@libp2p/prometheus-metrics
Version:
Collect libp2p metrics for scraping by Prometheus or Graphana
54 lines (45 loc) • 1.65 kB
text/typescript
import { Histogram as PromHistogram } from 'prom-client'
import { normalizeString } from './utils.js'
import type { PrometheusCalculatedHistogramOptions } from './index.js'
import type { HistogramGroup, StopTimer } from '@libp2p/interface'
import type { CollectFunction } from 'prom-client'
export class PrometheusHistogramGroup implements HistogramGroup {
private readonly histogram: PromHistogram
private readonly label: string
constructor (name: string, opts: PrometheusCalculatedHistogramOptions<Record<string, number>>) {
name = normalizeString(name)
const help = normalizeString(opts.help ?? name)
const label = this.label = normalizeString(opts.label ?? name)
let collect: CollectFunction<PromHistogram<any>> | undefined
// calculated metric
if (opts?.calculate != null) {
collect = async function () {
const values = await opts.calculate()
Object.entries(values).forEach(([key, value]) => {
this.observe({ [label]: key }, value)
})
}
}
this.histogram = new PromHistogram({
name,
help,
buckets: opts.buckets ?? [0.005, 0.01, 0.025, 0.05, 0.1, 0.25, 0.5, 1, 2.5, 5, 10],
labelNames: [this.label],
registers: opts.registry !== undefined ? [opts.registry] : undefined,
collect
})
}
observe (values: Record<string, number>): void {
Object.entries(values).forEach(([key, value]) => {
this.histogram.observe({ [this.label]: key }, value)
})
}
reset (): void {
this.histogram.reset()
}
timer (key: string): StopTimer {
return this.histogram.startTimer({
[key]: 0
})
}
}