Test Headless Services

pkg/testutils/kubernetes.go

@@ -0,0 +1,27 @@
+package testutils
+
+import (
+	"errors"
+
+	"k8s.io/kubernetes/pkg/api"
+	"k8s.io/kubernetes/pkg/runtime"
+)
+
+// CheckForHeadless is helper function for tests.
+// It checks if all Services in objects are Headless Services and if there is at least one such Services.
+func CheckForHeadless(objects []runtime.Object) error {
+	serviceCreated := false
+	for _, obj := range objects {
+		if svc, ok := obj.(*api.Service); ok {
+			serviceCreated = true
+			// Check if it is a headless services
+			if svc.Spec.ClusterIP != "None" {
+				return errors.New("this is not a Headless services")
+			}
+		}
+	}
+	if !serviceCreated {
+		return errors.New("no Service created")
+	}
+	return nil
+}

pkg/transformer/kubernetes/k8sutils.go

@@ -282,7 +282,11 @@ func (k *Kubernetes) CreateService(name string, service kobject.ServiceConfig, o
 	return svc
 }
 
-// CreateHeadlessService creates a k8s headless service
+// CreateHeadlessService creates a k8s headless service.
+// Thi is used for docker-compose services without ports. For such services we can't create regular Kubernetes Service.
+// and without Service Pods can't find each other using DNS names.
+// Instead of regular Kubernetes Service we create Headless Service. DNS of such service points directly to Pod IP address.
+// You can find more about Headless Services in Kubernetes documentation https://kubernetes.io/docs/user-guide/services/#headless-services
 func (k *Kubernetes) CreateHeadlessService(name string, service kobject.ServiceConfig, objects []runtime.Object) *api.Service {
 	svc := k.InitSvc(name, service)
 

pkg/transformer/kubernetes/k8sutils_test.go

@@ -24,6 +24,8 @@ import (
 	"path/filepath"
 
 	"github.com/kubernetes-incubator/kompose/pkg/kobject"
+	"github.com/kubernetes-incubator/kompose/pkg/testutils"
+
 	"k8s.io/kubernetes/pkg/api"
 	"k8s.io/kubernetes/pkg/apis/extensions"
 )
@@ -161,3 +163,22 @@ func TestIsDir(t *testing.T) {
 		t.Errorf("Error removing the temporary directory during cleanup: %v", err)
 	}
 }
+
+// TestServiceWithoutPort this tests if Headless Service is created for services without Port.
+func TestServiceWithoutPort(t *testing.T) {
+	service := kobject.ServiceConfig{
+		ContainerName: "name",
+		Image:         "image",
+	}
+
+	komposeObject := kobject.KomposeObject{
+		ServiceConfigs: map[string]kobject.ServiceConfig{"app": service},
+	}
+	k := Kubernetes{}
+
+	objects := k.Transform(komposeObject, kobject.ConvertOptions{CreateD: true, Replicas: 1})
+	if err := testutils.CheckForHeadless(objects); err != nil {
+		t.Error(err)
+	}
+
+}

pkg/transformer/openshift/openshift_test.go

@@ -28,6 +28,7 @@ import (
 
 	"github.com/kubernetes-incubator/kompose/pkg/kobject"
 	"github.com/kubernetes-incubator/kompose/pkg/testutils"
+	"github.com/kubernetes-incubator/kompose/pkg/transformer/kubernetes"
 )
 
 func newServiceConfig() kobject.ServiceConfig {
@@ -309,3 +310,22 @@ func TestInitBuildConfig(t *testing.T) {
 		}
 	}
 }
+
+// TestServiceWithoutPort this tests if Headless Service is created for services without Port.
+func TestServiceWithoutPort(t *testing.T) {
+	service := kobject.ServiceConfig{
+		ContainerName: "name",
+		Image:         "image",
+	}
+
+	komposeObject := kobject.KomposeObject{
+		ServiceConfigs: map[string]kobject.ServiceConfig{"app": service},
+	}
+	o := OpenShift{Kubernetes: kubernetes.Kubernetes{}}
+
+	objects := o.Transform(komposeObject, kobject.ConvertOptions{CreateD: true, Replicas: 1})
+	if err := testutils.CheckForHeadless(objects); err != nil {
+		t.Error(err)
+	}
+
+}