How can I implement Prometheus metrics in a Go application?

How can I implement Prometheus metrics in a Go application?

To implement Prometheus metrics in a Go application, you can use the Prometheus Go client library. First, install it using go get github.com/prometheus/client_golang/prometheus. Then, define your metrics, register them, and expose them via an HTTP endpoint.

What types of metrics can I track with Prometheus?

You can track various types of metrics such as counters, gauges, histograms, and summaries. Counters are for counting events, gauges for measuring values, histograms for tracking distributions, and summaries for quantiles.

How do I expose the metrics endpoint in my Go application?

You can expose the metrics endpoint by creating an HTTP handler. Use http.HandleFunc to set up a route for /metrics, and call prometheus.Handler() to serve the metrics.

Can you show me a code example?

Sure! 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"},
    )
)

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

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

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

This code sets up a basic HTTP server that tracks the number of requests.