes[p] {
  return fmt.Errorf("invalid deploy.logs.prefix %q", p)
}

func isValidPrefix(p string) bool {
  switch p {
  case "", "auto", "none", "container", "pod", "podAndContainer":
    return true
  }
  return false
}

func safePrefix(c Config, pod *v1.Pod, ctr v1.ContainerStatus) (s string) {
  defer func() { if recover() != nil { s = autoPrefix(pod, ctr) } }()
  return clusterPrefix(c, pod, ctr)
}

When it happens

Trigger: Setting deploy.logs.prefix to a misspelled or unsupported string in skaffold.yaml (e.g. 'pods', 'containerName') such that the default branch of the switch is reached at runtime.

Common situations: Typo in skaffold.yaml logs prefix; config edited by hand or by tooling that bypassed schema validation; older config file carried forward across a skaffold version that renamed an enum value.

Understand the failure class

Background: Invalid enum value errors: "Unknown type", "Invalid scope", "must be one of" — when a string is not on the library's allowed list — this error's family across 23 libraries.

Related errors

• Unknown artifact
• bucket name is empty
• caching remote dependency
• cannot find available port
• cannot parse the name template on user defined port…

AI-assisted analysis of GoogleContainerTools/skaffold@a1189de023 (2026-09-05). Data as JSON: /api/errors/a64ea406f357ba76. Report an issue: GitHub.

Appendix: source

Thrown at pkg/skaffold/kubernetes/logger/formatter.go:127

		}
	}
	if !present {
		c = config.DefaultPipeline()
	}
	switch c.Deploy.Logs.Prefix {
	case "auto":
		if pod.Name != container.Name {
			return podAndContainerPrefix(pod, container)
		}
		return autoPrefix(pod, container)
	case "container":
		return containerPrefix(container)
	case "podAndContainer":
		return podAndContainerPrefix(pod, container)
	case "none":
		return ""
	default:
		panic("unsupported prefix: " + c.Deploy.Logs.Prefix)
	}
}

func autoPrefix(pod *v1.Pod, container v1.ContainerStatus) string {
	if pod.Name != container.Name {
		return fmt.Sprintf("[%s %s]", pod.Name, container.Name)
	}
	return fmt.Sprintf("[%s]", container.Name)
}

func containerPrefix(container v1.ContainerStatus) string {
	return fmt.Sprintf("[%s]", container.Name)
}

func podAndContainerPrefix(pod *v1.Pod, container v1.ContainerStatus) string {
	return fmt.Sprintf("[%s %s]", pod.Name, container.Name)
}

View on GitHub (pinned to a1189de023)