rbd admin: add type ImageSpec to work with rbd task api

ImageSpec type has been added to work with rbd task api.
It consists of optional pool & namespace and image name/id.
[pool/][namespace/]image[Name/id].
Added unit tests.

Signed-off-by: Rakshith R <rar@redhat.com>

rbd/admin/imagespec.go

@@ -0,0 +1,43 @@
+// +build !nautilus,ceph_preview
+
+package admin
+
+import (
+	"fmt"
+)
+
+// ImageSpec values are used to identify an RBD image wherever Ceph APIs
+// require an image_spec/image_id_spec using image name/id and optional
+// pool and namespace.
+// PREVIEW
+type ImageSpec struct {
+	spec string
+}
+
+// NewImageSpec is used to construct an ImageSpec given an image name/id
+// and optional namespace and pool names.
+// NewImageSpec constructs an ImageSpec to identify an RBD image and thus
+// requires image name/id, whereas NewLevelSpec constructs LevelSpec to
+// identify entire pool, pool namespace or single RBD image, all of which
+// requires pool name.
+// PREVIEW
+func NewImageSpec(pool, namespace, image string) ImageSpec {
+	var s string
+	if pool != "" && namespace != "" {
+		s = fmt.Sprintf("%s/%s/%s", pool, namespace, image)
+	} else if pool != "" {
+		s = fmt.Sprintf("%s/%s", pool, image)
+	} else {
+		s = image
+	}
+	return ImageSpec{s}
+}
+
+// NewRawImageSpec returns a ImageSpec directly based on the spec string
+// argument without constructing it from component values. This should only be
+// used if NewImageSpec can not create the imagespec value you want to pass to
+// ceph.
+// PREVIEW
+func NewRawImageSpec(spec string) ImageSpec {
+	return ImageSpec{spec}
+}

rbd/admin/imagespec_test.go

@@ -0,0 +1,96 @@
+// +build !nautilus,ceph_preview
+
+package admin
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestNewImageSpec(t *testing.T) {
+	type args struct {
+		pool      string
+		namespace string
+		image     string
+	}
+	tests := []struct {
+		name string
+		args args
+		want ImageSpec
+	}{
+		{
+			name: "onlyImageName",
+			args: args{
+				pool:      "",
+				namespace: "",
+				image:     "img",
+			},
+			want: ImageSpec{
+				spec: "img",
+			},
+		},
+		{
+			name: "Image&PoolName",
+			args: args{
+				pool:      "pool",
+				namespace: "",
+				image:     "img",
+			},
+			want: ImageSpec{
+				spec: "pool/img",
+			},
+		},
+		{
+			name: "all args",
+			args: args{
+				pool:      "pool",
+				namespace: "ns",
+				image:     "img",
+			},
+			want: ImageSpec{
+				spec: "pool/ns/img",
+			},
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			assert.Equal(t, tt.want, NewImageSpec(tt.args.pool, tt.args.namespace, tt.args.image))
+		})
+	}
+}
+
+func TestNewRawImageSpec(t *testing.T) {
+	type args struct {
+		spec string
+	}
+	tests := []struct {
+		name string
+		args args
+		want ImageSpec
+	}{
+		{
+			name: "valid",
+			args: args{
+				spec: "pool/img",
+			},
+			want: ImageSpec{
+				spec: "pool/img",
+			},
+		},
+		{
+			name: "invalid but still accepts",
+			args: args{
+				spec: "invalid format ...",
+			},
+			want: ImageSpec{
+				spec: "invalid format ...",
+			},
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			assert.Equal(t, tt.want, NewRawImageSpec(tt.args.spec))
+		})
+	}
+}