How to integrate logging with monitoring and alerting systems (e.g., Prometheus) in Go?

To integrate logging with monitoring and alerting systems like Prometheus in Go, you can follow these steps:

Import the necessary packages:

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

Initialize and configure your logger:

log := log.New(os.Stdout, "[MyApp] ", log.LstdFlags)

Create and register Prometheus metrics:

requestsTotal := prometheus.NewCounter(prometheus.CounterOpts{
	Name: "myapp_requests_total",
	Help: "Total number of requests",
})

prometheus.MustRegister(requestsTotal)

Add a middleware to your HTTP handler to instrument requests:

func instrument(handler http.Handler) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		requestsTotal.Inc()
		handler.ServeHTTP(w, r)
	})
}

Create an HTTP handler to expose the Prometheus metrics:

http.Handle("/metrics", promhttp.Handler())

Wrap your existing HTTP handler with the instrumentation middleware:

http.Handle("/", instrument(myHandler))

Start the HTTP server:

log.Println("Starting server on port 8080...")
if err := http.ListenAndServe(":8080", nil); err != nil {
	log.Fatal(err)
}

Now, when your application receives HTTP requests, Prometheus will collect metrics about the requests. You can then use Prometheus to visualize the collected data and set up alerts based on defined thresholds.

Remember to import and install the necessary Prometheus dependencies (github.com/prometheus/client_golang/prometheus and github.com/prometheus/client_golang/prometheus/promhttp) if you have not done so already.