Add support for configmap volumes to play kube

If the k8s yaml has volumes from a configmap, play kube
will now create a volume based on the data from the
configmap and volume source and set it to the right path
in the container accordingly.
Add tests for this and update some test for ENV from configmap.

Signed-off-by: Urvashi Mohnani <umohnani@redhat.com>

2 files changed, 69 insertions, 7 deletions

diff --git a/pkg/specgen/generate/kube/kube.go b/pkg/specgen/generate/kube/kube.go
index c502a6e62..6d9f598c9 100644
--- a/pkg/specgen/generate/kube/kube.go
+++ b/pkg/specgen/generate/kube/kube.go
@@ -310,6 +310,11 @@ func ToSpecGen(ctx context.Context, opts *CtrSpecGenOptions) (*specgen.SpecGener
 		if !exists {
 			return nil, errors.Errorf("Volume mount %s specified for container but not configured in volumes", volume.Name)
 		}
+		// Skip if the volume is optional. This means that a configmap for a configmap volume was not found but it was
+		// optional so we can move on without throwing an error
+		if exists && volumeSource.Optional {
+			continue
+		}
 
 		dest, options, err := parseMountPath(volume.MountPath, volume.ReadOnly)
 		if err != nil {
@@ -341,6 +346,13 @@ func ToSpecGen(ctx context.Context, opts *CtrSpecGenOptions) (*specgen.SpecGener
 				Options: options,
 			}
 			s.Volumes = append(s.Volumes, &namedVolume)
+		case KubeVolumeTypeConfigMap:
+			cmVolume := specgen.NamedVolume{
+				Dest:    volume.MountPath,
+				Name:    volumeSource.Source,
+				Options: options,
+			}
+			s.Volumes = append(s.Volumes, &cmVolume)
 		default:
 			return nil, errors.Errorf("Unsupported volume source type")
 		}
diff --git a/pkg/specgen/generate/kube/volume.go b/pkg/specgen/generate/kube/volume.go
index a8042b532..76ec0a390 100644
--- a/pkg/specgen/generate/kube/volume.go
+++ b/pkg/specgen/generate/kube/volume.go
@@ -23,6 +23,7 @@ type KubeVolumeType int
 const (
 	KubeVolumeTypeBindMount KubeVolumeType = iota
 	KubeVolumeTypeNamed     KubeVolumeType = iota
+	KubeVolumeTypeConfigMap KubeVolumeType = iota
 )
 
 // nolint:golint
@@ -31,6 +32,14 @@ type KubeVolume struct {
 	Type KubeVolumeType
 	// Path for bind mount or volume name for named volume
 	Source string
+	// Items to add to a named volume created where the key is the file name and the value is the data
+	// This is only used when there are volumes in the yaml that refer to a configmap
+	// Example: if configmap has data "SPECIAL_LEVEL: very" then the file name is "SPECIAL_LEVEL" and the
+	// data in that file is "very".
+	Items map[string]string
+	// If the volume is optional, we can move on if it is not found
+	// Only used when there are volumes in a yaml that refer to a configmap
+	Optional bool
 }
 
 // Create a KubeVolume from an HostPathVolumeSource
@@ -98,23 +107,64 @@ func VolumeFromPersistentVolumeClaim(claim *v1.PersistentVolumeClaimVolumeSource
 	}, nil
 }
 
+func VolumeFromConfigMap(configMapVolumeSource *v1.ConfigMapVolumeSource, configMaps []v1.ConfigMap) (*KubeVolume, error) {
+	var configMap *v1.ConfigMap
+	kv := &KubeVolume{Type: KubeVolumeTypeConfigMap, Items: map[string]string{}}
+	for _, cm := range configMaps {
+		if cm.Name == configMapVolumeSource.Name {
+			matchedCM := cm
+			// Set the source to the config map name
+			kv.Source = cm.Name
+			configMap = &matchedCM
+			break
+		}
+	}
+
+	if configMap == nil {
+		// If the volumeSource was optional, move on even if a matching configmap wasn't found
+		if *configMapVolumeSource.Optional {
+			kv.Source = configMapVolumeSource.Name
+			kv.Optional = *configMapVolumeSource.Optional
+			return kv, nil
+		}
+		return nil, errors.Errorf("no such ConfigMap %q", configMapVolumeSource.Name)
+	}
+
+	// If there are Items specified in the volumeSource, that overwrites the Data from the configmap
+	if len(configMapVolumeSource.Items) > 0 {
+		for _, item := range configMapVolumeSource.Items {
+			if val, ok := configMap.Data[item.Key]; ok {
+				kv.Items[item.Path] = val
+			}
+		}
+	} else {
+		for k, v := range configMap.Data {
+			kv.Items[k] = v
+		}
+	}
+	return kv, nil
+}
+
 // Create a KubeVolume from one of the supported VolumeSource
-func VolumeFromSource(volumeSource v1.VolumeSource) (*KubeVolume, error) {
-	if volumeSource.HostPath != nil {
+func VolumeFromSource(volumeSource v1.VolumeSource, configMaps []v1.ConfigMap) (*KubeVolume, error) {
+	switch {
+	case volumeSource.HostPath != nil:
 		return VolumeFromHostPath(volumeSource.HostPath)
-	} else if volumeSource.PersistentVolumeClaim != nil {
+	case volumeSource.PersistentVolumeClaim != nil:
 		return VolumeFromPersistentVolumeClaim(volumeSource.PersistentVolumeClaim)
-	} else {
-		return nil, errors.Errorf("HostPath and PersistentVolumeClaim are currently the only supported VolumeSource")
+	case volumeSource.ConfigMap != nil:
+		return VolumeFromConfigMap(volumeSource.ConfigMap, configMaps)
+	default:
+		return nil, errors.Errorf("HostPath, ConfigMap, and PersistentVolumeClaim are currently the only supported VolumeSource")
 	}
 }
 
 // Create a map of volume name to KubeVolume
-func InitializeVolumes(specVolumes []v1.Volume) (map[string]*KubeVolume, error) {
+func InitializeVolumes(specVolumes []v1.Volume, configMaps []v1.ConfigMap) (map[string]*KubeVolume, error) {
 	volumes := make(map[string]*KubeVolume)
 
 	for _, specVolume := range specVolumes {
-		volume, err := VolumeFromSource(specVolume.VolumeSource)
+		volume, err := VolumeFromSource(specVolume.VolumeSource, configMaps)
 		if err != nil {
 			return nil, errors.Wrapf(err, "failed to create volume %q", specVolume.Name)
 		}