[bugfix] Add IP to endpoint key. (cloudprober#535)

HTTP probes use endpoint key as identifier to decide when to recreate
probes. During VM recreations, it is possible for VM name to stay the
same but VM IP changes. By adding IP to key, we ensure that in such
cases, HTTP probes are recreated.

targets/endpoint/endpoint.go

@@ -47,7 +47,11 @@ func (ep *Endpoint) Key() string {
 	}
 	sort.Strings(labelSlice)
 
-	return strings.Join(append([]string{ep.Name, strconv.Itoa(ep.Port)}, labelSlice...), "_")
+	ip := ""
+	if ep.IP != nil {
+		ip = ep.IP.String()
+	}
+	return strings.Join(append([]string{ep.Name, ip, strconv.Itoa(ep.Port)}, labelSlice...), "_")
 }
 
 // Lister should implement the ListEndpoints method.

targets/endpoint/endpoint_test.go

@@ -16,6 +16,7 @@ package endpoint
 
 import (
 	"fmt"
+	"net"
 	"testing"
 
 	"github.com/stretchr/testify/assert"
@@ -45,24 +46,27 @@ func TestKey(t *testing.T) {
 		name   string
 		port   int
 		labels map[string]string
+		ip     net.IP
 		key    string
 	}{
 		{
 			name: "t1",
 			port: 80,
-			key:  "t1_80",
+			ip:   net.ParseIP("10.0.0.1"),
+			key:  "t1_10.0.0.1_80",
 		},
 		{
 			name:   "t1",
 			port:   80,
+			ip:     net.ParseIP("1234:5678::72"),
 			labels: map[string]string{"app": "cloudprober", "dc": "xx"},
-			key:    "t1_80_app:cloudprober_dc:xx",
+			key:    "t1_1234:5678::72_80_app:cloudprober_dc:xx",
 		},
 		{
 			name:   "t1",
 			port:   80,
 			labels: map[string]string{"dc": "xx", "app": "cloudprober"},
-			key:    "t1_80_app:cloudprober_dc:xx",
+			key:    "t1__80_app:cloudprober_dc:xx",
 		},
 	} {
 		ep := Endpoint{