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/**
* Copyright (C) 2019-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::kNetwork
#include "mongo/client/sdam/topology_manager.h"
#include "mongo/client/sdam/topology_state_machine.h"
#include "mongo/logv2/log.h"
namespace mongo::sdam {
namespace {
/* Compare topologyVersions to determine if the isMaster response's topologyVersion is stale
* according to the following rules:
* 1. If the response's topologyVersion is unset or the lastServerDescription's topologyVersion is
* null, the client MUST assume the response is more recent.
* 2. If the response’s topologyVersion.processId != to lastServerDescription's, the client MUST
* assume the response is more recent.
* 3. If the response’s topologyVersion.processId == to lastServerDescription's and response's
* topologyVersion.counter < lastServerDescription's topologyVersion.counter, the client MUST ignore
* this reply because the lastServerDescription is fresher.
*/
bool isStaleTopologyVersion(boost::optional<TopologyVersion> lastTopologyVersion,
boost::optional<TopologyVersion> newTopologyVersion) {
if (lastTopologyVersion && newTopologyVersion &&
((lastTopologyVersion->getProcessId() == newTopologyVersion->getProcessId()) &&
(lastTopologyVersion->getCounter() > newTopologyVersion->getCounter()))) {
return true;
}
return false;
}
} // namespace
TopologyManager::TopologyManager(SdamConfiguration config, ClockSource* clockSource)
: _config(std::move(config)),
_clockSource(clockSource),
_topologyDescription(std::make_unique<TopologyDescription>(_config)),
_topologyStateMachine(std::make_unique<TopologyStateMachine>(_config)) {}
void TopologyManager::onServerDescription(const IsMasterOutcome& isMasterOutcome) {
stdx::lock_guard<mongo::Mutex> lock(_mutex);
boost::optional<IsMasterRTT> lastRTT;
boost::optional<TopologyVersion> lastTopologyVersion;
boost::optional<int> lastPoolResetCounter;
const auto& lastServerDescription =
_topologyDescription->findServerByAddress(isMasterOutcome.getServer());
if (lastServerDescription) {
lastRTT = (*lastServerDescription)->getRtt();
lastTopologyVersion = (*lastServerDescription)->getTopologyVersion();
lastPoolResetCounter = (*lastServerDescription)->getPoolResetCounter();
}
boost::optional<TopologyVersion> newTopologyVersion = isMasterOutcome.getTopologyVersion();
if (isStaleTopologyVersion(lastTopologyVersion, newTopologyVersion)) {
LOGV2(
23930,
"Ignoring this isMaster response because our topologyVersion: {lastTopologyVersion}is "
"fresher than the provided topologyVersion: {newTopologyVersion}",
"lastTopologyVersion"_attr = lastTopologyVersion->toBSON(),
"newTopologyVersion"_attr = newTopologyVersion->toBSON());
return;
}
boost::optional<int> poolResetCounter = lastPoolResetCounter;
if (!isMasterOutcome.isSuccess() && lastPoolResetCounter) {
// Bump the poolResetCounter on error if we have one established already.
poolResetCounter = ++lastPoolResetCounter.get();
}
// newTopologyVersion will be null if the isMaster response did not provide one.
auto newServerDescription = std::make_shared<ServerDescription>(
_clockSource, isMasterOutcome, lastRTT, newTopologyVersion, poolResetCounter);
auto newTopologyDescription = std::make_unique<TopologyDescription>(*_topologyDescription);
_topologyStateMachine->onServerDescription(*newTopologyDescription, newServerDescription);
_topologyDescription = std::move(newTopologyDescription);
}
const std::shared_ptr<TopologyDescription> TopologyManager::getTopologyDescription() const {
stdx::lock_guard<mongo::Mutex> lock(_mutex);
return _topologyDescription;
}
}; // namespace mongo::sdam
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