Struct SubjectDecl 

#[non_exhaustive]
pub struct SubjectDecl {

    pub path: String,
    pub class: Declared<Class>,
    pub type_name: String,
    pub kind: Option<Declared<SubjectKind>>,
    pub common: Option<Declared<CommonFamily>>,
    pub since: Option<String>,
    pub description: Option<String>,
    pub qos: Option<Declared<QosProfile>>,
    pub ttl_s: Option<i64>,
    pub unit: Option<String>,
    pub rate: Option<RateClass>,
    pub cardinality: Option<i64>,
    pub encoding: Option<WireEncoding>,
}

One [[subject]] entry of a served registry slice. #[non_exhaustive]: every version of this type so far has been the previous one plus a field (encoding v1.5, blob v1.8, media v1.16), and each of those was a breaking change for anyone constructing one. It is a parse result, not a thing callers build — parse_slice is the constructor — so the attribute costs the intended use nothing and stops the next field being a break (#325).

Fields (Non-exhaustive)

Non-exhaustive structs could have additional fields added in future. Therefore, non-exhaustive structs cannot be constructed in external crates using the traditional Struct { .. } syntax; cannot be matched against without a wildcard ..; and struct update syntax will not work.

path: String

The subject pattern, base-relative to <class>/<producer> — e.g. disk/{mount}/used.

class: Declared<Class>

telemetry | state | events (RFC 04 §1).

type_name: String

The payload type name, as the producer declares it.

kind: Option<Declared<SubjectKind>>

What the leaf value is — counter | gauge | text | bool (RFC 08 §2, v1.32), when declared. Absent means unchecked: a judge answers not asked (RFC 13 §3).

common: Option<Declared<CommonFamily>>

common = "health|errors|sensor|…" — which of the RFC 08 §5 framework state roles this subject declares itself as, when it declares one.

Carried since #50: a producer serves its registry TOML verbatim, so this field has always ridden the wire; the slice type simply dropped it on the floor. That was invisible until registry export --as toml made the parse→emit path a round trip somebody might feed back into a build, where a lost common silently changes the generated AnySubject::common_state().

since: Option<String>

Registry version this subject first appeared in.

description: Option<String>

qos: Option<Declared<QosProfile>>

The declared QoS profile (RFC 04 §3), when the slice carries one.

ttl_s: Option<i64>

State-subject freshness bound (RFC 04 §1.2), when declared.

unit: Option<String>

The subject’s unit (RFC 08 §4), when declared.

rate: Option<RateClass>

Events rate class (RFC 04 §1.3), when declared.

cardinality: Option<i64>

The declared key-population bound, when declared.

encoding: Option<WireEncoding>

The declared payload encoding (application/cbor, …), when declared (RFC 08 §2, v1.5). Resolution: sample Encoding > this > sniff. WireEncoding carries its own Other arm, so it needs no Declared wrapper — it has been this shape since v1.5.

Implementations

impl SubjectDecl

pub fn new(path: impl Into<String>, class: impl Into<Declared<Class>>) -> Self

A subject declaration with its two required columns; the optional ones are None and assignable — the fields stay pub, and #[non_exhaustive] blocks only literal construction.

Trait Implementations

impl Clone for SubjectDecl

fn clone(&self) -> SubjectDecl

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for SubjectDecl

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Eq for SubjectDecl

impl PartialEq for SubjectDecl

fn eq(&self, other: &SubjectDecl) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl StructuralPartialEq for SubjectDecl