prometheus metrics endpoint

llmproxymetrics.go

@@ -10,8 +10,12 @@ import (
 	"net/http/httputil"
 	"net/url"
 	"strconv"
+	"strings"
 
 	"github.com/caarlos0/env/v11"
+	"github.com/prometheus/client_golang/prometheus"
+	"github.com/prometheus/client_golang/prometheus/promauto"
+	"github.com/prometheus/client_golang/prometheus/promhttp"
 )
 
 var cfg config
@@ -23,12 +27,14 @@ type config struct {
 
 func createProxy(target *url.URL) func(http.ResponseWriter, *http.Request) {
 	return func(w http.ResponseWriter, r *http.Request) {
+		r.URL.Path = strings.TrimPrefix(r.URL.Path, "/proxy")
 		r.Host = target.Host
 		r.URL.Scheme = target.Scheme
 		r.URL.Host = target.Host
 
 		director := func(req *http.Request) {
 			req.Header.Set("X-Forwarded-For", r.RemoteAddr)
+			req.URL = r.URL
 			req.Host = target.Host
 			req.URL.Scheme = target.Scheme
 			req.URL.Host = target.Host
@@ -81,9 +87,15 @@ func handleJsonLine(line []byte) {
 	if jsonData["done"].(bool) {
 		duration := jsonData["eval_duration"].(float64)
 		fmt.Printf("Duration: %.2f seconds\n", duration/1000000000.0)
+		opsProcessed.Inc()
 	}
 }
 
+var opsProcessed = promauto.NewCounter(prometheus.CounterOpts{
+	Name: "total_requests",
+	Help: "The total number of processed events",
+})
+
 func main() {
 	err := env.Parse(&cfg)
 	if err != nil {
@@ -95,7 +107,8 @@ func main() {
 		log.Fatal(err)
 	}
 
-	http.HandleFunc("/", createProxy(targetURL))
+	http.HandleFunc("/proxy/", createProxy(targetURL))
+	http.Handle("/metrics", promhttp.Handler())
 
 	log.Printf("Starting proxy server on :%s", strconv.Itoa(cfg.Port))
 	err = http.ListenAndServe(fmt.Sprintf(":%d", cfg.Port), nil)