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/**
* Copyright (C) 2015 MongoDB Inc.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License, version 3,
* as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
* As a special exception, the copyright holders give permission to link the
* code of portions of this program with the OpenSSL library under certain
* conditions as described in each individual source file and distribute
* linked combinations including the program with the OpenSSL library. You
* must comply with the GNU Affero General Public License in all respects for
* all of the code used other than as permitted herein. If you modify file(s)
* with this exception, you may extend this exception to your version of the
* file(s), but you are not obligated to do so. If you do not wish to do so,
* delete this exception statement from your version. If you delete this
* exception statement from all source files in the program, then also delete
* it in the license file.
*/
#include "mongo/platform/basic.h"
#include "mongo/rpc/metadata/sharding_metadata.h"
#include <utility>
#include "mongo/bson/util/bson_extract.h"
#include "mongo/db/jsobj.h"
#include "mongo/util/mongoutils/str.h"
namespace mongo {
namespace rpc {
namespace {
const char kGLEStatsFieldName[] = "$gleStats";
const char kGLEStatsLastOpTimeFieldName[] = "lastOpTime";
const char kGLEStatsElectionIdFieldName[] = "electionId";
} // namespace
StatusWith<ShardingMetadata> ShardingMetadata::readFromMetadata(const BSONObj& metadataObj) {
BSONElement smElem;
auto smExtractStatus = bsonExtractTypedField(metadataObj,
kGLEStatsFieldName,
mongo::Object,
&smElem);
if (!smExtractStatus.isOK()) {
return smExtractStatus;
}
if (smElem.embeddedObject().nFields() != 2) {
return Status(ErrorCodes::InvalidOptions,
str::stream() << "The $gleStats object can only have 2 fields, but got "
<< smElem.embeddedObject().toString());
}
BSONElement lastOpTimeElem;
auto lastOpTimeExtractStatus = bsonExtractTypedField(smElem.embeddedObject(),
kGLEStatsLastOpTimeFieldName,
mongo::bsonTimestamp,
&lastOpTimeElem);
if (!lastOpTimeExtractStatus.isOK()) {
return lastOpTimeExtractStatus;
}
BSONElement lastElectionIdElem;
auto lastElectionIdExtractStatus = bsonExtractTypedField(smElem.embeddedObject(),
kGLEStatsElectionIdFieldName,
mongo::jstOID,
&lastElectionIdElem);
if (!lastElectionIdExtractStatus.isOK()) {
return lastElectionIdExtractStatus;
}
return ShardingMetadata(lastOpTimeElem.timestamp(), lastElectionIdElem.OID());
}
Status ShardingMetadata::writeToMetadata(BSONObjBuilder* metadataBob) const {
BSONObjBuilder subobj(metadataBob->subobjStart(kGLEStatsFieldName));
subobj.append(kGLEStatsLastOpTimeFieldName, getLastOpTime());
subobj.append(kGLEStatsElectionIdFieldName, getLastElectionId());
return Status::OK();
}
Status ShardingMetadata::downconvert(const BSONObj& commandReply,
const BSONObj& replyMetadata,
BSONObjBuilder* legacyCommandReplyBob) {
legacyCommandReplyBob->appendElements(commandReply);
auto swShardingMetadata = readFromMetadata(replyMetadata);
if (swShardingMetadata.isOK()) {
// We can reuse the same logic to write the sharding metadata out to the legacy
// command as the element has the same format whether it is there or on the metadata
// object.
swShardingMetadata.getValue().writeToMetadata(legacyCommandReplyBob);
}
else if (swShardingMetadata.getStatus() == ErrorCodes::NoSuchKey) {
// It is valid to not have a $gleStats field.
}
else {
return swShardingMetadata.getStatus();
}
return Status::OK();
}
Status ShardingMetadata::upconvert(const BSONObj& legacyCommand,
BSONObjBuilder* commandBob,
BSONObjBuilder* metadataBob) {
// We can reuse the same logic to read the sharding metadata out from the legacy command
// as it has the same format whether it is there or on the metadata object.
auto swShardingMetadata = readFromMetadata(legacyCommand);
if (swShardingMetadata.isOK()) {
swShardingMetadata.getValue().writeToMetadata(metadataBob);
// Write out the command excluding the $gleStats subobject.
for (const auto& elem : legacyCommand) {
if (elem.fieldNameStringData() != StringData(kGLEStatsFieldName)) {
commandBob->append(elem);
}
}
} else if (swShardingMetadata.getStatus() == ErrorCodes::NoSuchKey) {
// it is valid to not have a $gleStats field
commandBob->appendElements(legacyCommand);
}
else {
return swShardingMetadata.getStatus();
}
return Status::OK();
}
ShardingMetadata::ShardingMetadata(Timestamp lastOpTime, OID lastElectionId)
: _lastOpTime(std::move(lastOpTime))
, _lastElectionId(std::move(lastElectionId))
{}
const Timestamp& ShardingMetadata::getLastOpTime() const {
return _lastOpTime;
}
const OID& ShardingMetadata::getLastElectionId() const {
return _lastElectionId;
}
} // namespace rpc
} // namespace mongo
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