@stackbox/fastify-metrics NPM

fastify-metrics

Prometheus metrics exporter for Fastify.

This plugin uses prom-client under the hood.

This plugin also adds 2 http metrics for your routes:

Requests duration histogram
Requests duration summary

Fastify support

v3.x.x - supports fastify-1.x
v4.x.x - supports fastify-2.x prom-client-11.x
v5.x.x - supports fastify-2.x prom-client-12.x
v6.x.x - supports fastify-3.x

Notable changes

v6.x.x

Fastify v3 support.
Drop node.js 8 support.
enableDefaultMetrics - now enables only default prom-client metrics. Set to true by default.
enableRouteMetrics - additional flag that enables route metrics. Set to true by default.

Installation

npm i fastify-metrics --save

Features and requirements

Collects default server metrics (see prom-client);
Collects route response timings
Adds metrics to fastify instance for your custom metrics.

Requires fastify >=3.0.0.
Node.js >=10.0.0.

Usage

Add it to your project like regular fastify plugin. Use register method and pass options to it.

const fastify = require('fastify');
const app = fastify();

const metricsPlugin = require('fastify-metrics');
app.register(metricsPlugin, { endpoint: '/metrics' });

It also exports client to fastify instance fastify.metrics.client which you may use it in your routes.

You may create your metrics when app starts and store it in fastify.metrics object and reuse them in multiple routes.

Plugin options

parameter	type	description	default
`enableDefaultMetrics`	Boolean	Enables collection of default prom-client metrics.	`true`
`enableRouteMetrics`	Boolean	Enables collection of fastify route metrics.	`true`
`pluginName`	String	Change name which you'll use to access prometheus client instance in fastify.	`metrics`
`interval`	Number	Default metrics collection interval in ms.	`5000`
`register`	Object	Custom prom-client metrics registry.	`undefined`
`prefix`	String	Custom default metrics prefix.	`""`
`endpoint`	String	If set, fastify route will be added to expose metrics. If not set you may manually add it afterwards.	`undefined`
`metrics`	Object	Allows override default metrics config. See section below.	`{}`
`blacklist`	String, RegExp, String[]	Skip metrics collection for blacklisted routes	`undefined`
`groupStatusCodes`	Boolean	Groups status codes (e.g. 2XX) if `true`	`false`

Metrics details

You may override default metrics settings. You may provide overrides for two metrics tracking http request durations: histogram and summary. Default values:

{
  histogram: {
    name: 'http_request_duration_seconds',
    help: 'request duration in seconds',
    labelNames: ['status', 'method', 'route'],
    buckets: [0.05, 0.1, 0.5, 1, 3, 5, 10],
  },
  summary: {
    name: 'http_request_summary_seconds',
    help: 'request duration in seconds summary',
    labelNames: ['status', 'method', 'route'],
    percentiles: [0.5, 0.9, 0.95, 0.99],
  },
}

You may also provide registers there or use it instead of prefix. Override should look like:

const fastify = require('fastify');
const app = fastify();
const metricsPlugin = require('fastify-metrics');

app.register(metricsPlugin, {endpoint: '/metrics', {
  histogram: {
    name: 'my_custom_http_request_duration_seconds',
    buckets: [0.1, 0.5, 1, 3, 5],
  },
  summary: {
    help: 'custom request duration in seconds summary help',
    labelNames: ['status', 'method', 'route'],
    percentiles: [0.5, 0.75, 0.9, 0.95, 0.99],
  },
}});

HTTP routes metrics

The following table shows what metrics will be available in Prometheus. Note suffixes like _bucket, _sum, _count are added automatically.

metric	labels	description
`http_request_duration_seconds_count`	`method`, `route`, `status`	Requests total count
`http_request_duration_seconds_bucket`	`method`, `route`, `status`	Requests durations by bucket
`http_request_duration_seconds_sum`	`method`, `route`, `status`	Requests duration summaries by quantile

Docs

See docs.

Changelog

See changelog.

License

Licensed under MIT.

fastify-plugin metrics prometheus fastify plugin

fastify-plugin prom-client

6.0.3

4 years ago

@stackbox/fastify-metrics v6.0.3