plugins/hypervisors/kvm/src/main/java/com/cloud/hypervisor/kvm/resource/wrapper/LibvirtRevertSnapshotCommandWrapper.java

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package com.cloud.hypervisor.kvm.resource.wrapper;

import java.io.File;
import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Paths;
import java.nio.file.StandardCopyOption;
import java.util.Set;
import java.util.HashSet;
import java.util.Arrays;

import org.apache.cloudstack.storage.command.RevertSnapshotCommand;
import org.apache.cloudstack.storage.to.PrimaryDataStoreTO;
import org.apache.cloudstack.storage.to.SnapshotObjectTO;
import org.apache.cloudstack.storage.to.VolumeObjectTO;

import com.ceph.rados.IoCTX;
import com.ceph.rados.Rados;
import com.ceph.rados.exceptions.RadosException;
import com.ceph.rbd.Rbd;
import com.ceph.rbd.RbdException;
import com.ceph.rbd.RbdImage;
import com.cloud.agent.api.Answer;
import com.cloud.agent.api.to.DataStoreTO;
import com.cloud.agent.api.to.NfsTO;
import com.cloud.hypervisor.kvm.resource.LibvirtComputingResource;
import com.cloud.hypervisor.kvm.storage.KVMPhysicalDisk;
import com.cloud.hypervisor.kvm.storage.KVMStoragePool;
import com.cloud.hypervisor.kvm.storage.KVMStoragePoolManager;
import com.cloud.resource.CommandWrapper;
import com.cloud.resource.ResourceWrapper;
import com.cloud.storage.DataStoreRole;
import com.cloud.storage.Storage.StoragePoolType;
import com.cloud.utils.Pair;
import com.cloud.utils.exception.CloudRuntimeException;
import com.cloud.utils.script.Script;

@ResourceWrapper(handles = RevertSnapshotCommand.class)
public class LibvirtRevertSnapshotCommandWrapper extends CommandWrapper<RevertSnapshotCommand, Answer, LibvirtComputingResource> {

    private static final String MON_HOST = "mon_host";
    private static final String KEY = "key";
    private static final String CLIENT_MOUNT_TIMEOUT = "client_mount_timeout";
    private static final String RADOS_CONNECTION_TIMEOUT = "30";

    protected Set<StoragePoolType> storagePoolTypesThatSupportRevertSnapshot = new HashSet<>(Arrays.asList(StoragePoolType.RBD, StoragePoolType.Filesystem,
            StoragePoolType.NetworkFilesystem, StoragePoolType.SharedMountPoint));

    @Override
    public Answer execute(final RevertSnapshotCommand command, final LibvirtComputingResource libvirtComputingResource) {
        SnapshotObjectTO snapshotOnPrimaryStorage = command.getDataOnPrimaryStorage();
        SnapshotObjectTO snapshot = command.getData();
        VolumeObjectTO volume = snapshot.getVolume();
        PrimaryDataStoreTO primaryStore = (PrimaryDataStoreTO)volume.getDataStore();
        DataStoreTO snapshotImageStore = snapshot.getDataStore();
        if (!(snapshotImageStore instanceof NfsTO) && !storagePoolTypesThatSupportRevertSnapshot.contains(primaryStore.getPoolType())) {
            return new Answer(command, false,
                    String.format("Revert snapshot does not support storage pool of type [%s]. Revert snapshot is supported by storage pools of type 'NFS' or 'RBD'",
                            primaryStore.getPoolType()));
        }

        String volumePath = volume.getPath();
        String snapshotRelPath = snapshot.getPath();

        try {
            KVMStoragePoolManager storagePoolMgr = libvirtComputingResource.getStoragePoolMgr();

            KVMPhysicalDisk snapshotDisk = storagePoolMgr.getPhysicalDisk(primaryStore.getPoolType(), primaryStore.getUuid(), volumePath);
            KVMStoragePool primaryPool = snapshotDisk.getPool();

            if (primaryPool.getType() == StoragePoolType.RBD) {
                Rados rados = new Rados(primaryPool.getAuthUserName());
                rados.confSet(MON_HOST, primaryPool.getSourceHost() + ":" + primaryPool.getSourcePort());
                rados.confSet(KEY, primaryPool.getAuthSecret());
                rados.confSet(CLIENT_MOUNT_TIMEOUT, RADOS_CONNECTION_TIMEOUT);
                rados.connect();

                String[] rbdPoolAndVolumeAndSnapshot = snapshotRelPath.split("/");
                int snapshotIndex = rbdPoolAndVolumeAndSnapshot.length - 1;
                String rbdSnapshotId = rbdPoolAndVolumeAndSnapshot[snapshotIndex];

                IoCTX io = rados.ioCtxCreate(primaryPool.getSourceDir());
                Rbd rbd = new Rbd(io);

                logger.debug(String.format("Attempting to rollback RBD snapshot [name:%s], [volumeid:%s], [snapshotid:%s]", snapshot.getName(), volumePath, rbdSnapshotId));

