Adjust backend monitor

internal/backend/backend.go

@@ -13,7 +13,7 @@ type Backends map[string][]*Backend
 
 type Backend struct {
 	Name    string
-	Url     string
+	URL     *url.URL
 	Proxy   *httputil.ReverseProxy
 	Live    bool
 	Monitor []MonitorFrame
@@ -51,12 +51,15 @@ func CreateBackends(nameUrlPairs string) (Backends, error) {
 			k := split[i-1]
 			_, ok := backends[k]
 			backendUrl := split[i]
-			b, _ := createBackend(k, backendUrl)
+			b, err := createBackend(k, backendUrl)
+			if err != nil {
+				return nil, err
+			}
 			if !ok {
 				backends[k] = []*Backend{b}
 			} else {
 				for _, existingBackend := range backends[k] {
-					if existingBackend.Url == backendUrl {
+					if existingBackend.URL.Host == b.URL.Host {
 						return nil, fmt.Errorf("url (%s) already exist in backend (%s)", backendUrl, k)
 					}
 				}
@@ -74,12 +77,15 @@ func createBackend(key, urlString string) (*Backend, error) {
 	if err != nil {
 		return nil, err
 	}
+	if urlParsed.Host == "" {
+		return nil, fmt.Errorf("empty host for url (%s) in backend (%s)", urlString, key)
+	}
 
 	proxy := httputil.NewSingleHostReverseProxy(urlParsed)
 
 	return &Backend{
 		string(strip([]byte(fmt.Sprintf("%s%s", key, urlString)))),
-		urlString,
+		urlParsed,
 		proxy,
 		false,
 		[]MonitorFrame{},

internal/backend/backend_test.go

@@ -9,17 +9,19 @@ func TestCreateBackends(t *testing.T) {
 	var tests = []struct {
 		nameUrlPairs string
 		key          string
-		values       []Backend
+		host         string
 	}{
-		{"a,b", "a", []Backend{{Url: "b"}}},
+		{"a,http://b:1234", "a", "b:1234"},
 	}
 
 	for _, test := range tests {
-		result, _ := CreateBackends(test.nameUrlPairs)
-		for i, v := range result[test.key] {
-			if v.Url != test.values[i].Url {
-				t.Errorf("wrong backend url: want (%s) got (%s)\n", test.values[i].Url, v.Url)
-			}
+		be, err := CreateBackends(test.nameUrlPairs)
+		if err != nil {
+			t.Error(err)
+		}
+		b := be[test.key][0]
+		if b.URL.Host != test.host {
+			t.Errorf("wrong backend url: want (%s) got (%s)\n", test.host, b.URL.Host)
 		}
 	}
 }
@@ -34,17 +36,17 @@ func TestCreateBackendsErrors(t *testing.T) {
 		{"a,b,c", fmt.Errorf("backends must be a comma-separated list containing even number of items")},
 		{",", fmt.Errorf("nameUrlPair at index 0 must have a value")},
 		{"a,", fmt.Errorf("nameUrlPair at index 1 must have a value")},
-		{"a,b,a,b", fmt.Errorf("url (b) already exist in backend (a)")},
-		{"a,b", nil},
+		{"a,b,a,b", fmt.Errorf("empty host for url (b) in backend (a)")},
+		{"a,http://b:1234,a,http://b:1234", fmt.Errorf("url (http://b:1234) already exist in backend (a)")},
 	}
 
 	for _, test := range tests {
 		_, err := CreateBackends(test.nameUrlPairs)
-		if test.err != nil && err.Error() != test.err.Error() {
-			t.Errorf("Want: %s\nGot: %s\n", test.err.Error(), err.Error())
+		if err == nil {
+			t.Errorf("was expecting an error\n")
 		}
-		if test.err == nil && err != nil {
-			t.Errorf("Was not expecting an error\n")
+		if test.err != nil && err.Error() != test.err.Error() {
+			t.Errorf("was expecting an error: want (%s)\ngot: (%s)\n", test.err.Error(), err.Error())
 		}
 	}
 }

internal/backend/monitor.go

@@ -25,7 +25,7 @@ func (b Backends) Monitor() chan interface{} {
 
 func (be *Backend) monitor(messages chan interface{}) {
 	for {
-		latency := healthCheck(be.Url)
+		latency := healthCheck(be.URL.Host)
 		be.Live = latency > 0
 
 		colorCode := getColorCode(latency)

internal/backend/monitor_test.go

@@ -16,14 +16,14 @@ func TestHealthCheckBackend(t *testing.T) {
 	}
 	latency := healthCheck(url.Host)
 	if latency == 0 {
-		t.Errorf("latency should be greated then 0, got (%v)", latency)
+		t.Errorf("wrong latency: want (>0) got (%v)\n", latency)
 	}
 }
 
 func TestHealthCheckNoBackend(t *testing.T) {
 	latency := healthCheck("notexists.local:1234")
 	if latency > 0 {
-		t.Errorf("latency should be 0, got (%v)", latency)
+		t.Errorf("wrong latency: want (0) got (%v)\n", latency)
 	}
 }
 

internal/dashboard/templates/monitor.html

@@ -14,7 +14,7 @@
                 <div>
                     {{range $value}}
                     <div class="monitor" name="{{.Name}}">
-                        <div class="monitor-name">{{.Url}}</div>
+                        <div class="monitor-name">{{.URL.Host}}</div>
                         <div class="monitor-latency">Latency: <span name="{{.Name}}latency">unavailable</span></div>
                         <div class="monitor-grid">
                             {{range .Monitor}}

internal/dashboard/templates/traffic.html

@@ -27,7 +27,7 @@
                 {{range $bvalue}}
                 <li>
                     <span class="cir" name="{{.Name}}cir"></span>
-                    <div class="traffic-backend-name">{{.Url}}</div>
+                    <div class="traffic-backend-name">{{.URL.String}}</div>
                     <div class="traffic-counter">Hits: <span name="{{.Name}}hits">{{.Hits}}</span></div>
                 </li>
                 {{end}}

readme.md

@@ -32,7 +32,9 @@ docker compose -f sample/compose.yaml up --build
 
 docker compose -f sample/compose.yaml down
 
-for i in {1..10}; do curl localhost:8080; sleep 1; done;
+for i in {1..10}; do curl -s localhost:8080 | grep h1; sleep 1; done;
+
+seq 1000 | parallel -n0 -j8 "curl -s http://localhost:8080 | grep h1"
 ```
 
 ## Misc

sample/compose.yaml

@@ -32,7 +32,7 @@ services:
       dockerfile: Dockerfile
     environment:
       - FE=localhost,sample
-      - BE=sample,http://be1,sample,http://be2,sample,http://be3
+      - BE=sample,http://host.docker.internal:8081,sample,http://host.docker.internal:8082,sample,http://host.docker.internal:8083
     ports:
       - "8080:8080"
       - "8000:8000"