Consul hook: resolve port placeholders in tags

hook/consul/hook.go

@@ -21,6 +21,7 @@ const (
 	consulNameLabelKey = "consul"
 	consulTagValue     = "tag"
 	serviceHost        = "127.0.0.1"
+	portPlaceholder    = "{port:%s}"
 )
 
 // instance represents a service in consul
@@ -92,6 +93,7 @@ func (h *Hook) RegisterIntoConsul(taskInfo mesosutils.TaskInfo) error {
 	}
 
 	ports := taskInfo.GetPorts()
+	tagPlaceholders := getPlaceholders(ports)
 	globalTags := append(taskInfo.GetLabelKeysByValue(consulTagValue), h.config.ConsulGlobalTag)
 
 	var instancesToRegister []instance
@@ -133,7 +135,7 @@ func (h *Hook) RegisterIntoConsul(taskInfo mesosutils.TaskInfo) error {
 		serviceRegistration := api.AgentServiceRegistration{
 			ID:                serviceData.consulServiceID,
 			Name:              serviceData.consulServiceName,
-			Tags:              serviceData.tags,
+			Tags:              resolvePlaceholders(serviceData.tags, tagPlaceholders),
 			Port:              int(serviceData.port),
 			Address:           runenv.IP().String(),
 			EnableTagOverride: false,
@@ -172,6 +174,29 @@ func (h *Hook) DeregisterFromConsul(taskInfo mesosutils.TaskInfo) error {
 	return nil
 }
 
+func getPlaceholders(ports []mesos.Port) map[string]string {
+	placeholders := map[string]string{}
+	for _, port := range ports {
+		name := port.GetName()
+		if name != "" {
+			placeholder := fmt.Sprintf(portPlaceholder, name)
+			placeholders[placeholder] = fmt.Sprint(port.GetNumber())
+		}
+	}
+	return placeholders
+}
+
+func resolvePlaceholders(values []string, placeholders map[string]string) []string {
+	resolved := make([]string, 0, len(values))
+	for _, value := range values {
+		for placeholder, replacement := range placeholders {
+			value = strings.Replace(value, placeholder, replacement, -1)
+		}
+		resolved = append(resolved, value)
+	}
+	return resolved
+}
+
 func getServiceLabel(port mesos.Port) (string, error) {
 	label := mesosutils.FindLabel(port.GetLabels().GetLabels(), consulNameLabelKey)
 	if label == nil {

hook/consul/hook_test.go

@@ -349,6 +349,51 @@ func TestIfServiceDeregisteredCorrectly(t *testing.T) {
 	require.NotContains(t, services, consulName)
 }
 
+func TestIfPlaceholdersAreResolved(t *testing.T) {
+
+	adminPortName := "admin"
+	servicePortName := "service"
+	consulName := "serviceName"
+	consulNameAdmin := "serviceName-admin"
+	tagValue := "tag"
+
+	// Create a test Consul server
+	config, server := createTestConsulServer(t)
+	client, _ := api.NewClient(config) // #nosec
+	defer stopConsul(server)
+
+	taskInfo := prepareTaskInfo("taskId", "taskName", "taskName", []string{"service-port:{port:service}"}, []mesos.Port{
+		{Number: 655, Name: &adminPortName, Labels: &mesos.Labels{Labels: []mesos.Label{
+			{Key: "consul", Value: &consulNameAdmin},
+			{Key: "admin", Value: &tagValue},
+		}}},
+		{Number: 766, Labels: &mesos.Labels{Labels: []mesos.Label{
+			{Key: "consul", Value: &consulName},
+			{Key: "admin-port:{port:admin}", Value: &tagValue},
+			{Key: "{port:unknown} is not replaced", Value: &tagValue},
+		}}},
+		{Number: 877, Name: &servicePortName},
+	})
+
+	expectedServiceTags := []string{"marathon", "service-port:877", "admin-port:655", "{port:unknown} is not replaced"}
+	expectedAdminTags := []string{"marathon", "admin", "service-port:877"}
+
+	h := &Hook{config: Config{ConsulGlobalTag: "marathon"}, client: client}
+
+	err := h.RegisterIntoConsul(taskInfo)
+
+	require.NoError(t, err)
+	require.Len(t, h.serviceInstances, 2)
+
+	opts := api.QueryOptions{}
+	services, _, err := client.Catalog().Services(&opts)
+
+	require.Contains(t, services, consulName)
+	requireEqualElements(t, expectedServiceTags, services[consulName])
+	require.Contains(t, services, consulNameAdmin)
+	requireEqualElements(t, expectedAdminTags, services[consulNameAdmin])
+}
+
 func TestIfErrorHandledOnNoConsul(t *testing.T) {
 	consulName := "consulName"
 	taskID := "taskID"