metrics/metrics.v

module metrics

import io

[params]
pub struct Metric {
	name   string      [required]
	labels [][2]string
}

[inline]
fn join_two_array(arr [2]string) string {
	return '${arr[0]}="${arr[1]}"'
}

pub fn (m &Metric) str() string {
	if m.labels.len == 0 {
		return m.name
	}

	return '$m.name{${m.labels.map(join_two_array(it)).join(',')}}'
}

pub interface MetricsCollector {
	counter_get(metric Metric) ?u64
	counters() []Metric
	histogram_get(metric Metric) ?[]f64
	histograms() []Metric
	gauge_get(metric Metric) ?f64
	gauges() []Metric
mut:
	counter_set(val u64, metric Metric)
	counter_increment(metric Metric)
	histogram_record(value f64, metric Metric)
	gauge_set(value f64, metric Metric)
	gauge_add(value f64, metric Metric)
	gauge_sub(value f64, metric Metric)
}

pub interface MetricsExporter {
	load(collector MetricsCollector)
	export_to_writer(writer io.Writer) !
	export_to_string() !string
}