                RbdImage image = rbd.open(volumePath);
                image.snapRollBack(rbdSnapshotId);

                rbd.close(image);
                rados.ioCtxDestroy(io);
            } else {
                KVMStoragePool secondaryStoragePool = null;
                if (snapshotImageStore != null && DataStoreRole.Primary != snapshotImageStore.getRole()) {
                    secondaryStoragePool = storagePoolMgr.getStoragePoolByURI(snapshotImageStore.getUrl());
                }

                if (primaryPool.getType() == StoragePoolType.CLVM) {
                    Script cmd = new Script(libvirtComputingResource.manageSnapshotPath(), libvirtComputingResource.getCmdsTimeout(), logger);
                    cmd.add("-v", getFullPathAccordingToStorage(secondaryStoragePool, snapshotRelPath));
                    cmd.add("-n", snapshotDisk.getName());
                    cmd.add("-p", snapshotDisk.getPath());
                    String result = cmd.execute();
                    if (result != null) {
                        logger.debug("Failed to revert snaptshot: " + result);
                        return new Answer(command, false, result);
                    }
                } else {
                    revertVolumeToSnapshot(snapshotOnPrimaryStorage, snapshot, snapshotImageStore, primaryPool, secondaryStoragePool);
                }
            }

            return new Answer(command, true, "RevertSnapshotCommand executes successfully");
        } catch (CloudRuntimeException e) {
            return new Answer(command, false, e.toString());
        } catch (RadosException e) {
            logger.error("Failed to connect to Rados pool while trying to revert snapshot. Exception: ", e);
            return new Answer(command, false, e.toString());
        } catch (RbdException e) {
            logger.error("Failed to connect to revert snapshot due to RBD exception: ", e);
            return new Answer(command, false, e.toString());
        }
    }

    /**
     * Retrieves the full path according to the storage.
     * @return The full path according to the storage.
     */
    protected String getFullPathAccordingToStorage(KVMStoragePool kvmStoragePool, String path) {
        return String.format("%s%s%s", kvmStoragePool.getLocalPath(), File.separator, path);
    }

    /**
     * Reverts the volume to the snapshot.
     */
    protected void revertVolumeToSnapshot(SnapshotObjectTO snapshotOnPrimaryStorage, SnapshotObjectTO snapshotOnSecondaryStorage, DataStoreTO dataStoreTo,
            KVMStoragePool kvmStoragePoolPrimary, KVMStoragePool kvmStoragePoolSecondary) {
        VolumeObjectTO volumeObjectTo = snapshotOnSecondaryStorage.getVolume();
        String volumePath = getFullPathAccordingToStorage(kvmStoragePoolPrimary, volumeObjectTo.getPath());

        Pair<String, SnapshotObjectTO> resultGetSnapshot = getSnapshot(snapshotOnPrimaryStorage, snapshotOnSecondaryStorage, kvmStoragePoolPrimary, kvmStoragePoolSecondary);
        String snapshotPath = resultGetSnapshot.first();
        SnapshotObjectTO snapshotToPrint = resultGetSnapshot.second();

        logger.debug(String.format("Reverting volume [%s] to snapshot [%s].", volumeObjectTo, snapshotToPrint));

        try {
            replaceVolumeWithSnapshot(volumePath, snapshotPath);
            logger.debug(String.format("Successfully reverted volume [%s] to snapshot [%s].", volumeObjectTo, snapshotToPrint));
        } catch (IOException ex) {
            throw new CloudRuntimeException(String.format("Unable to revert volume [%s] to snapshot [%s] due to [%s].", volumeObjectTo, snapshotToPrint, ex.getMessage()), ex);
        }
    }

    /**
     * If the snapshot is backed up on the secondary storage, it will retrieve the snapshot and snapshot path from the secondary storage, otherwise, it will retrieve the snapshot
     * and the snapshot path from the primary storage.
     */
    protected Pair<String, SnapshotObjectTO> getSnapshot(SnapshotObjectTO snapshotOnPrimaryStorage, SnapshotObjectTO snapshotOnSecondaryStorage,
            KVMStoragePool kvmStoragePoolPrimary, KVMStoragePool kvmStoragePoolSecondary) {
        String snapshotPath = null;
        if (snapshotOnPrimaryStorage != null) {
            snapshotPath = snapshotOnPrimaryStorage.getPath();
            if (Files.exists(Paths.get(snapshotPath))) {
                return new Pair<>(snapshotPath, snapshotOnPrimaryStorage);
            }
        }

        if (kvmStoragePoolSecondary == null) {
            throw new CloudRuntimeException(String.format("Snapshot [%s] does not exists on secondary storage, unable to revert volume [%s] to it.",
                    snapshotOnSecondaryStorage, snapshotOnSecondaryStorage.getVolume()));
        }

        if (logger.isTraceEnabled()) {
            logger.trace(String.format("Snapshot does not exists on primary storage [%s], searching snapshot [%s] on secondary storage [%s].",
                    kvmStoragePoolPrimary, snapshotOnSecondaryStorage, kvmStoragePoolSecondary));
        }

        String snapshotPathOnSecondaryStorage = snapshotOnSecondaryStorage.getPath();

        if (snapshotPathOnSecondaryStorage == null) {
            throw new CloudRuntimeException(String.format("Snapshot [%s] was not found on secondary storage neither, unable to revert volume [%s] to it.",
                    snapshotOnSecondaryStorage, snapshotOnSecondaryStorage.getVolume()));
        }

        snapshotPath = getFullPathAccordingToStorage(kvmStoragePoolSecondary, snapshotPathOnSecondaryStorage);
        return new Pair<>(snapshotPath, snapshotOnSecondaryStorage);
    }

    /**
     * Replaces the current volume with the snapshot.
     * @throws IOException If can't replace the current volume with the snapshot.
     */
    protected void replaceVolumeWithSnapshot(String volumePath, String snapshotPath) throws IOException {
        Files.copy(Paths.get(snapshotPath), Paths.get(volumePath), StandardCopyOption.REPLACE_EXISTING);
    }
}