minor changes, adding port flag

Author: SamSyntax

loadbalancer.go

@@ -27,6 +27,16 @@ func (s LbServer) Address() string {
 }
 
 func (s LbServer) IsAlive() bool {
+	res, err := http.Get(s.addr)
+	if err != nil {
+		fmt.Printf("Server %s - addr: %s is currently offline\n", s.name, s.addr)
+		return false
+	}
+	if res.StatusCode != http.StatusOK {
+		fmt.Printf("Server %s - addr: %s is currently offline\n", s.name, s.addr)
+		return false
+	}
+	fmt.Printf("Server %s - addr: %s is online\n", s.name, s.addr)
 	return true
 }
 
@@ -74,7 +84,7 @@ func (lb *LoadBalancer) getWeightedServer() LbServer {
 	totalServers := len(lb.servers)
 	for i := 0; i < totalServers; i++ {
 		server := &lb.servers[lb.roundRobinCount%totalServers]
-		if server.current < server.weight {
+		if server.current < server.weight && server.IsAlive() {
 			server.current++
 			return *server
 		}

loader.go

@@ -58,7 +58,7 @@ func ReadJson(path string) []LbServer {
 	for k, s := range servers {
 		lbServer := NewLbServer(s.Addr, s.Weight)
 		lbServer.name = strconv.Itoa(k)
-		res = append(res, *lbServer)
+    res = append(res, *lbServer)
 	}
 
 	return res
@@ -84,7 +84,7 @@ func ReadYaml(path string) []LbServer {
 	for k, s := range servers {
 		lbServer := NewLbServer(s.Addr, s.Weight)
 		lbServer.name = strconv.Itoa(k)
-		res = append(res, *lbServer)
+    res = append(res, *lbServer)
 	}
 
 	return res

main.go

@@ -8,36 +8,44 @@ import (
 )
 
 func main() {
-	nFlag := flag.Int("amount", 1234, "Enter amount of local servers to be spawned")
+
+	// creating flags to pass args
+	nFlag := flag.Int("amount", 5, "Enter amount of local servers to be spawned")
 	method := flag.String("method", "rr", "Load balancing method: 'rr - Round Robin | wrr - Weighted Round Robin")
 	env := flag.String("env", "local", "Specify wether local servers should be started or provide JSON file with addresses of external servers. ")
 	path := flag.String("path", "./servers.yaml", "Specify a path to servers config file. Either yaml or json. ")
+	Lbport := flag.String("port", "7000", "Specify port on which load balancer is launched.")
+	LocalServerPort := flag.Int("srv-port", 8000, "Specify port on which local dev server is launched. (If there are more than 1 server to be launched port number will be incremented by 1 for every local server to be spawned ex. server 0 - :8000; sever 1 - :8001)")
 
+	// parsing flags
 	flag.Parse()
+
 	var servers []LbServer
 	switch *env {
 	case "external":
 		servers = Loader(*path)
 	case "local":
-		servers = Spawner(*nFlag)
+		servers = Spawner(*nFlag, *LocalServerPort)
 	}
 	var lb *LoadBalancer
 	switch *method {
 	case "wrr":
-		lb = NewLoadBalancer("7000", servers, true)
+		lb = NewLoadBalancer(*Lbport, servers, true)
 	case "rr":
-		lb = NewLoadBalancer("7000", servers, false)
+		lb = NewLoadBalancer(*Lbport, servers, false)
 	default:
 		fmt.Println("Invalid method. Use 'rr' or 'wrr'.")
 		os.Exit(1)
 	}
+
 	handleRedirect := func(w http.ResponseWriter, r *http.Request) {
 		lb.ServeProxy(w, r)
 	}
-	http.HandleFunc("/", handleRedirect)
 
+	// Serving loadbalancer
+	http.HandleFunc("/", handleRedirect)
 	fmt.Printf("serving requests at localhost:%s\n", lb.port)
-
 	http.ListenAndServe(":"+lb.port, nil)
+
 	select {}
 }

servers.json

@@ -1,7 +1,7 @@
 [
   {
     "addr": "https://facebook.com",
-    "weight": 2
+    "weight": 2,
   },
   {
     "addr": "https://twitch.tv",

servers.yaml

@@ -1,7 +1,7 @@
 ---
 - addr: https://facebook.com
   weight: 2
-- addr: https://twitch.tv
+- addr: https://twitch22t.tv
   weight: 1
 - addr: https://google.com
   weight: 3

spawner.go

@@ -32,7 +32,7 @@ func Server(port, name string, weight int) LbServer {
 	return *srv
 
 }
-func Spawner(amt int) []LbServer {
+func Spawner(amt, port int) []LbServer {
 	servers := make([]LbServer, 0, amt)
 	weights := []int{5, 2, 3}
 	for i := 0; i < amt; i++ {
@@ -41,10 +41,15 @@ func Spawner(amt int) []LbServer {
 			k = 0
 		}
 		k++
-		name := fmt.Sprintf("Server %v", i)
-		port := ":" + strconv.Itoa(8000+i)
+		name := fmt.Sprintf("Server %v", i+1)
+		port := ":" + strconv.Itoa(port+i)
 		srv := Server(port, name, weights[k])
-		servers = append(servers, srv)
+		if srv.IsAlive() {
+			servers = append(servers, srv)
+		} else {
+			continue
+		}
+
 	}
 	return servers
 }