Adds power exporter

cmd/export/httpServer.go

@@ -0,0 +1,72 @@
+package main
+
+import (
+	"fmt"
+	"log"
+	"strings"
+	"time"
+
+	"net/http"
+
+	"github.com/prometheus/client_golang/prometheus/promhttp"
+)
+
+func httpAccessLog(req *http.Request) {
+	log.Printf("[TRACE] %s - %s - %s\n", req.Method, req.RemoteAddr, req.RequestURI)
+}
+
+func crossSiteOrigin(w http.ResponseWriter) {
+	w.Header().Add("Access-Control-Allow-Origin", "*")
+	w.Header().Add("Access-Control-Allow-Methods", "POST, GET, OPTIONS")
+}
+
+func (config *config) httpServer() {
+	path := http.NewServeMux()
+
+	connection := &http.Server{
+		Addr:         fmt.Sprintf("%s:%d", config.WebSrvIP, config.WebSrvPort),
+		Handler:      path,
+		ReadTimeout:  time.Duration(config.WebSrvReadTimeout) * time.Second,
+		WriteTimeout: time.Duration(config.WebSrvWriteTimeout) * time.Second,
+		IdleTimeout:  time.Duration(config.WebSrvIdleTimeout) * time.Second,
+	}
+
+	// metrics
+	path.HandleFunc("/metrics", func(w http.ResponseWriter, r *http.Request) {
+		httpAccessLog(r)
+		crossSiteOrigin(w)
+		promhttp.Handler().ServeHTTP(w, r)
+	})
+	// healthcheck
+	path.HandleFunc("/healthcheck", webHealthCheck)
+	// root
+	path.HandleFunc("/", webRoot)
+
+	if err := connection.ListenAndServe(); err != nil {
+		log.Fatalf("[ERROR] %s\n", err)
+	}
+}
+
+func webRoot(w http.ResponseWriter, r *http.Request) {
+	httpAccessLog(r)
+	crossSiteOrigin(w)
+
+	if strings.ToLower(r.Method) == "get" {
+		tmpltWebRoot(w)
+	} else {
+		log.Printf("[DEBUG] Request to '/' was made using the wrong method: expected %s, got %s\n", "GET", strings.ToUpper(r.Method))
+		tmpltError(w, http.StatusBadRequest, "Invalid http method.")
+	}
+}
+
+func webHealthCheck(w http.ResponseWriter, r *http.Request) {
+	httpAccessLog(r)
+	crossSiteOrigin(w)
+
+	if strings.ToLower(r.Method) == "get" {
+		tmpltHealthCheck(w)
+	} else {
+		log.Printf("[DEBUG] Request to '/healthcheck' was made using the wrong method: expected %s, got %s\n", "GET", strings.ToUpper(r.Method))
+		tmpltError(w, http.StatusBadRequest, "Invalid http method.")
+	}
+}