Crate obs_types 

Foundation enums for the obs SDK.

Every other crate in the workspace depends on this one. The seven enums defined here form the vocabulary of the wire envelope (10-data-model.md § 2-5) — Tier, Severity, FieldKind, Cardinality, Classification, MetricKind, SamplingReason.

All enums:

• derive Copy + Clone + Debug + PartialEq + Eq + Hash,
• implement buffa::Enumeration so they live on the wire,
• serialize/deserialize via serde for obs.yaml config,
• expose const fn helpers used by compile-time lints (e.g. Cardinality::is_label_compatible, Cardinality::cap, Severity::as_str).

Vocabulary changes here cause an envelope format_ver bump (per 10-data-model.md § 6 and 61-crates-and-features.md § 4). That’s the intended forcing function.

Structs

UnknownVariant

Error returned by TryFrom<&str> and FromStr parsers when an unknown enum name is encountered. Each enum in this crate uses this type to preserve a uniform error surface across the vocabulary.

Enums

Cardinality

Bound on the number of distinct values a field admits at runtime.

Classification

Security/PII classification of a field.

FieldKind

Role of a field on a wide event. Drives codegen, OTel mapping, and lints.

MetricKind

Metric type for a MEASUREMENT field. See 12-schema-and-codegen.md § 2.

SamplingReason

Provenance recorded on the envelope explaining why an event was kept.

Severity

Six-level severity matching OTel SeverityNumber buckets.

Tier

Primary durable destination for an event.