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// Copyright 2018 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
package com.yahoo.vespa.flags;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.google.inject.Inject;
import com.yahoo.vespa.flags.json.FlagData;
import com.yahoo.vespa.flags.json.Rule;
import java.io.IOException;
import java.io.UncheckedIOException;
import java.nio.charset.StandardCharsets;
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.Collections;
import java.util.Optional;
/**
* @author hakonhall
*/
public class FileFlagSource implements FlagSource {
private static final ObjectMapper mapper = new ObjectMapper();
static final String FLAGS_DIRECTORY = "/etc/vespa/flags";
private final Path flagsDirectory;
@Inject
public FileFlagSource() {
this(FileSystems.getDefault());
}
public FileFlagSource(FileSystem fileSystem) {
this(fileSystem.getPath(FLAGS_DIRECTORY));
}
public FileFlagSource(Path flagsDirectory) {
this.flagsDirectory = flagsDirectory;
}
@Override
public Optional<RawFlag> fetch(FlagId flagId, FetchVector vector) {
return getResolver(flagId).resolve(vector);
}
private FlagData getResolver(FlagId flagId) {
Optional<String> v2String = getString(flagId, ".2");
if (v2String.isPresent()) {
return FlagData.deserialize(v2String.get());
}
Optional<String> v1String = getString(flagId, "");
if (v1String.isPresent()) {
// version 1: File contains value as a JSON
// version 2: File contains FileResolver as a JSON (which may contain many values, one for each rule)
// version 1 files should probably be discontinued
Rule rule = new Rule(Optional.of(JsonNodeRawFlag.fromJson(v1String.get())), Collections.emptyList());
return new FlagData(flagId, new FetchVector(), Collections.singletonList(rule));
}
// Will eventually resolve to empty RawFlag
return new FlagData(flagId);
}
private Optional<String> getString(FlagId id, String suffix) {
return getBytes(id, suffix).map(bytes -> new String(bytes, StandardCharsets.UTF_8));
}
private Optional<byte[]> getBytes(FlagId id, String suffix) {
try {
return Optional.of(Files.readAllBytes(getPath(id, suffix)));
} catch (NoSuchFileException e) {
return Optional.empty();
} catch (IOException e) {
throw new UncheckedIOException(e);
}
}
private Path getPath(FlagId id, String suffix) {
return flagsDirectory.resolve(id.toString() + suffix);
}
@Override
public String toString() {
return "FileFlagSource{" + flagsDirectory + '}';
}
}
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