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// Copyright Yahoo. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
package com.yahoo.vespa.flags.file;
import java.util.logging.Level;
import com.yahoo.vespa.defaults.Defaults;
import com.yahoo.vespa.flags.FlagId;
import com.yahoo.vespa.flags.json.FlagData;
import java.io.IOException;
import java.io.UncheckedIOException;
import java.nio.file.FileSystem;
import java.nio.file.FileSystems;
import java.nio.file.Files;
import java.nio.file.NoSuchFileException;
import java.nio.file.Path;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Objects;
import java.util.Optional;
import java.util.Set;
import java.util.function.Function;
import java.util.logging.Logger;
import java.util.stream.Collectors;
import static com.yahoo.yolean.Exceptions.uncheck;
/**
* Java API for a flag database stored in a single file
*
* @author hakonhall
*/
public class FlagDbFile {
private static final Logger logger = Logger.getLogger(FlagDbFile.class.getName());
private final Path path;
public FlagDbFile() {
this(FileSystems.getDefault());
}
public FlagDbFile(FileSystem fileSystem) {
this(fileSystem.getPath(Defaults.getDefaults().underVespaHome("var/vespa/flag.db")));
}
public FlagDbFile(Path path) {
this.path = path;
}
public Path getPath() {
return path;
}
public Map<FlagId, FlagData> read() {
Optional<byte[]> bytes = readFile();
if (!bytes.isPresent()) return Collections.emptyMap();
return FlagData.deserializeList(bytes.get()).stream().collect(Collectors.toMap(FlagData::id, Function.identity()));
}
public boolean sync(Map<FlagId, FlagData> flagData) {
boolean modified = false;
Map<FlagId, FlagData> currentFlagData = read();
Set<FlagId> flagIdsToBeRemoved = new HashSet<>(currentFlagData.keySet());
List<FlagData> flagDataList = new ArrayList<>(flagData.values());
for (FlagData data : flagDataList) {
flagIdsToBeRemoved.remove(data.id());
FlagData existingFlagData = currentFlagData.get(data.id());
if (existingFlagData == null) {
logger.log(Level.INFO, "New flag " + data.id() + ": " + data.serializeToJson());
modified = true;
// Could also consider testing with FlagData::equals, but that would be too fragile?
} else if (!Objects.equals(data.serializeToJson(), existingFlagData.serializeToJson())){
logger.log(Level.INFO, "Updating flag " + data.id() + " from " +
existingFlagData.serializeToJson() + " to " + data.serializeToJson());
modified = true;
}
}
if (!flagIdsToBeRemoved.isEmpty()) {
String flagIdsString = flagIdsToBeRemoved.stream().map(FlagId::toString).collect(Collectors.joining(", "));
logger.log(Level.INFO, "Removing flags " + flagIdsString);
modified = true;
}
if (!modified) return false;
writeFile(FlagData.serializeListToUtf8Json(flagDataList));
return modified;
}
private Optional<byte[]> readFile() {
try {
return Optional.of(Files.readAllBytes(path));
} catch (NoSuchFileException e) {
return Optional.empty();
} catch (IOException e) {
throw new UncheckedIOException(e);
}
}
private void writeFile(byte[] bytes) {
uncheck(() -> Files.createDirectories(path.getParent()));
uncheck(() -> Files.write(path, bytes));
}
}
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