rbd: implement mirroring helpers with go-ceph

mirror.go exposes the helper functions to
perform the mirroring operations.

Signed-off-by: Madhu Rajanna <madhupr007@gmail.com>

internal/rbd/mirror.go

@@ -0,0 +1,155 @@
+/*
+Copyright 2021 The Ceph-CSI Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+package rbd
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"strings"
+
+	"github.com/ceph/ceph-csi/internal/util"
+
+	librbd "github.com/ceph/go-ceph/rbd"
+)
+
+// enableImageMirroring enables mirroring on an image.
+func (rv *rbdVolume) enableImageMirroring(mode librbd.ImageMirrorMode) error {
+	image, err := rv.open()
+	if err != nil {
+		return fmt.Errorf("failed to open image %q with error: %w", rv.String(), err)
+	}
+	defer image.Close()
+
+	err = image.MirrorEnable(mode)
+	if err != nil {
+		return fmt.Errorf("failed to enable mirroring on %q with error: %w", rv.String(), err)
+	}
+	return nil
+}
+
+// disableImageMirroring disables mirroring on an image.
+func (rv *rbdVolume) disableImageMirroring(force bool) error {
+	image, err := rv.open()
+	if err != nil {
+		return fmt.Errorf("failed to open image %q with error: %w", rv.String(), err)
+	}
+	defer image.Close()
+
+	err = image.MirrorDisable(force)
+	if err != nil {
+		return fmt.Errorf("failed to disable mirroring on %q with error: %w", rv.String(), err)
+	}
+	return nil
+}
+
+// getImageMirroringInfo gets mirroring information of an image.
+func (rv *rbdVolume) getImageMirroringInfo() (*librbd.MirrorImageInfo, error) {
+	image, err := rv.open()
+	if err != nil {
+		return nil, fmt.Errorf("failed to open image %q with error: %w", rv.String(), err)
+	}
+	defer image.Close()
+
+	info, err := image.GetMirrorImageInfo()
+	if err != nil {
+		return nil, fmt.Errorf("failed to get mirroring info of %q with error: %w", rv.String(), err)
+	}
+	return info, nil
+}
+
+// promoteImage promotes image to primary.
+func (rv *rbdVolume) promoteImage(force bool) error {
+	image, err := rv.open()
+	if err != nil {
+		return fmt.Errorf("failed to open image %q with error: %w", rv.String(), err)
+	}
+	defer image.Close()
+	err = image.MirrorPromote(force)
+	if err != nil {
+		return fmt.Errorf("failed to promote image %q with error: %w", rv.String(), err)
+	}
+	return nil
+}
+
+// demoteImage demotes image to secondary.
+func (rv *rbdVolume) demoteImage() error {
+	image, err := rv.open()
+	if err != nil {
+		return fmt.Errorf("failed to open image %q with error: %w", rv.String(), err)
+	}
+	defer image.Close()
+	err = image.MirrorDemote()
+	if err != nil {
+		return fmt.Errorf("failed to demote image %q with error: %w", rv.String(), err)
+	}
+	return nil
+}
+
+// resyncImage resync image to correct the split-brain.
+func (rv *rbdVolume) resyncImage() error {
+	image, err := rv.open()
+	if err != nil {
+		return fmt.Errorf("failed to open image %q with error: %w", rv.String(), err)
+	}
+	defer image.Close()
+	err = image.MirrorResync()
+	if err != nil {
+		return fmt.Errorf("failed to resync image %q with error: %w", rv.String(), err)
+	}
+	return nil
+}
+
+type imageMirrorStatus struct {
+	Name        string `json:"name"`  // name of the rbd image
+	State       string `json:"state"` // rbd image state
+	Description string `json:"description"`
+	LastUpdate  string `json:"last_update"`
+}
+
+// FIXME: once https://github.com/ceph/go-ceph/issues/460 is fixed use go-ceph.
+// getImageMirroingStatus get the mirroring status of an image.
+func (rv *rbdVolume) getImageMirroingStatus() (*imageMirrorStatus, error) {
+	// rbd mirror image status --format=json info [image-spec | snap-spec]
+	var imgStatus imageMirrorStatus
+	stdout, stderr, err := util.ExecCommand(
+		context.TODO(),
+		"rbd",
+		"-m", rv.Monitors,
+		"--id", rv.conn.Creds.ID,
+		"--keyfile="+rv.conn.Creds.KeyFile,
+		"-c", util.CephConfigPath,
+		"--format="+"json",
+		"mirror",
+		"image",
+		"status",
+		rv.String())
+	if err != nil {
+		if strings.Contains(stderr, "rbd: error opening image "+rv.RbdImageName+
+			": (2) No such file or directory") {
+			return nil, util.JoinErrors(ErrImageNotFound, err)
+		}
+		return nil, err
+	}
+
+	if stdout != "" {
+		err = json.Unmarshal([]byte(stdout), &imgStatus)
+		if err != nil {
+			return nil, fmt.Errorf("unmarshal failed (%w), raw buffer response: %s", err, stdout)
+		}
+	}
+	return &imgStatus, nil
+}