Error Label

Low-cardinality label for errors, useful for metrics and logging.

ErrorLabel wraps a Cow<'static, str> to hold either a static string literal or a heap-allocated String. It is intended for use as a metric tag value or structured log field and should always be chosen from a small, bounded set of values.

Quick Start

use error_label::ErrorLabel;

// From a static string
let label: ErrorLabel = "timeout".into();
assert_eq!(label, "timeout");

// Dotted chain from parts
let label = ErrorLabel::from_parts(["http", "client", "timeout"]);
assert_eq!(label, "http.client.timeout");