feat(cmd/example_server): Add simple prometheus metrics

sikalabs · May 14, 2023 · 1afb4cb · 1afb4cb
1 parent c83ccf1
commit 1afb4cb
Showing 1 changed file with 24 additions and 0 deletions.
diff --git a/cmd/example_server/example_server.go b/cmd/example_server/example_server.go
@@ -7,6 +7,8 @@ import (
 	"strconv"
 	"time"
 
+	"github.com/prometheus/client_golang/prometheus"
+	"github.com/prometheus/client_golang/prometheus/promhttp"
 	"github.com/sikalabs/slu/cmd/root"
 	"github.com/sikalabs/slu/version"
 	"github.com/spf13/cobra"
@@ -19,39 +21,61 @@ var Cmd = &cobra.Command{
 	Short: "Run example web server",
 	Args:  cobra.NoArgs,
 	Run: func(c *cobra.Command, args []string) {
+		var (
+			requestsTotal = prometheus.NewCounter(
+				prometheus.CounterOpts{
+					Name: "example_requests_total",
+					Help: "Total number of requests received.",
+				},
+			)
+		)
+
+		prometheus.MustRegister(requestsTotal)
+
 		portStr := strconv.Itoa(FlagPort)
 		hostname, _ := os.Hostname()
 		http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
+			requestsTotal.Inc()
 			fmt.Fprintf(w, "[slu "+version.Version+"] Example HTTP Server! %s %s \n", hostname, portStr)
 		})
 		http.HandleFunc("/slow1s", func(w http.ResponseWriter, r *http.Request) {
+			requestsTotal.Inc()
 			time.Sleep(1 * time.Second)
 			fmt.Fprintf(w, "[slu "+version.Version+"] Example HTTP Server (after 1s)! %s %s \n", hostname, portStr)
 		})
 		http.HandleFunc("/slow10s", func(w http.ResponseWriter, r *http.Request) {
+			requestsTotal.Inc()
 			time.Sleep(10 * time.Second)
 			fmt.Fprintf(w, "[slu "+version.Version+"] Example HTTP Server (after 10s)! %s %s \n", hostname, portStr)
 		})
 		http.HandleFunc("/slow30s", func(w http.ResponseWriter, r *http.Request) {
+			requestsTotal.Inc()
 			time.Sleep(30 * time.Second)
 			fmt.Fprintf(w, "[slu "+version.Version+"] Example HTTP Server (after 30s)! %s %s \n", hostname, portStr)
 		})
 		http.HandleFunc("/slow60s", func(w http.ResponseWriter, r *http.Request) {
+			requestsTotal.Inc()
 			time.Sleep(60 * time.Second)
 			fmt.Fprintf(w, "[slu "+version.Version+"] Example HTTP Server (after 60s)! %s %s \n", hostname, portStr)
 		})
 		http.HandleFunc("/slow5m", func(w http.ResponseWriter, r *http.Request) {
+			requestsTotal.Inc()
 			time.Sleep(5 * time.Minute)
 			fmt.Fprintf(w, "[slu "+version.Version+"] Example HTTP Server (after 5m)! %s %s \n", hostname, portStr)
 		})
 		http.HandleFunc("/slow10m", func(w http.ResponseWriter, r *http.Request) {
+			requestsTotal.Inc()
 			time.Sleep(10 * time.Minute)
 			fmt.Fprintf(w, "[slu "+version.Version+"] Example HTTP Server (after 10m)! %s %s \n", hostname, portStr)
 		})
 		http.HandleFunc("/slow15m", func(w http.ResponseWriter, r *http.Request) {
+			requestsTotal.Inc()
 			time.Sleep(15 * time.Minute)
 			fmt.Fprintf(w, "[slu "+version.Version+"] Example HTTP Server (after 15m)! %s %s \n", hostname, portStr)
 		})
+
+		http.Handle("/metrics", promhttp.Handler())
+
 		fmt.Println("[slu " + version.Version + "] Server started on 0.0.0.0:" + portStr + ", see http://127.0.0.1:" + portStr)
 		http.ListenAndServe(":"+portStr, nil)
 	},