GoogleContainerTools/skaffold · error

unsupported trigger: %s

Error message

unsupported trigger: %s

What it means

NewTrigger creates the file-watch trigger from the configured trigger mode. Only "polling", "notify" (fsnotify), and "manual" are supported; any other value falls to the default case and is rejected. The error echoes the invalid trigger string from the config.

Source

Thrown at pkg/skaffold/trigger/triggers.go:63

	WatchPollInterval() int
}

// NewTrigger creates a new trigger.
func NewTrigger(cfg Config, isActive func() bool) (Trigger, error) {
	switch strings.ToLower(cfg.Trigger()) {
	case "polling":
		return &pollTrigger{
			Interval: time.Duration(cfg.WatchPollInterval()) * time.Millisecond,
			isActive: isActive,
		}, nil
	case "notify":
		return newFSNotifyTrigger(cfg, isActive), nil
	case "manual":
		return &manualTrigger{
			isActive: isActive,
		}, nil
	default:
		return nil, fmt.Errorf("unsupported trigger: %s", cfg.Trigger())
	}
}

func newFSNotifyTrigger(cfg Config, isActive func() bool) Trigger {
	workspaces := map[string]struct{}{}
	for _, a := range cfg.Artifacts() {
		workspaces[a.Workspace] = struct{}{}
	}
	return fsNotify.New(workspaces, isActive, cfg.WatchPollInterval())
}

// pollTrigger watches for changes on a given interval of time.
type pollTrigger struct {
	Interval time.Duration
	isActive func() bool
}

// Debounce tells the watcher to debounce rapid sequence of changes.

View on GitHub (pinned to a1189de023)

Solutions

1. Use one of the supported values: polling, notify, or manual
2. Fix the --trigger flag value or the config source feeding Trigger()
3. Default to "notify" if the value is empty/unknown before calling NewTrigger

Example fix

// before
skaffold dev --trigger=fswatch

// after
skaffold dev --trigger=notify

var validTriggers = map[string]bool{"polling": true, "notify": true, "manual": true}
if !validTriggers[triggerStr] {
    return fmt.Errorf("invalid --trigger %q; use polling, notify, or manual", triggerStr)
}

tr, err := trigger.NewTrigger(cfg, isActive)
if err != nil && strings.Contains(err.Error(), "unsupported trigger") {
    tr, err = trigger.NewTrigger(defaultTriggerConfig(cfg), isActive) // fall back to notify
}

When it happens

Trigger: Calling NewTrigger with a Config whose Trigger() returns a string outside {polling, notify, manual} — e.g. from a CLI flag like --trigger=? or an unresolved config value.

Common situations: Typo in --trigger flag value (e.g. --trigger=watch); stale scripts passing removed trigger names; env/config plumbing passing empty or localized strings.

Related errors

• `apply` requires at least one manifest argument
• `exec` requires exactly one action to execute
• `config-dependencies add` requires exactly one file path arg
• `jobManifestPaths modify` requires exactly one manifest file
• `inspect namespaces list` requires exactly one manifest file

AI-assisted analysis of GoogleContainerTools/skaffold@a1189de023 (2026-09-05). Data as JSON: /api/errors/9518459671d327b7. Report an issue: GitHub.