Struct LabelGuardedMetricVec

pub struct LabelGuardedMetricVec<T: MetricVecBuilder, const N: usize> {
    inner: MetricVec<T>,
    info: Arc<Mutex<LabelGuardedMetricsInfo<N>>>,
    labels: [&'static str; N],
}

An RAII metrics vec with labels.

LabelGuardedMetricVec enhances the [MetricVec] to ensure the set of labels to be correctly removed from the Prometheus client once being dropped. This is useful for metrics that are associated with an object that can be dropped, such as streaming jobs, fragments, actors, batch tasks, etc.

When a set labels is dropped, it will record it in the uncollected_removed_labels set. Once the metrics has been collected, it will finally remove the metrics of the labels.

See also LabelGuardedMetricsInfo and LabelGuard::drop.

Arguments

• T - The type of the raw metrics vec.
• N - The number of labels.

Fields

inner: MetricVec<T>

info: Arc<Mutex<LabelGuardedMetricsInfo<N>>>

labels: [&'static str; N]

Implementations

impl<T: MetricVecBuilder, const N: usize> LabelGuardedMetricVec<T, N>

pub fn new(inner: MetricVec<T>, labels: &[&'static str; N]) -> Self

pub fn with_guarded_label_values( &self, labels: &[&str; N], ) -> LabelGuardedMetric<T::M, N>

This is similar to the with_label_values of the raw metrics vec. We need to pay special attention that, unless for some special purpose, we should not drop the returned LabelGuardedMetric immediately after using it, such as metrics.with_guarded_label_values(...).inc();, because after dropped the label will be regarded as not used any more, and the internal raw metrics will be removed and reset.

Instead, we should store the returned LabelGuardedMetric in a scope with longer lifetime so that the labels can be regarded as being used in its whole life scope. This is also the recommended way to use the raw metrics vec.

pub fn with_test_label(&self) -> LabelGuardedMetric<T::M, N>

impl<const N: usize> LabelGuardedMetricVec<impl MetricVecBuilder<M = GenericCounter<AtomicU64>>, N>

pub fn test_int_counter_vec() -> Self

impl<const N: usize> LabelGuardedMetricVec<impl MetricVecBuilder<M = GenericGauge<AtomicI64>>, N>

pub fn test_int_gauge_vec() -> Self

impl<const N: usize> LabelGuardedMetricVec<impl MetricVecBuilder<M = GenericGauge<AtomicF64>>, N>

pub fn test_gauge_vec() -> Self

impl<const N: usize> LabelGuardedMetricVec<impl MetricVecBuilder<M = Histogram>, N>

pub fn test_histogram_vec() -> Self

Trait Implementations

impl<T: Clone + MetricVecBuilder, const N: usize> Clone for LabelGuardedMetricVec<T, N>

fn clone(&self) -> LabelGuardedMetricVec<T, N>

Returns a copy of the value.

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

Performs copy-assignment from source.

impl<T: MetricVecBuilder, const N: usize> Collector for LabelGuardedMetricVec<T, N>

fn desc(&self) -> Vec<&Desc>

Return descriptors for metrics.

fn collect(&self) -> Vec<MetricFamily>

Collect metrics.

impl<T: MetricVecBuilder, const N: usize> Debug for LabelGuardedMetricVec<T, N>

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

Formats the value using the given formatter.