pkg/{k8s,mesh}: introduce liveness checks

This commit introduces liveness checks to Kilo. This allows the Kilo
daemons to take nodes with inactive or dead Kilo deamons out of the
topology until they are alive again.

pkg/k8s/backend_test.go

@@ -19,7 +19,7 @@ import (
 	"testing"
 
 	"github.com/kylelemons/godebug/pretty"
-	"k8s.io/api/core/v1"
+	v1 "k8s.io/api/core/v1"
 
 	"github.com/squat/kilo/pkg/mesh"
 )
@@ -38,15 +38,15 @@ func TestTranslateNode(t *testing.T) {
 			out:         &mesh.Node{},
 		},
 		{
-			name: "invalid ip",
+			name: "invalid ips",
 			annotations: map[string]string{
 				externalIPAnnotationKey: "10.0.0.1",
-				internalIPAnnotationKey: "10.0.0.1",
+				internalIPAnnotationKey: "foo",
 			},
 			out: &mesh.Node{},
 		},
 		{
-			name: "valid ip",
+			name: "valid ips",
 			annotations: map[string]string{
 				externalIPAnnotationKey: "10.0.0.1/24",
 				internalIPAnnotationKey: "10.0.0.2/32",
@@ -109,6 +109,13 @@ func TestTranslateNode(t *testing.T) {
 				ExternalIP: &net.IPNet{IP: net.ParseIP("10.0.0.2"), Mask: net.CIDRMask(24, 32)},
 			},
 		},
+		{
+			name: "invalid time",
+			annotations: map[string]string{
+				lastSeenAnnotationKey: "foo",
+			},
+			out: &mesh.Node{},
+		},
 		{
 			name: "complete",
 			annotations: map[string]string{
@@ -116,6 +123,7 @@ func TestTranslateNode(t *testing.T) {
 				forceExternalIPAnnotationKey: "10.0.0.2/24",
 				internalIPAnnotationKey:      "10.0.0.2/32",
 				keyAnnotationKey:             "foo",
+				lastSeenAnnotationKey:        "1000000000",
 				leaderAnnotationKey:          "",
 				locationAnnotationKey:        "b",
 			},
@@ -126,6 +134,7 @@ func TestTranslateNode(t *testing.T) {
 				ExternalIP: &net.IPNet{IP: net.ParseIP("10.0.0.2"), Mask: net.CIDRMask(24, 32)},
 				InternalIP: &net.IPNet{IP: net.ParseIP("10.0.0.2"), Mask: net.CIDRMask(32, 32)},
 				Key:        []byte("foo"),
+				LastSeen:   1000000000,
 				Leader:     true,
 				Location:   "b",
 				Subnet:     &net.IPNet{IP: net.ParseIP("10.2.1.0"), Mask: net.CIDRMask(24, 32)},