Struct DynamicGauge 

pub struct DynamicGauge { /* private fields */ }

Gauge keyed by runtime label sets.

Uses sharded index for key->series lookup for concurrent access.

Implementations

impl DynamicGauge

pub fn new(shard_count: usize) -> Self

Creates a new runtime-labeled gauge.

pub fn with_max_series(shard_count: usize, max_series: usize) -> Self

Creates a new runtime-labeled gauge with a series cardinality cap.

When the number of unique label sets approximately reaches max_series, new label sets are redirected into a single overflow series (__ft_overflow=true). The cap is checked via a lock-free atomic counter, so concurrent inserts may briefly overshoot by the number of in-flight writers before the overflow kicks in.

pub fn series(&self, labels: &[(&str, &str)]) -> DynamicGaugeSeries

Resolve a reusable series handle for labels.

Preferred for hot paths when labels come from a finite active set.

pub fn set(&self, labels: &[(&str, &str)], value: f64)

Set the gauge value for the series identified by labels.

pub fn get(&self, labels: &[(&str, &str)]) -> f64

Get the current value for the series identified by labels.

pub fn snapshot(&self) -> Vec<(DynamicLabelSet, f64)>

Returns a snapshot of all label-set/value pairs.

pub fn cardinality(&self) -> usize

Returns the current number of distinct label sets.

pub fn overflow_count(&self) -> u64

Returns the number of records routed to the overflow bucket.

A non-zero value indicates the cardinality cap was hit and label fidelity is being lost. Use this to alert on cardinality pressure.

pub fn evict_stale(&self, max_staleness: u32) -> usize

Evict series that haven’t been accessed for max_staleness cycles.

Call this after advance_cycle() in your exporter task. Series are marked as evicted (so cached handles see the tombstone), then removed from the index.

Protected series (Arc::strong_count > 1) are never evicted - someone holds a DynamicGaugeSeries handle to them.

Returns the number of series evicted.

Trait Implementations

impl ClickHouseExport for DynamicGauge

fn export_clickhouse( &self, batch: &mut ClickHouseMetricBatch, name: &str, description: &str, time_unix_nano: u64, )

impl DogStatsDExport for DynamicGauge

fn export_dogstatsd( &self, output: &mut String, name: &str, tags: &[(&str, &str)], )

Export this metric to the output string in DogStatsD format.

impl OtlpExport for DynamicGauge

fn export_otlp( &self, metrics: &mut Vec<Metric>, name: &str, description: &str, time_unix_nano: u64, )

impl PrometheusExport for DynamicGauge

fn export_prometheus(&self, output: &mut String, name: &str, help: &str)

Export this metric to the output string.