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/**
* Copyright (C) 2018-present MongoDB, Inc.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the Server Side Public License, version 1,
* as published by MongoDB, Inc.
*
* 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
* Server Side Public License for more details.
*
* You should have received a copy of the Server Side Public License
* along with this program. If not, see
* <http://www.mongodb.com/licensing/server-side-public-license>.
*
* 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 Server Side 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.
*/
#define MONGO_LOG_DEFAULT_COMPONENT ::mongo::logger::LogComponent::kReplication
#include "mongo/platform/basic.h"
#include "mongo/db/repl/read_concern_args.h"
#include "mongo/bson/util/bson_extract.h"
#include "mongo/db/jsobj.h"
#include "mongo/db/logical_time.h"
#include "mongo/db/operation_context.h"
#include "mongo/db/repl/bson_extract_optime.h"
#include "mongo/util/str.h"
using std::string;
namespace mongo {
namespace repl {
const OperationContext::Decoration<ReadConcernArgs> handle =
OperationContext::declareDecoration<ReadConcernArgs>();
ReadConcernArgs& ReadConcernArgs::get(OperationContext* opCtx) {
return handle(opCtx);
}
const ReadConcernArgs& ReadConcernArgs::get(const OperationContext* opCtx) {
return handle(opCtx);
}
ReadConcernArgs::ReadConcernArgs() : _specified(false) {}
ReadConcernArgs::ReadConcernArgs(boost::optional<ReadConcernLevel> level)
: _level(std::move(level)), _specified(_level) {}
ReadConcernArgs::ReadConcernArgs(boost::optional<OpTime> opTime,
boost::optional<ReadConcernLevel> level)
: _opTime(std::move(opTime)), _level(std::move(level)), _specified(_opTime || _level) {}
ReadConcernArgs::ReadConcernArgs(boost::optional<LogicalTime> clusterTime,
boost::optional<ReadConcernLevel> level)
: _afterClusterTime(std::move(clusterTime)),
_level(std::move(level)),
_specified(_afterClusterTime || _level) {}
std::string ReadConcernArgs::toString() const {
return toBSON().toString();
}
BSONObj ReadConcernArgs::toBSON() const {
BSONObjBuilder bob;
appendInfo(&bob);
return bob.obj();
}
bool ReadConcernArgs::isEmpty() const {
return !_afterClusterTime && !_opTime && !_atClusterTime && !_level;
}
bool ReadConcernArgs::isSpecified() const {
return _specified;
}
ReadConcernLevel ReadConcernArgs::getLevel() const {
return _level.value_or(ReadConcernLevel::kLocalReadConcern);
}
bool ReadConcernArgs::hasLevel() const {
return _level.is_initialized();
}
boost::optional<OpTime> ReadConcernArgs::getArgsOpTime() const {
return _opTime;
}
boost::optional<LogicalTime> ReadConcernArgs::getArgsAfterClusterTime() const {
return _afterClusterTime;
}
boost::optional<LogicalTime> ReadConcernArgs::getArgsAtClusterTime() const {
return _atClusterTime;
}
Status ReadConcernArgs::initialize(const BSONElement& readConcernElem) {
invariant(isEmpty()); // only legal to call on uninitialized object.
_specified = false;
if (readConcernElem.eoo()) {
return Status::OK();
}
dassert(readConcernElem.fieldNameStringData() == kReadConcernFieldName);
if (readConcernElem.type() != Object) {
return Status(ErrorCodes::FailedToParse,
str::stream() << kReadConcernFieldName << " field should be an object");
}
return parse(readConcernElem.Obj());
}
Status ReadConcernArgs::parse(const BSONObj& readConcernObj) {
invariant(isEmpty()); // only legal to call on uninitialized object.
for (auto&& field : readConcernObj) {
auto fieldName = field.fieldNameStringData();
if (fieldName == kAfterOpTimeFieldName) {
OpTime opTime;
// TODO pass field in rather than scanning again.
auto opTimeStatus =
bsonExtractOpTimeField(readConcernObj, kAfterOpTimeFieldName, &opTime);
if (!opTimeStatus.isOK()) {
return opTimeStatus;
}
_opTime = opTime;
} else if (fieldName == kAfterClusterTimeFieldName) {
Timestamp afterClusterTime;
auto afterClusterTimeStatus = bsonExtractTimestampField(
readConcernObj, kAfterClusterTimeFieldName, &afterClusterTime);
if (!afterClusterTimeStatus.isOK()) {
return afterClusterTimeStatus;
}
_afterClusterTime = LogicalTime(afterClusterTime);
} else if (fieldName == kAtClusterTimeFieldName) {
Timestamp atClusterTime;
auto atClusterTimeStatus =
bsonExtractTimestampField(readConcernObj, kAtClusterTimeFieldName, &atClusterTime);
if (!atClusterTimeStatus.isOK()) {
return atClusterTimeStatus;
}
_atClusterTime = LogicalTime(atClusterTime);
} else if (fieldName == kLevelFieldName) {
std::string levelString;
// TODO pass field in rather than scanning again.
