Add handler for version information

main.go

@@ -41,6 +41,7 @@ func main() {
 	prometheus.MustRegister(metrics)
 
 	http.Handle("/metrics", promhttp.HandlerFor(prometheus.DefaultGatherer, promhttp.HandlerOpts{}))
+	http.Handle("/version", versionHandler(log))
 	http.Handle("/", http.RedirectHandler("/metrics", http.StatusFound))
 
 	log.Infof("Listen on %s...", cfg.Addr)

version.go

@@ -0,0 +1,33 @@
+package main
+
+import (
+	"encoding/json"
+	"net/http"
+
+	"github.com/sirupsen/logrus"
+)
+
+var (
+	// Version contains the version as set during the build.
+	Version = ""
+
+	// GitCommit contains the git commit hash set during the build.
+	GitCommit = ""
+)
+
+func versionHandler(log logrus.FieldLogger) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		info := struct {
+			Version string `json:"version"`
+			Commit  string `json:"commit"`
+		}{
+			Version: Version,
+			Commit:  GitCommit,
+		}
+
+		w.Header().Add("Content-Type", "application/json")
+		if err := json.NewEncoder(w).Encode(info); err != nil {
+			log.Errorf("Error encoding version info: %s", err)
+		}
+	})
+}