[Feature] Add EmptyDir to Volumes (#648)

Author: ajanikow

CHANGELOG.md

@@ -1,6 +1,7 @@
 # Change Log
 
 ## [master](https://github.com/arangodb/kube-arangodb/tree/master) (N/A)
+- Allow to mount EmptyDir
 
 ## [1.1.0](https://github.com/arangodb/kube-arangodb/tree/master) (2020-10-14)
 - Change NumberOfCores and MemoryOverride flags to be set to true by default

pkg/apis/deployment/v1/server_group_volume.go

@@ -112,6 +112,9 @@ type ServerGroupSpecVolume struct {
 
 	// ConfigMap which should be mounted into pod
 	ConfigMap *ServerGroupSpecVolumeConfigMap `json:"configMap,omitempty"`
+
+	// EmptyDir
+	EmptyDir *ServerGroupSpecVolumeEmptyDir `json:"emptyDir,omitempty"`
 }
 
 // Validate if ServerGroupSpec volume is valid
@@ -124,6 +127,7 @@ func (s *ServerGroupSpecVolume) Validate() error {
 		shared.PrefixResourceErrors("name", sharedv1.AsKubernetesResourceName(&s.Name).Validate()),
 		shared.PrefixResourceErrors("secret", s.Secret.Validate()),
 		shared.PrefixResourceErrors("configMap", s.ConfigMap.Validate()),
+		shared.PrefixResourceErrors("emptyDir", s.EmptyDir.Validate()),
 		s.validate(),
 	)
 }
@@ -135,22 +139,43 @@ func (s ServerGroupSpecVolume) Volume() core.Volume {
 		VolumeSource: core.VolumeSource{
 			ConfigMap: (*core.ConfigMapVolumeSource)(s.ConfigMap),
 			Secret:    (*core.SecretVolumeSource)(s.Secret),
+			EmptyDir:  (*core.EmptyDirVolumeSource)(s.EmptyDir),
 		},
 	}
 }
 
 func (s *ServerGroupSpecVolume) validate() error {
-	if s.ConfigMap == nil && s.Secret == nil {
-		return errors.Errorf("at least one option need to be defined: secret or configMap")
+	count := s.notNilFields()
+
+	if count == 0 {
+		return errors.Errorf("at least one option need to be defined: secret, configMap or emptyDir")
 	}
 
-	if s.ConfigMap != nil && s.Secret != nil {
-		return errors.Errorf("only one option can be defined: secret or configMap")
+	if count > 1 {
+		return errors.Errorf("only one option can be defined: secret, configMap or emptyDir")
 	}
 
 	return nil
 }
 
+func (s *ServerGroupSpecVolume) notNilFields() int {
+	i := 0
+
+	if s.ConfigMap != nil {
+		i++
+	}
+
+	if s.Secret != nil {
+		i++
+	}
+
+	if s.EmptyDir != nil {
+		i++
+	}
+
+	return i
+}
+
 type ServerGroupSpecVolumeSecret core.SecretVolumeSource
 
 func (s *ServerGroupSpecVolumeSecret) Validate() error {
@@ -174,3 +199,9 @@ func (s *ServerGroupSpecVolumeConfigMap) Validate() error {
 		shared.PrefixResourceError("name", sharedv1.AsKubernetesResourceName(&s.Name).Validate()),
 	)
 }
+
+type ServerGroupSpecVolumeEmptyDir core.EmptyDirVolumeSource
+
+func (s *ServerGroupSpecVolumeEmptyDir) Validate() error {
+	return nil
+}

pkg/apis/deployment/v1/server_group_volume_test.go

@@ -88,7 +88,7 @@ func Test_Volume_Validation(t *testing.T) {
 
 			fail: true,
 			failedFields: map[string]string{
-				"0": "only one option can be defined: secret or configMap",
+				"0": "only one option can be defined: secret, configMap or emptyDir",
 			},
 
 			volumes: []ServerGroupSpecVolume{