| /* |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you 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 org.apache.drill.exec.store; |
| |
| import java.io.IOException; |
| |
| import org.apache.drill.exec.planner.logical.StoragePlugins; |
| |
| /** |
| * Generalized interface for bootstraping or upgrading the plugin persistent |
| * store. Provides the list of bootstrap plugins, along with those to be |
| * upgraded. Provides confirmation that the upgrade was performed to avoid |
| * doing it again. |
| * <p> |
| * <b>Caveats:</b>: The upgrade mechanism is rather ad-hoc; it actually needs |
| * a version number to be solid, but the persistent store does not currently |
| * provide a version number. See DRILL-7613. |
| */ |
| public interface PluginBootstrapLoader { |
| |
| /** |
| * Drill has detected that this is a new installation. Provide |
| * the list of storage plugins (that is, names and configs) |
| * to use to populate the storage plugin store. |
| */ |
| StoragePlugins bootstrapPlugins() throws IOException; |
| |
| /** |
| * Drill has detected that on restart, the persistent storage |
| * plugin exists. Return any changes that should be applied. |
| * <p> |
| * Note: this functionality is crude, there is no version, all |
| * Drillbits in a cluster will race to do the upgrade. |
| * Caveat emptor. See DRILL-7613. |
| */ |
| StoragePlugins updatedPlugins(); |
| |
| /** |
| * Drill successfully applied the plugin upgrades from |
| * {@link #updatedPlugins()}. Use this event to mark this |
| * version as having been upgraded. (Again, this is crude and |
| * may not actually work. See DRILL-7613.) |
| */ |
| void onUpgrade(); |
| } |