amir20/dozzle · error

invalid filter

Error message

invalid filter: %s

What it means

ParseContainerFilter converts a comma-separated 'key=value' filter string into a map. If any comma-separated token lacks an '=' separator the whole parse fails with 'invalid filter'. Used to translate user-supplied label filters into Docker API filters.

Solutions

1. Write each token as key=value, comma-separated with no bare values
2. For label filtering use the form 'label=key' or 'label=key=value' as the Docker API expects
3. Remove empty segments caused by trailing/double commas

Example fix

// before
ParseContainerFilter("label=env,prod")
// after
ParseContainerFilter("label=env,label=prod")

func validFilter(f string) bool {
  for _, tok := range strings.Split(f, ",") {
    if !strings.Contains(tok, "=") { return false }
  }
  return true
}

When it happens

Trigger: ParseContainerFilter receives a filter string where a token between commas has no '=' (e.g. 'label=env,prod' where 'prod' has no key). Raised in the strings.SplitSeq loop when strings.Cut returns ok=false. Also hit via decodeUsersFromFile paths.

Common situations: Typo omitting '=' between key and value; label name-only filtering without 'label=' prefix; spaces or trailing commas creating bare tokens; copied filter strings losing characters.

Understand the failure class

Background: "Invalid ... format", "must be in format X", "does not look like a ..." — invalid argument format errors across CLI tools and libraries — this error's family across 17 libraries.

Related errors

• user has an invalid filter
• unknown action
• unknown action
• unknown action
• Failed to save alert

AI-assisted analysis of amir20/dozzle@d9463cbe21 (2026-09-07). Data as JSON: /api/errors/33f4117c687f45a1. Report an issue: GitHub.

Appendix: source

Thrown at internal/container/types.go:238

	Host            string            `json:"host"`
	ActorID         string            `json:"actorId"`
	ActorAttributes map[string]string `json:"actorAttributes,omitempty"`
	Time            time.Time         `json:"time"`
	Container       *Container        `json:"-"`
}

type ContainerLabels map[string][]string

func ParseContainerFilter(commaValues string) (ContainerLabels, error) {
	filter := make(ContainerLabels)
	if commaValues == "" {
		return filter, nil
	}

	for val := range strings.SplitSeq(commaValues, ",") {
		before, after, ok := strings.Cut(val, "=")
		if !ok {
			return nil, fmt.Errorf("invalid filter: %s", filter)
		}
		key := before
		val := after
		filter[key] = append(filter[key], val)
	}

	return filter, nil
}

func (f ContainerLabels) Exists() bool {
	return len(f) > 0
}

type LogPosition string

const (
	Beginning LogPosition = "start"
	Middle    LogPosition = "middle"

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