What causes "missing mandatory 'type' field in %s: %s" in crowdsecurity/crowdsec?

Add "type" to the offending line with one of the supported values (see validMapEntryTypes, e.g. ip, range, string, regex, url).

crowdsecurity/crowdsec · error

missing mandatory 'type' field in %s: %s

Error message

missing mandatory 'type' field in %s: %s

What it means

After validating 'pattern' and 'tag', fileMapInit requires a 'type' field that classifies the entry (used by existsInFileMaps to route lookups). This error is thrown when the JSON line lacks the 'type' key or it is empty.

Source

Thrown at pkg/exprhelpers/filemap.go:60

// fileMapInit parses a single JSON line and appends it to the fileMapEntry for the given filename.
// Three fields are mandatory: "pattern", "tag", and "type" (one of: "equals", "contains", "regex").
func fileMapInit(filename string, line string) error {
	var record map[string]string
	if err := json.Unmarshal([]byte(line), &record); err != nil {
		return fmt.Errorf("failed to parse JSON line in %s: %w", filename, err)
	}

	if record["pattern"] == "" {
		return fmt.Errorf("missing mandatory 'pattern' field in %s: %s", filename, line)
	}

	if record["tag"] == "" {
		return fmt.Errorf("missing mandatory 'tag' field in %s: %s", filename, line)
	}

	entryType := record["type"]
	if entryType == "" {
		return fmt.Errorf("missing mandatory 'type' field in %s: %s", filename, line)
	}

	if !slices.Contains(validMapEntryTypes, entryType) {
		return fmt.Errorf("unknown entry type '%s' in %s (supported: %s): %s",
			entryType, filename, strings.Join(validMapEntryTypes, ", "), line)
	}

	if entryType == "regex" {
		if _, err := regexp.Compile(record["pattern"]); err != nil {
			log.Warningf("invalid regex pattern in %s: %s", filename, err)
		}
	}

	if dataFileMap[filename] == nil {
		dataFileMap[filename] = &fileMapEntry{filename: filename}
	}

	dataFileMap[filename].rows = append(dataFileMap[filename].rows, record)

View on GitHub (pinned to 909b515798)

Solutions

Add "type" to the offending line with one of the supported values (see validMapEntryTypes, e.g. ip, range, string, regex, url).
Update the data file to the current filemap format per the crowdsec hub data-file documentation.
Validate each line with a script requiring pattern, tag, and type before loading.
Pull the latest version of the data file from the hub if it is maintained upstream.

Example fix

// before
{"pattern":"example.com","tag":"tracker"}
// after
{"pattern":"example.com","tag":"tracker","type":"string"}

Defensive patterns

Strategy: validation

Validate before calling

for i, line := range lines {
	var rec map[string]string
	json.Unmarshal([]byte(line), &rec)
	if rec["type"] == "" {
		return fmt.Errorf("line %d: missing 'type'", i+1)
	}
}

Prevention

Check data-file format docs for the current crowdsec version after upgrades
Migrate old-format data files explicitly rather than loading them as-is
Keep a canonical template of the filemap line format in your config repo

When it happens

Trigger: Calling FileInit (via fileMapInit) on a filemap line such as {"pattern":"evil.example.com","tag":"malware"} with no "type" key, or "type":"".

Common situations: Older data-file formats predating the 'type' field that were never migrated; hand-written lookup files where the author only knew about pattern/tag; hub data files copied from an outdated source.

Understand the failure class

Background: "is required", "must be set", "missing required field": configuration validation errors across open-source libraries — this error's family across 36 libraries.

Related errors

AI-assisted analysis of crowdsecurity/crowdsec@909b515798 (2026-09-06). Data as JSON: /api/errors/45708b0a8c8ab158. Report an issue: GitHub.