osbuild: add bindings for org.osbuild.containers.storage.conf stage

Add support for the `containers.storage.conf` stage with helper
constructors that should make it easy to use.
Add a small test for it.

internal/osbuild/containers_storage_conf_stage.go

@@ -0,0 +1,58 @@
+package osbuild
+
+import "fmt"
+
+type CSCStorageOptions struct {
+	AdditionalImageStores []string `json:"additionalimagestores,omitempty"`
+}
+
+// CSCStorage is short for ContainersStorageConfigStorage
+type CSCStorage struct {
+	Options *CSCStorageOptions `json:"options,omitempty"`
+}
+
+type ContainersStorageConfig struct {
+	Storage CSCStorage `json:"storage,omitempty"`
+}
+
+type ContainersStorageConfStageOptions struct {
+	Filename string                  `json:"filename,omitempty"`
+	Config   ContainersStorageConfig `json:"config"`
+	Comment  []string                `json:"comment,omitempty"`
+}
+
+func (ContainersStorageConfStageOptions) isStageOptions() {}
+
+func NewContainerStorageOptions(filename string, additionalImageStores ...string) *ContainersStorageConfStageOptions {
+	options := ContainersStorageConfStageOptions{
+		Filename: filename,
+	}
+
+	if len(additionalImageStores) > 0 {
+		options.Config.Storage.Options = &CSCStorageOptions{
+			AdditionalImageStores: additionalImageStores,
+		}
+	}
+
+	return &options
+}
+
+func (o *ContainersStorageConfStageOptions) validate() error {
+	if o.Filename == "" {
+		return fmt.Errorf("`Filename` must be set")
+	}
+
+	return nil
+}
+
+func NewContainersStorageConfStage(options *ContainersStorageConfStageOptions) *Stage {
+
+	if err := options.validate(); err != nil {
+		panic(err)
+	}
+
+	return &Stage{
+		Type:    "org.osbuild.containers.storage.conf",
+		Options: options,
+	}
+}

internal/osbuild/containers_storage_conf_stage_test.go

@@ -0,0 +1,31 @@
+package osbuild
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestContainersStorageConfStage(t *testing.T) {
+	expectedStage := &Stage{
+		Type: "org.osbuild.containers.storage.conf",
+		Options: &ContainersStorageConfStageOptions{
+			Filename: "/usr/share/containers/storage.conf",
+			Config: ContainersStorageConfig{
+				Storage: CSCStorage{
+					Options: &CSCStorageOptions{
+						AdditionalImageStores: []string{
+							"/usr/share/containers/storage/",
+						},
+					},
+				},
+			},
+		},
+	}
+
+	actualStage := NewContainersStorageConfStage(
+		NewContainerStorageOptions("/usr/share/containers/storage.conf",
+			"/usr/share/containers/storage/"),
+	)
+	assert.Equal(t, expectedStage, actualStage)
+}