/**
* Restore or Clone the specified snapshot
*
* @param reqSnapshot
* @param nonceGroup unique value to prevent duplicated RPC
* @param nonce unique value to prevent duplicated RPC
* @throws IOException
*/
public long restoreOrCloneSnapshot(
SnapshotDescription reqSnapshot, final long nonceGroup, final long nonce) throws IOException {
FileSystem fs = master.getMasterFileSystem().getFileSystem();
Path snapshotDir = SnapshotDescriptionUtils.getCompletedSnapshotDir(reqSnapshot, rootDir);
// check if the snapshot exists
if (!fs.exists(snapshotDir)) {
LOG.error("A Snapshot named '" + reqSnapshot.getName() + "' does not exist.");
throw new SnapshotDoesNotExistException(ProtobufUtil.createSnapshotDesc(reqSnapshot));
}
// Get snapshot info from file system. The reqSnapshot is a "fake" snapshotInfo with
// just the snapshot "name" and table name to restore. It does not contains the "real" snapshot
// information.
SnapshotDescription snapshot = SnapshotDescriptionUtils.readSnapshotInfo(fs, snapshotDir);
SnapshotManifest manifest =
SnapshotManifest.open(master.getConfiguration(), fs, snapshotDir, snapshot);
HTableDescriptor snapshotTableDesc = manifest.getTableDescriptor();
TableName tableName = TableName.valueOf(reqSnapshot.getTable());
// stop tracking "abandoned" handlers
cleanupSentinels();
// Verify snapshot validity
SnapshotReferenceUtil.verifySnapshot(master.getConfiguration(), fs, manifest);
// Execute the restore/clone operation
long procId;
if (MetaTableAccessor.tableExists(master.getConnection(), tableName)) {
procId =
restoreSnapshot(reqSnapshot, tableName, snapshot, snapshotTableDesc, nonceGroup, nonce);
} else {
procId =
cloneSnapshot(reqSnapshot, tableName, snapshot, snapshotTableDesc, nonceGroup, nonce);
}
return procId;
}