org.apache.drill.exec.store.PluginBootstrapLoader Maven / Gradle / Ivy
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* Licensed to the Apache Software Foundation (ASF) under one
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* distributed with this work for additional information
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* 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,
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*/
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.
*
* Caveats:: 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.
*
* 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();
}