Add prometheus metrics

main.go

@@ -4,11 +4,15 @@ import (
 	"encoding/json"
 	"fmt"
 	"log"
+	"math/rand"
 	"net/http"
 	"os"
+
+	"github.com/prometheus/client_golang/prometheus/promhttp"
+	"mcquay.me/metrics"
 )
 
-const version = "v0.0.11"
+const version = "v0.1.0"
 
 type v struct {
 	Hostname string `json:"hostname"`
@@ -16,11 +20,15 @@ type v struct {
 }
 
 func main() {
+	m, err := metrics.New("hw")
+	if err != nil {
+		log.Fatalf("metrics: %v", err)
+	}
 	hn, err := os.Hostname()
 	if err != nil {
 		log.Fatalf("hostname: %+v", err)
 	}
-	http.HandleFunc("/", func(w http.ResponseWriter, req *http.Request) {
+	http.HandleFunc("/", m.WrapFunc("/", func(w http.ResponseWriter, req *http.Request) {
 		w.Header().Set("Content-Type", "application/json")
 		r := v{
 			Hostname: hn,
@@ -29,14 +37,25 @@ func main() {
 		if err := json.NewEncoder(w).Encode(r); err != nil {
 			log.Printf("json: %+v", err)
 		}
-	})
-	http.HandleFunc("/env", func(w http.ResponseWriter, req *http.Request) {
+	}))
+	http.HandleFunc("/env", m.WrapFunc("/env", func(w http.ResponseWriter, req *http.Request) {
 		for _, line := range os.Environ() {
 			fmt.Fprintf(w, "%v\n", line)
 		}
-	})
-	http.HandleFunc("/live", ok)
-	http.HandleFunc("/ready", ok)
+	}))
+
+	codes := []int{
+		http.StatusBadGateway,
+		http.StatusBadRequest,
+		http.StatusUnauthorized,
+	}
+	http.HandleFunc("/bad", m.WrapFunc("/bad", func(w http.ResponseWriter, req *http.Request) {
+		code := codes[rand.Intn(len(codes))]
+		w.WriteHeader(code)
+	}))
+	http.HandleFunc("/live", m.WrapFunc("/live", ok))
+	http.HandleFunc("/ready", m.WrapFunc("/ready", ok))
+	http.Handle("/metrics", promhttp.Handler())
 	if err := http.ListenAndServe(":8080", nil); err != nil {
 		log.Fatalf("listen and serve: %v", err)
 	}