inancgumus/learngo · error

record.page cannot be empty

Error message

record.page cannot be empty

What it means

Sentinel validation error from the pipe package's internal validate() guard: after a record is decoded (via UnmarshalText or UnmarshalJSON), the page field is the empty string. It fires because the decoded log record lacks a page path, which the parser requires as a mandatory column alongside domain; the record is rejected before it is aggregated.

Source

Thrown at logparser/v5/pipe/record.go:98

	return json.Marshal(rj)
}

// parseStr helps UnmarshalText for string to positive int parsing.
func parseStr(name, v string) (int, error) {
	n, err := strconv.Atoi(v)
	if err != nil {
		return 0, fmt.Errorf("Record.UnmarshalText %q: %v", name, err)
	}
	return n, nil
}

// validate whether a parsed record is valid or not.
func validate(r record) (err error) {
	switch {
	case r.domain == "":
		err = errors.New("record.domain cannot be empty")
	case r.page == "":
		err = errors.New("record.page cannot be empty")
	case r.visits < 0:
		err = errors.New("record.visits cannot be negative")
	case r.uniques < 0:
		err = errors.New("record.uniques cannot be negative")
	}
	return
}

View on GitHub (pinned to 3c475a78e5)

Solutions

1. Ensure each record has a non-empty page value before unmarshaling.
2. Default missing pages to a sentinel like "/unknown" if acceptable.
3. Trim input; if whitespace-only pages should count, fill a value upstream.
4. Skip and log invalid records instead of failing.

Example fix

// before
{"domain":"example.com","visits":10}
// after
{"domain":"example.com","page":"/","visits":10}

if strings.TrimSpace(rec.Page) == "" {
    rec.Page = "/unknown" // or reject
}

func hasPage(r record) bool { return strings.TrimSpace(r.page) != "" }

var rec record
err := rec.UnmarshalJSON(data)
if err != nil {
    if strings.Contains(err.Error(), "record.page cannot be empty") {
        log.Printf("dropping record without page: %s", data)
        return nil
    }
    return err
}

When it happens

Trigger: UnmarshalText/UnmarshalJSON receive a record where page is missing, null, or "" (while domain is non-empty, since domain is checked first).

Common situations: Log lines missing the URL/path column; JSON exporters emitting records without the page key; rows where the page was trimmed to nothing.

Understand the failure class

Background: Schema validation failed / invalid input schema: payload rejected because its shape doesn't match the expected schema — this error's family across 28 libraries.

Related errors

• record.domain cannot be empty
• record.domain cannot be empty|record.page cannot be empty|re
• invalid number
• record.visits cannot be negative
• record.uniques cannot be negative

AI-assisted analysis of inancgumus/learngo@3c475a78e5 (2026-09-02). Data as JSON: /api/errors/9ce4fe82d655784f. Report an issue: GitHub.