com.yahoo.vespa.configserver.flags.db.BootstrapFlagSource Maven / Gradle / Ivy
// Copyright Vespa.ai. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
package com.yahoo.vespa.configserver.flags.db;
import com.yahoo.vespa.flags.FetchVector;
import com.yahoo.vespa.flags.FlagId;
import com.yahoo.vespa.flags.FlagSource;
import com.yahoo.vespa.flags.RawFlag;
import com.yahoo.vespa.flags.file.FlagDbFile;
import com.yahoo.vespa.flags.json.FlagData;
import java.nio.file.FileSystem;
import java.util.Map;
import java.util.Optional;
/**
* A flag source that can be used in emergencies, see test for path and format of file.
*
* Use file if the ZooKeeper flag makes it difficult to start the config server, would make irreparable damage,
* or is impossible to change through ZooKeeper due to a bug. This flag source should take precedence over ZooKeeper
* whenever it has specified the value for a flag.
*
* @author hakonhall
*/
public class BootstrapFlagSource implements FlagSource {
private final Map flagData;
public BootstrapFlagSource(FileSystem fileSystem) {
// The flags on disk is read once now and never again.
this.flagData = new FlagDbFile(fileSystem).read();
}
@Override
public Optional fetch(FlagId id, FetchVector vector) {
return Optional.ofNullable(flagData.get(id)).flatMap(data -> data.resolve(vector));
}
}