@zcong/koa-prometheus NPM

koa-prometheus

koa prometheus middleware

Install

$ yarn add @zcong/koa-prometheus
# npm
$ npm i @zcong/koa-prometheus --save

Usage

import * as Koa from 'koa'
import { setupProm } from '@zcong/koa-prometheus'

const app = new Koa()

setupProm(app) // use default config

default metrics route is /metrics.

Config

use custom config

setupProm(app, {
  // custom config here
})

name	description	default	example
metricsPath	export metrics route	/metrics	/custom/route
collectDefaultMetrics	if collect default metrics	true	false
defaultLabels	global labels	{}	{ app: 'myApp' }
statusNormalizer	func for normalizing status code	config.ts
requestDurationUseHistogram	if requestDuration use Histogram or Summary	true	false

Prometheus query examples

QPS over the last 5m

sum(rate(http_requests_total{job=~"__your_job__", route=~".*"}[5m])) by (route)

Avarage request durations in ms over the last 5m

avg(increase(http_request_duration_ms_sum{job=~"__your_job__", route=~".*"}[5m])/ increase(http_request_duration_ms_count{job=~"__your_job__", route=~".*"}[5m]) >0) by (route)

Non 200 status rate over the last 5m

sum(irate(http_requests_total{status!~"200",job=~"__your_job__", route=~".*"}[5m])) BY (job, route, status) / IGNORING(status) GROUP_LEFT() sum(irate(http_requests_total{job=~"__your_job__", route=~".*"}[5m])) BY (job, route) * 100