crowdsecurity/crowdsec · error

unable to parse yaml file %s : %w

Error message

unable to parse yaml file %s : %w

What it means

After reading the appsec config file, LoadByPath unmarshals it into a temporary AppsecConfig with yaml.UnmarshalStrict. Strict mode rejects unknown keys, so this error fires both for syntactically invalid YAML and for config keys that do not exist on the struct. The wrapped yaml error names the exact line and offending key.

Source

Thrown at pkg/appsec/appsec.go:673

	/* wc.Name is actually the datasource name.*/
	wc.Logger = wc.Logger.Dup().WithField("name", wc.Name)
	wc.Logger.Logger.SetLevel(*wc.LogLevel)
}

func (wc *AppsecConfig) LoadByPath(file string) error {
	wc.Logger.Debugf("loading config %s", file)

	yamlFile, err := os.ReadFile(file)
	if err != nil {
		return fmt.Errorf("unable to read file %s : %w", file, err)
	}

	// as  LoadByPath can be called several time, we append rules/hooks, but override other options
	var tmp AppsecConfig

	err = yaml.UnmarshalStrict(yamlFile, &tmp)
	if err != nil {
		return fmt.Errorf("unable to parse yaml file %s : %w", file, err)
	}

	// Normalize phase-scoped sections: merge rules, options, and variables_tracking
	// into flat fields. Hooks stay in the phase sections for Build() to compile separately.
	tmp.normalizePhaseScoped()

	if wc.Name == "" && tmp.Name != "" {
		wc.Name = tmp.Name
	}

	// We can append rules/hooks
	if tmp.OutOfBandRules != nil {
		wc.OutOfBandRules = append(wc.OutOfBandRules, tmp.OutOfBandRules...)
	}

	if tmp.InBandRules != nil {
		wc.InBandRules = append(wc.InBandRules, tmp.InBandRules...)
	}

View on GitHub (pinned to 909b515798)

Solutions

1. Read the wrapped yaml error line/column and fix the YAML syntax or the unknown key at that line
2. Compare your keys against the documented AppsecConfig fields for your CrowdSec version
3. Replace tabs with spaces and validate indentation with a YAML linter
4. Pin configs to keys supported by your installed version when copying examples from newer docs

Example fix

// before
on_sucess: break
// after
on_success: break

When it happens

Trigger: LoadByPath on a YAML file with syntax errors (bad indentation, tabs, unclosed quotes); a typo'd or unknown top-level key (strict unmarshaling); a value of the wrong type for a known field.

Common situations: Hand-edited appsec-config with a misspelled option like 'on_sucess' instead of 'on_success'; tabs instead of spaces; mixing appsec-config keys into a rules file loaded as appsec config; config from an older/newer CrowdSec version using removed keys.

Understand the failure class

• Parsing and encoding errors: unexpected token, malformed input — why parsers reject input and how to find the real culprit.

Related errors

• no appsec_config provided
• ref cannot be empty
• on_challenge hooks are only valid in-band, not under outofba
• on_challenge_submit hooks are only valid in-band, not under
• max_body_size must be a positive integer

AI-assisted analysis of crowdsecurity/crowdsec@909b515798 (2026-09-06). Data as JSON: /api/errors/071c9e2ee313d4ec. Report an issue: GitHub.