What causes "unrecognized log_level %q: valid values are debug, info, error" in jaegertracing/jaeger?

Change log_level to one of: (empty), 'debug', 'info', 'error'

unrecognized log_level %q: valid values are debug, info, err

Error message

unrecognized log_level %q: valid values are debug, info, error

What it means

The Elasticsearch storage config allows an optional log_level that attaches client-side logging to the ES client. Only '', 'debug', 'info', and 'error' are accepted; anything else fails validation in validateLogLevel. This keeps operator typos from silently disabling the intended client logging.

Source

Thrown at internal/storage/elasticsearch/config/config.go:573

// write_mode carries no govalidator struct tag, so the whole-config Validate must
// check it explicitly.
func validateWriteMode(mode WriteMode) error {
	switch mode {
	case "", WriteModeAsync, WriteModeSync:
		return nil
	default:
		return fmt.Errorf("unrecognized write_mode %q: valid values are %q and %q", mode, WriteModeAsync, WriteModeSync)
	}
}

// validateLogLevel rejects an unrecognized log_level. An empty value is allowed
// and means no client logging is attached.
func validateLogLevel(level string) error {
	switch level {
	case "", "debug", "info", "error":
		return nil
	default:
		return fmt.Errorf("unrecognized log_level %q: valid values are debug, info, error", level)
	}
}

// rejectUnwiredKey builds the validation error for a config key that the current
// Elasticsearch client no longer reads, pointing operators at the PR that explains
// the change. The migration is always the same: remove the key.
func rejectUnwiredKey(key, reason string) error {
	return fmt.Errorf(
		"'%s' is no longer supported: %s; please remove the setting "+
			"(see https://github.com/jaegertracing/jaeger/pull/9076)",
		key, reason,
	)
}

View on GitHub (pinned to 806f444784)

Solutions

Change log_level to one of: (empty), 'debug', 'info', 'error'
Remove the log_level key to disable client logging
Use the component's general logging flags instead if you need levels like 'warn'

Example fix

// before
log_level: warning
// after
log_level: error

Defensive patterns

Strategy: validation

Validate before calling

validLogLevels := map[string]bool{"": true, "debug": true, "info": true, "error": true}
if !validLogLevels[cfg.LogLevel] {
    return fmt.Errorf("log_level must be one of: (empty), debug, info, error; got %q", cfg.LogLevel)
}

Prevention

Use the exact level strings from the Jaeger ES config docs
Do not reuse level names ('warn', 'trace') from other loggers
Run config validation in CI

When it happens

Trigger: Setting log_level in the Elasticsearch storage config (or the corresponding config field) to any string other than '', 'debug', 'info', or 'error' and calling Validate.

Common situations: Typo such as log_level: warning or log_level: trace (valid for other loggers but not here); copying a level name from a different component's config.

Understand the failure class

Background: "Invalid value" and "allowed values are" config errors: what your library rejected and how to fix it — this error's family across 41 libraries.

Related errors

AI-assisted analysis of jaegertracing/jaeger@806f444784 (2026-09-01). Data as JSON: /api/errors/7419541aa8960722. Report an issue: GitHub.