go-gin-prometheus

Gin Web Framework Prometheus metrics exporter

Installation

$ go get github.com/banzaicloud/go-gin-prometheus

Usage

package main

import (
	"github.com/gin-gonic/gin"
	"github.com/banzaicloud/go-gin-prometheus"
)

func main() {
	r := gin.New()

	p := ginprometheus.NewPrometheus("gin", []string{})
	p.SetListenAddress(":9900")
	p.Use(r, "/metrics")

	r.GET("/", func(c *gin.Context) {
		c.JSON(200, "Hello world!")
	})

	r.Run(":29090")
}

Preserving a low cardinality for the request counter

The request counter (requests_total) has a url label which, although desirable, can become problematic in cases where your application uses templated routes expecting a great number of variations, as Prometheus explicitly recommends against metrics having high cardinality dimensions:

https://prometheus.io/docs/practices/naming/#labels

If you have for instance a /customer/:name templated route and you want to generate a time series for every possible customer name:

package main

import (
	"github.com/gin-gonic/gin"
	"github.com/banzaicloud/go-gin-prometheus"
)

func main() {
	r := gin.New()

	p := ginprometheus.NewPrometheus("gin", []string{"name"})
	p.SetListenAddress(":9900")
	p.Use(r, "/metrics")

	r.GET("/", func(c *gin.Context) {
		c.JSON(200, "Hello world!")
	})

	r.Run(":29090")
}