Gin Prometheus Metrics Middleware

This repository provides a Gin middleware to collect Prometheus metrics for your Gin-based applications. The middleware captures HTTP request data, including response time, request counts, and more, and exposes them in a format that Prometheus can scrape.

Features

• Collects HTTP request count by method, status, and endpoint
• Tracks response time (latency) for each endpoint
• Collects request size and response size
• Provides a /metrics endpoint for Prometheus to scrape
• Easy integration with existing Gin applications

Installation

Install the middleware using go get:

go get github.com/logocomune/gin-prometheus

Usage

Here’s how to integrate the middleware into your Gin application:

package main

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

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

	r.Use(ginprom.Middleware())

	r.GET("/metrics", gin.WrapH(ginprom.GetMetricHandler()))

	r.GET("/", func(c *gin.Context) {
		c.String(200, "Hello World")
	})
	r.GET("/test/:id", func(c *gin.Context) {
		c.String(200, "Hello World")
	})
	r.GET("/ping", func(c *gin.Context) {
		c.JSON(200, gin.H{
			"message": "pong",
		})
	})
	r.Run() // listen and serve on 0.0.0.0:8080
}

Middleware Options

The Middleware function allows you to customize the behavior of the middleware by passing configuration options:

metricsMiddleware := ginprometheus.Middleware(
ginprometheus.WithRecordRequests(false),
)

Metrics Collected

The middleware collects the following metrics:

1. HTTP Request Count

   • Metric name: http_requests_total
   • Labels: method, status, path`

2. HTTP Request Duration

   • Metric name: http_request_duration_seconds
   • Labels: method, status, path

3. Request Size

   • Metric name: http_request_size_bytes
   • Labels: method, status, path

4. Response Size

   • Metric name: http_response_size_bytes
   • Labels:method, status, path

Contributing

Contributions are welcome! Please open an issue or submit a pull request if you’d like to improve this middleware.

License

This project is licensed under the MIT License.