auto readCommittedStatus =
bsonExtractStringField(readConcernObj, kLevelFieldName, &levelString);
if (!readCommittedStatus.isOK()) {
return readCommittedStatus;
}
_level = readConcernLevels::fromString(levelString);
if (!_level) {
return Status(ErrorCodes::FailedToParse,
str::stream() << kReadConcernFieldName << '.' << kLevelFieldName
<< " must be either '" << readConcernLevels::kLocalName
<< "', '" << readConcernLevels::kMajorityName << "', '"
<< readConcernLevels::kLinearizableName << "', '"
<< readConcernLevels::kAvailableName << "', or '"
<< readConcernLevels::kSnapshotName << "'");
}
} else {
return Status(ErrorCodes::InvalidOptions,
str::stream() << "Unrecognized option in " << kReadConcernFieldName
<< ": " << fieldName);
}
}
if (_afterClusterTime && _opTime) {
return Status(ErrorCodes::InvalidOptions,
str::stream() << "Can not specify both " << kAfterClusterTimeFieldName
<< " and " << kAfterOpTimeFieldName);
}
if (_afterClusterTime && _atClusterTime) {
return Status(ErrorCodes::InvalidOptions,
str::stream() << "Can not specify both " << kAfterClusterTimeFieldName
<< " and " << kAtClusterTimeFieldName);
}
// Note: 'available' should not be used with after cluster time, as cluster time can wait for
// replication whereas the premise of 'available' is to avoid waiting. 'linearizable' should not
// be used with after cluster time, since linearizable reads are inherently causally consistent.
if (_afterClusterTime && getLevel() != ReadConcernLevel::kMajorityReadConcern &&
getLevel() != ReadConcernLevel::kLocalReadConcern &&
getLevel() != ReadConcernLevel::kSnapshotReadConcern) {
return Status(ErrorCodes::InvalidOptions,
str::stream()
<< kAfterClusterTimeFieldName << " field can be set only if "
<< kLevelFieldName << " is equal to " << readConcernLevels::kMajorityName
<< ", " << readConcernLevels::kLocalName << ", or "
<< readConcernLevels::kSnapshotName);
}
if (_opTime && getLevel() == ReadConcernLevel::kSnapshotReadConcern) {
return Status(ErrorCodes::InvalidOptions,
str::stream()
<< kAfterOpTimeFieldName << " field cannot be set if " << kLevelFieldName
<< " is equal to " << readConcernLevels::kSnapshotName);
}
if (_atClusterTime && getLevel() != ReadConcernLevel::kSnapshotReadConcern) {
return Status(ErrorCodes::InvalidOptions,
str::stream() << kAtClusterTimeFieldName << " field can be set only if "
<< kLevelFieldName << " is equal to "
<< readConcernLevels::kSnapshotName);
}
// Make sure that atClusterTime wasn't specified with zero seconds.
if (_atClusterTime && _atClusterTime->asTimestamp().isNull()) {
return Status(ErrorCodes::InvalidOptions,
str::stream() << kAtClusterTimeFieldName << " cannot be a null timestamp");
}
// It's okay for afterClusterTime to be specified with zero seconds, but not an uninitialized
// timestamp.
if (_afterClusterTime && _afterClusterTime == LogicalTime::kUninitialized) {
return Status(ErrorCodes::InvalidOptions,
str::stream() << kAfterClusterTimeFieldName << " cannot be a null timestamp");
}
_specified = true;
return Status::OK();
}
ReadConcernArgs ReadConcernArgs::fromBSONThrows(const BSONObj& readConcernObj) {
ReadConcernArgs rc;
uassertStatusOK(rc.parse(readConcernObj));
return rc;
}
void ReadConcernArgs::setMajorityReadMechanism(MajorityReadMechanism mechanism) {
invariant(*_level == ReadConcernLevel::kMajorityReadConcern);
_majorityReadMechanism = mechanism;
}
ReadConcernArgs::MajorityReadMechanism ReadConcernArgs::getMajorityReadMechanism() const {
invariant(*_level == ReadConcernLevel::kMajorityReadConcern);
return _majorityReadMechanism;
}
bool ReadConcernArgs::isSpeculativeMajority() const {
return _level && *_level == ReadConcernLevel::kMajorityReadConcern &&
_majorityReadMechanism == MajorityReadMechanism::kSpeculative;
}
void ReadConcernArgs::appendInfo(BSONObjBuilder* builder) const {
BSONObjBuilder rcBuilder(builder->subobjStart(kReadConcernFieldName));
if (_level) {
rcBuilder.append(kLevelFieldName, readConcernLevels::toString(_level.get()));
}
if (_opTime) {
_opTime->append(&rcBuilder, kAfterOpTimeFieldName.toString());
}
if (_afterClusterTime) {
rcBuilder.append(kAfterClusterTimeFieldName, _afterClusterTime->asTimestamp());
}
if (_atClusterTime) {
rcBuilder.append(kAtClusterTimeFieldName, _atClusterTime->asTimestamp());
}
rcBuilder.done();
}
boost::optional<ReadConcernLevel> readConcernLevels::fromString(StringData levelString) {
if (levelString == readConcernLevels::kLocalName) {
return ReadConcernLevel::kLocalReadConcern;
} else if (levelString == readConcernLevels::kMajorityName) {
return ReadConcernLevel::kMajorityReadConcern;
} else if (levelString == readConcernLevels::kLinearizableName) {
return ReadConcernLevel::kLinearizableReadConcern;
} else if (levelString == readConcernLevels::kAvailableName) {
return ReadConcernLevel::kAvailableReadConcern;
} else if (levelString == readConcernLevels::kSnapshotName) {
return ReadConcernLevel::kSnapshotReadConcern;
} else {
return boost::none;
}
}
StringData readConcernLevels::toString(ReadConcernLevel level) {
switch (level) {
case ReadConcernLevel::kLocalReadConcern:
return kLocalName;
case ReadConcernLevel::kMajorityReadConcern:
return kMajorityName;
case ReadConcernLevel::kLinearizableReadConcern:
return kLinearizableName;
case ReadConcernLevel::kAvailableReadConcern:
return kAvailableName;
case ReadConcernLevel::kSnapshotReadConcern:
return kSnapshotName;
default:
MONGO_UNREACHABLE;
}
}
} // namespace repl
} // namespace mongo
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