Can you show me examples of using the Go metrics library?

Can you show me examples of using the Go metrics library?

Sure! The Go metrics library is great for tracking application performance. Would you like to see examples for HTTP requests or custom metrics?

Let's start with HTTP requests.

Alright! You can use the prometheus package to track HTTP request metrics. Here's a simple example:

package main

import (
    "net/http"
    "github.com/prometheus/client_golang/prometheus"
    "github.com/prometheus/client_golang/prometheus/promhttp"
)

var (
    requestCount = prometheus.NewCounterVec(
        prometheus.CounterOpts{
            Name: "http_requests_total",
            Help: "Total number of HTTP requests.",
        },
        []string{"method", "endpoint"},
    )
)

func init() {
    prometheus.MustRegister(requestCount)
}

func handler(w http.ResponseWriter, r *http.Request) {
    requestCount.WithLabelValues(r.Method, r.URL.Path).Inc()
    w.Write([]byte("Hello, World!"))
}

func main() {
    http.HandleFunc("/", handler)
    http.Handle("/metrics", promhttp.Handler())
    http.ListenAndServe(":8080", nil)
}

This code tracks the total number of HTTP requests by method and endpoint.

That looks great! Can you explain how to visualize these metrics?

Certainly! You can visualize these metrics using Grafana. First, set up Prometheus to scrape your application's /metrics endpoint. Then, in Grafana, create a new dashboard and add a graph panel. Use the query http_requests_total to visualize the request counts over time.