Add functions for default api objects

This allows to avoid nil pointers when working with unmarshaled
objects, that may be missing some fields.

Next step would be to revisit why pointers are used in such obj
as Clusterctl and ImageConfiguration

Change-Id: I99a711529a53943ef1b0cb1ebb4d240f2482fac8

pkg/api/v1alpha1/cluster_map_types.go

@@ -36,3 +36,10 @@ type Cluster struct {
 	// expecting it to be in document bundle. Parent kubeconfig will be used to get kubeconfig
 	DynamicKubeConfig bool `json:"dynamicKubeConf,omitempty"`
 }
+
+// DefaultClusterMap can be used to safely unmarshal ClusterMap object without nil pointers
+func DefaultClusterMap() *ClusterMap {
+	return &ClusterMap{
+		Map: make(map[string]*Cluster),
+	}
+}

pkg/api/v1alpha1/clusterctl_types.go

@@ -105,3 +105,12 @@ type MoveOptions struct {
 	// The namespace where the workload cluster is hosted. If unspecified, the target context's namespace is used.
 	Namespace string `json:"namespace,omitempty"`
 }
+
+// DefaultClusterctl can be used to safely unmarshal Clusterctl object without nil pointers
+func DefaultClusterctl() *Clusterctl {
+	return &Clusterctl{
+		InitOptions: &InitOptions{},
+		MoveOptions: &MoveOptions{},
+		Providers:   make([]*Provider, 0),
+	}
+}

pkg/api/v1alpha1/imageconfiguration_types.go

@@ -49,3 +49,11 @@ type ImageConfiguration struct {
 	Container *Container `json:"container,omitempty"`
 	Builder   *Builder   `json:"builder,omitempty"`
 }
+
+// DefaultImageConfiguration can be used to safely unmarshal ImageConfiguration object without nil pointers
+func DefaultImageConfiguration() *ImageConfiguration {
+	return &ImageConfiguration{
+		Container: &Container{},
+		Builder:   &Builder{},
+	}
+}

pkg/api/v1alpha1/phase_types.go

@@ -34,3 +34,12 @@ type PhaseConfig struct {
 	ExecutorRef        *corev1.ObjectReference `json:"executorRef"`
 	DocumentEntryPoint string                  `json:"documentEntryPoint"`
 }
+
+// DefaultPhase can be used to safely unmarshal phase object without nil pointers
+func DefaultPhase() *Phase {
+	return &Phase{
+		Config: PhaseConfig{
+			ExecutorRef: &corev1.ObjectReference{},
+		},
+	}
+}

pkg/bootstrap/isogen/executor.go

@@ -42,7 +42,7 @@ type Executor struct {
 
 // RegisterExecutor adds executor to phase executor registry
 func RegisterExecutor(registry map[schema.GroupVersionKind]ifc.ExecutorFactory) error {
-	obj := &v1alpha1.ImageConfiguration{}
+	obj := v1alpha1.DefaultImageConfiguration()
 	gvks, _, err := v1alpha1.Scheme.ObjectKinds(obj)
 	if err != nil {
 		return err

pkg/clusterctl/client/executor.go

@@ -55,7 +55,7 @@ func RegisterExecutor(registry map[schema.GroupVersionKind]ifc.ExecutorFactory)
 
 // NewExecutor creates instance of 'clusterctl init' phase executor
 func NewExecutor(cfg ifc.ExecutorConfig) (ifc.Executor, error) {
-	options := &airshipv1.Clusterctl{}
+	options := airshipv1.DefaultClusterctl()
 	if err := cfg.ExecutorDocument.ToAPIObject(options, airshipv1.Scheme); err != nil {
 		return nil, err
 	}

pkg/phase/helper.go

@@ -76,6 +76,8 @@ func (helper *Helper) Phase(phaseID ifc.ID) (*v1alpha1.Phase, error) {
 	if err != nil {
 		return nil, err
 	}
+	// Overwrite phase used for selector, with a phase with default values
+	phase = v1alpha1.DefaultPhase()
 	if err = doc.ToAPIObject(phase, v1alpha1.Scheme); err != nil {
 		return nil, err
 	}
@@ -126,7 +128,7 @@ func (helper *Helper) ListPhases() ([]*v1alpha1.Phase, error) {
 
 	phases := []*v1alpha1.Phase{}
 	for _, doc := range docs {
-		p := &v1alpha1.Phase{}
+		p := v1alpha1.DefaultPhase()
 		if err = doc.ToAPIObject(p, v1alpha1.Scheme); err != nil {
 			return nil, err
 		}
@@ -142,7 +144,7 @@ func (helper *Helper) ClusterMapAPIobj() (*v1alpha1.ClusterMap, error) {
 		return nil, err
 	}
 
-	cMap := &v1alpha1.ClusterMap{}
+	cMap := v1alpha1.DefaultClusterMap()
 	selector, err := document.NewSelector().ByObject(cMap, v1alpha1.Scheme)
 	if err != nil {
 		return nil, err