package main

import (
    "fmt"
    "net/http"
    "log"
)

var(
    metrics_num_urls int
)

func main() {
    log.Println("Starting HTTP listener")

    http.HandleFunc("/", httpHandler)
    http.HandleFunc("/metrics", metricsHandler)
    listenErr := http.ListenAndServe(":80", nil) // set listen port
    if listenErr != nil {
        log.Fatalln(listenErr.Error())
    }
}

// Handling incoming HTTP connections
func httpHandler(w http.ResponseWriter, r *http.Request) {
    metrics_num_urls++
    log.Printf("(%s) %s %s", r.Method, r.RemoteAddr, r.URL.Path)
}

// Handle HTTP /metrics requests
func metricsHandler(w http.ResponseWriter, req *http.Request) {
    fmt.Fprintf(w, "num_urls %d\n", metrics_num_urls)
}