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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.hosted.controller.persistence;
import com.yahoo.component.Version;
import com.yahoo.config.provision.Environment;
import com.yahoo.config.provision.HostName;
import com.yahoo.config.provision.RegionName;
import com.yahoo.slime.ArrayTraverser;
import com.yahoo.slime.Cursor;
import com.yahoo.slime.Inspector;
import com.yahoo.slime.Slime;
import com.yahoo.vespa.hosted.controller.versions.OsVersion;
import com.yahoo.vespa.hosted.controller.versions.OsVersionStatus;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Map;
import java.util.Objects;
import java.util.TreeMap;
/**
* Serializer for {@link OsVersionStatus}.
*
* @author mpolden
*/
public class OsVersionStatusSerializer {
// WARNING: Since there are multiple servers in a ZooKeeper cluster and they upgrade one by one
// (and rewrite all nodes on startup), changes to the serialized format must be made
// such that what is serialized on version N+1 can be read by version N:
// - ADDING FIELDS: Always ok
// - REMOVING FIELDS: Stop reading the field first. Stop writing it on a later version.
// - CHANGING THE FORMAT OF A FIELD: Don't do it bro.
private static final String versionsField = "versions";
private static final String versionField = "version";
private static final String nodesField = "nodes";
private static final String hostnameField = "hostname";
private static final String regionField = "region";
private static final String environmentField = "environment";
private final OsVersionSerializer osVersionSerializer;
public OsVersionStatusSerializer(OsVersionSerializer osVersionSerializer) {
this.osVersionSerializer = Objects.requireNonNull(osVersionSerializer, "osVersionSerializer must be non-null");
}
public Slime toSlime(OsVersionStatus status) {
Slime slime = new Slime();
Cursor root = slime.setObject();
Cursor versions = root.setArray(versionsField);
status.versions().forEach((version, nodes) -> {
Cursor object = versions.addObject();
osVersionSerializer.toSlime(version, object);
nodesToSlime(nodes, object.setArray(nodesField));
});
return slime;
}
public OsVersionStatus fromSlime(Slime slime) {
return new OsVersionStatus(osVersionsFromSlime(slime.get().field(versionsField)));
}
private void nodesToSlime(List<OsVersionStatus.Node> nodes, Cursor array) {
nodes.forEach(node -> nodeToSlime(node, array.addObject()));
}
private void nodeToSlime(OsVersionStatus.Node node, Cursor object) {
object.setString(hostnameField, node.hostname().value());
object.setString(versionField, node.version().toFullString());
object.setString(regionField, node.region().value());
object.setString(environmentField, node.environment().value());
}
private Map<OsVersion, List<OsVersionStatus.Node>> osVersionsFromSlime(Inspector array) {
Map<OsVersion, List<OsVersionStatus.Node>> versions = new TreeMap<>();
array.traverse((ArrayTraverser) (i, object) -> {
OsVersion osVersion = osVersionSerializer.fromSlime(object);
List<OsVersionStatus.Node> nodes = nodesFromSlime(object.field(nodesField));
versions.put(osVersion, nodes);
});
return Collections.unmodifiableMap(versions);
}
private List<OsVersionStatus.Node> nodesFromSlime(Inspector array) {
List<OsVersionStatus.Node> nodes = new ArrayList<>();
array.traverse((ArrayTraverser) (i, object) -> nodes.add(nodeFromSlime(object)));
return Collections.unmodifiableList(nodes);
}
private OsVersionStatus.Node nodeFromSlime(Inspector object) {
return new OsVersionStatus.Node(
HostName.from(object.field(hostnameField).asString()),
Version.fromString(object.field(versionField).asString()),
Environment.from(object.field(environmentField).asString()),
RegionName.from(object.field(regionField).asString())
);
}
}
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