Struct Registry 

pub struct Registry { /* private fields */ }

A registry mapping metric names (+ optional fixed labels) to metrics.

Implementations

impl Registry

pub fn new() -> Self

Create an empty registry.

pub fn counter(&self, key: &str, help: &str) -> Arc<Counter>

Register (or fetch) a counter. key must be a valid Prometheus series name with optional {label="v"} suffix.

Panics if key is already registered as a histogram; a silent overwrite would detach the existing metric from the registry and lose every observation collected against it. Also panics if key contains a byte that would corrupt Prometheus text exposition (cross-line bytes anywhere; " or \\ in the base name — both stay legal inside the label section) — this catches accidental interpolation of attacker-controlled strings into a metric key at registration rather than surfacing corrupt scrape output later.

pub fn histogram(&self, key: &str, help: &str) -> Arc<Histogram>

Register (or fetch) a histogram with default latency buckets.

Panics if key is already registered as a counter; a silent overwrite would detach the existing metric from the registry and lose every observation collected against it. Same key-byte guard as Self::counter.

pub fn histogram_with_bounds( &self, key: &str, help: &str, bounds_us: &[u64], ) -> Arc<Histogram>

Register (or fetch) a histogram with explicit bucket bounds. Use WIDE_LATENCY_BOUNDS_US for spans dominated by network I/O (upstream LLM streaming, reconciler filesystem scans); use DEFAULT_LATENCY_BOUNDS_US for fast internal stages.

pub fn render(&self) -> String

Render the registry in Prometheus text exposition format.

Histogram observations are stored internally in microseconds but rendered in seconds (le bounds and _sum), per Prometheus base-unit convention. Histogram metric names should therefore end in _seconds.

Round-19: HELP text is escaped per the Prometheus text format spec (\ → \\, LF → \n). A future counter/histogram registration whose HELP contained a newline would otherwise silently corrupt the scrape response — Prometheus would parse the remainder of the HELP text as metric samples and fail.

Trait Implementations

impl Default for Registry

fn default() -> Registry

Returns the “default value” for a type.