fix : backend to interface

backend/backend.go

@@ -1,40 +1,55 @@
 package backend
 
-import "sync"
+import (
+	"net/http"
+	"sync"
+)
 
-type Backend struct {
+type Backend interface {
+	SetDead(bool)
+	GetIsDead() bool
+	GetConnections() int
+	GetURL() string
+	Serve(http.ResponseWriter, *http.Request)
+}
+
+type backend struct {
 	URL         string `json:"url"`
 	IsDead      bool
 	mu          sync.RWMutex
 	connections int
 }
 
-func (backend *Backend) SetDead(b bool) {
+func (backend *backend) SetDead(b bool) {
 	backend.mu.Lock()
 	backend.IsDead = b
 	backend.mu.Unlock()
 }
 
-func (backend *Backend) GetIsDead() bool {
+func (backend *backend) GetIsDead() bool {
 	backend.mu.RLock()
 	isAlive := backend.IsDead
 	backend.mu.RUnlock()
 	return isAlive
 }
 
-func (backend *Backend) GetConnections() int {
+func (backend *backend) GetConnections() int {
 	return backend.connections
 }
 
-func NewBackend(url string) Backend {
-	return Backend{
+func (backend *backend) GetURL() string {
+	return backend.URL
+}
+
+func NewBackend(url string) backend {
+	return backend{
 		URL:    url,
 		IsDead: false,
 	}
 }
 
-func NewDefaultBackend() []Backend {
-	return []Backend{
+func NewDefaultBackend() []backend {
+	return []backend{
 		{
 			URL:    "http://localhost:8081/",
 			IsDead: false,

handler.go

@@ -0,0 +1,20 @@
+package main
+
+import "net/http"
+
+type LBHandler interface {
+	Serve(http.ResponseWriter, *http.Request)
+}
+
+type lbHandler struct {
+	serverPool ServerPool
+}
+
+func (lb *lbHandler) Serve(w http.ResponseWriter, r *http.Request) {
+	peer := lb.serverPool.GetNextValidPeer()
+	if peer != nil {
+		peer.Serve(w, r)
+		return
+	}
+	http.Error(w, "Service not available", http.StatusServiceUnavailable)
+}

health.go

@@ -26,7 +26,7 @@ func healthCheck(ctx context.Context, sv ServerPool) {
 			bcd := sv.GetBackends()
 			for _, b := range bcd {
 				b := b
-				pingURL, err := url.Parse(b.URL)
+				pingURL, err := url.Parse(b.GetURL())
 				if err != nil {
 					log.Fatal(err.Error())
 				}
@@ -36,7 +36,7 @@ func healthCheck(ctx context.Context, sv ServerPool) {
 				if !isAlive {
 					msg = "dead"
 				}
-				log.Printf("%v checked %v by healthcheck", b.URL, msg)
+				log.Printf("%v checked %v by healthcheck", b.GetURL(), msg)
 			}
 		case <-ctx.Done():
 			return

lc/serverpool.go

@@ -31,6 +31,20 @@ func (s *lcserverPool) GetNextValidPeer() backend.Backend {
 	return leastConnectedPeer
 }
 
+func (s *lcserverPool) GetBackends() []backend.Backend {
+	return s.Backends
+}
+
+func (s *lcserverPool) AddBackend(b backend.Backend) {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	s.Backends = append(s.Backends, b)
+}
+
+func (s *lcserverPool) GetServerPoolSize() int {
+	return len(s.Backends)
+}
+
 func NewlcserverPool(backends []backend.Backend) lcserverPool {
 	return lcserverPool{
 		Backends: backends,

main.go

@@ -4,8 +4,6 @@ import (
 	"context"
 	"log"
 	"net/http"
-
-	"github.com/seipan/mylb/lc"
 )
 
 // Serve serves a loadbalancer.
@@ -14,7 +12,7 @@ func main() {
 
 	s := http.Server{
 		Addr:    ":" + "8080",
-		Handler: http.HandlerFunc(lc.LcHandler),
+		Handler: http.HandlerFunc(nil),
 	}
 	if err := s.ListenAndServe(); err != nil {
 		log.Fatal(err.Error())