A bit of cleanup and documentation

http.go

@@ -22,11 +22,12 @@ func redirectRequest(w http.ResponseWriter, r *http.Request) {
 
 	ip := net.ParseIP(ipStr)
 
+	// TODO: This is temporary to allow testing on private addresses.
 	if ip.IsPrivate() {
 		ip = net.ParseIP("1.1.1.1")
 	}
 
-    server, distance, err := settings.Servers.Closest(ip)
+	server, distance, err := servers.Closest(ip)
 
 	if err != nil {
 		http.Error(w, err.Error(), http.StatusInternalServerError)

main.go

@@ -12,9 +12,10 @@ import (
 
 var (
 	db      *maxminddb.Reader
-    settings = &Settings{}
+	servers ServerList
 )
 
+// City represents a MaxmindDB city
 type City struct {
 	Location struct {
 		Latitude  float64 `maxminddb:"latitude"`
@@ -22,10 +23,6 @@ type City struct {
 	} `maxminddb:"location"`
 }
 
-type Settings struct {
-    Servers ServerList
-}
-
 func main() {
 	viper.SetConfigName("dlrouter")        // name of config file (without extension)
 	viper.SetConfigType("yaml")            // REQUIRED if the config file does not have the extension in the name
@@ -44,9 +41,9 @@ func main() {
 		log.WithError(err).Fatalln("Unable to open database")
 	}
 
-    servers := viper.GetStringSlice("servers")
+	serverList := viper.GetStringSlice("servers")
 
-    for _, server := range servers {
+	for _, server := range serverList {
 		var prefix string
 
 		if !strings.HasPrefix(server, "http") {
@@ -84,7 +81,7 @@ func main() {
 			continue
 		}
 
-        settings.Servers = append(settings.Servers, &Server{
+		servers = append(servers, &Server{
 			Host:      u.Host,
 			Path:      u.Path,
 			Latitude:  city.Location.Latitude,
@@ -101,10 +98,10 @@ func main() {
 
 	log.Info("Servers added, checking statuses")
 	// Force initial check before running
-    settings.Servers.Check()
+	servers.Check()
 
 	// Start check loop
-    go settings.Servers.checkLoop()
+	go servers.checkLoop()
 
 	log.Info("Starting")
 

middleware.go

@@ -13,6 +13,8 @@ var (
 	forwardLimit    = 5
 )
 
+// RealIPMiddleware is an implementation of reverse proxy checks.
+// It uses the remote address to find the originating IP, as well as protocol
 func RealIPMiddleware(f http.HandlerFunc) http.HandlerFunc {
 	return func(w http.ResponseWriter, r *http.Request) {
 		// Treat unix socket as 127.0.0.1
@@ -83,4 +85,3 @@ func realProto(r *http.Request) string {
 
 	return proto
 }
-

servers.go

@@ -31,12 +31,15 @@ func (s ServerList) checkLoop() {
 	t := time.NewTicker(60 * time.Second)
 
 	for {
-        <- t.C
+		<-t.C
 
 		s.Check()
 	}
 }
 
+// Check will request the index from all servers
+// If a server does not respond in 10 seconds, it is considered offline.
+// This will wait until all checks are complete.
 func (s ServerList) Check() {
 	var wg sync.WaitGroup
 
@@ -44,11 +47,13 @@ func (s ServerList) Check() {
 		wg.Add(1)
 
 		go func(server *Server) {
-            req, err := http.NewRequest(http.MethodGet, "https://" + server.Host + "/" + strings.TrimLeft(server.Path, "/"), nil)
+			req, err := http.NewRequest(http.MethodGet, "https://"+server.Host+"/"+strings.TrimLeft(server.Path, "/"), nil)
 
-            req.Header.Set("User-Agent", "ArmbianRouter/1.0 (Go " + runtime.Version() + ")")
+			req.Header.Set("User-Agent", "ArmbianRouter/1.0 (Go "+runtime.Version()+")")
 
 			if err != nil {
+				// This should never happen.
+				log.WithError(err).Warning("Invalid request! This should not happen, please check config.")
 				return
 			}
 
@@ -72,6 +77,8 @@ func (s ServerList) Check() {
 	wg.Wait()
 }
 
+// Closest will use GeoIP on the IP provided and find the closest server.
+// Return values are the closest server, the distance, and if an error occurred.
 func (s ServerList) Closest(ip net.IP) (*Server, float64, error) {
 	var city City
 	err := db.Lookup(ip, &city)