Struct MetricsEncoder

pub struct MetricsEncoder<W: Write> { /* private fields */ }

MetricsEncoder provides methods to encode metrics in a text format that can be understood by Prometheus.

Metrics are encoded with the block time included, to allow Prometheus to discard out-of-order samples collected from replicas that are behind.

See Exposition Formats for an informal specification of the text format.

Implementations

impl<W: Write> MetricsEncoder<W>

pub fn new(writer: W, now_millis: i64) -> Self

Constructs a new encoder dumping metrics with the given timestamp into the specified writer.

pub fn into_inner(self) -> W

Returns the internal buffer that was used to record the metrics.

pub fn encode_histogram( &mut self, name: &str, buckets: impl Iterator<Item = (f64, f64)>, sum: f64, help: &str, ) -> Result<()>

Encodes the metadata and the value of a histogram.

SUM is the sum of all observed values, before they were put into buckets.

BUCKETS is a list (key, value) pairs, where KEY is the bucket and VALUE is the number of items in this bucket (i.e., it’s not a cumulative value).

pub fn histogram_vec<'a>( &'a mut self, name: &'a str, help: &'a str, ) -> Result<LabeledHistogramBuilder<'a, W>>

pub fn encode_single_value( &mut self, typ: &str, name: &str, value: f64, help: &str, ) -> Result<()>

pub fn encode_counter( &mut self, name: &str, value: f64, help: &str, ) -> Result<()>

Encodes the metadata and the value of a counter.

Panics

This function panics if the name argument does not match pattern [a-zA-Z_][a-zA-Z0-9_].

pub fn encode_gauge(&mut self, name: &str, value: f64, help: &str) -> Result<()>

Encodes the metadata and the value of a gauge.

Panics

This function panics if the name argument does not match pattern [a-zA-Z_][a-zA-Z0-9_].

pub fn counter_vec<'a>( &'a mut self, name: &'a str, help: &'a str, ) -> Result<LabeledMetricsBuilder<'a, W>>

Starts encoding of a counter that uses labels.

Panics

This function panics if the name argument does not match pattern [a-zA-Z_][a-zA-Z0-9_].

pub fn gauge_vec<'a>( &'a mut self, name: &'a str, help: &'a str, ) -> Result<LabeledMetricsBuilder<'a, W>>

Starts encoding of a gauge that uses labels.

Panics

This function panics if the name argument does not match pattern [a-zA-Z_][a-zA-Z0-9_].