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/**
* Copyright (C) 2020-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.
*/
#pragma once
#include "mongo/client/mongo_uri.h"
#include "mongo/client/replica_set_monitor_stats.h"
#include "mongo/client/sdam/sdam.h"
#include "mongo/executor/task_executor.h"
#include "mongo/stdx/unordered_map.h"
#include "mongo/util/net/hostandport.h"
namespace mongo {
using namespace sdam;
class SingleServerDiscoveryMonitor
: public std::enable_shared_from_this<SingleServerDiscoveryMonitor> {
public:
explicit SingleServerDiscoveryMonitor(const MongoURI& setUri,
const HostAndPort& host,
boost::optional<TopologyVersion> topologyVersion,
const SdamConfiguration& sdamConfig,
TopologyEventsPublisherPtr eventListener,
std::shared_ptr<executor::TaskExecutor> executor,
std::shared_ptr<ReplicaSetMonitorStats> stats);
void init();
void shutdown();
/**
* Request an immediate check. The server will be checked immediately if we haven't completed
* a hello less than SdamConfiguration::kMinHeartbeatFrequency ago. Otherwise,
* we schedule a check that runs after SdamConfiguration::kMinHeartbeatFrequency since
* the last hello.
*/
void requestImmediateCheck();
void disableExpeditedChecking();
/**
* Calculates the timing of the next Hello request when moving to expedited mode. Returns
* boost::none if the existing schedule should be maintained.
*/
static boost::optional<Milliseconds> calculateExpeditedDelayUntilNextCheck(
const boost::optional<Milliseconds>& maybeTimeSinceLastCheck,
const Milliseconds& expeditedRefreshPeriod,
const Milliseconds& previousRefreshPeriod);
// Sent in the initial hello request when using the streamable exhaust protocol. The max
// duration a server should wait for a significant topology change before sending a response.
static constexpr Milliseconds kMaxAwaitTime = Milliseconds(10000);
private:
void _scheduleNextHello(WithLock, Milliseconds delay);
void _rescheduleNextHello(WithLock, Milliseconds delay);
void _doRemoteCommand();
// Use the awaitable hello protocol with the exhaust bit set. Attach _topologyVersion and
// kMaxAwaitTimeMS to the request.
StatusWith<executor::TaskExecutor::CallbackHandle> _scheduleStreamableHello();
// Use the old hello protocol. Do not attach _topologyVersion or kMaxAwaitTimeMS to the
// request.
StatusWith<executor::TaskExecutor::CallbackHandle> _scheduleSingleHello();
void _onHelloSuccess(BSONObj bson);
void _onHelloFailure(const Status& status, BSONObj bson);
Milliseconds _overrideRefreshPeriod(Milliseconds original);
Milliseconds _currentRefreshPeriod(WithLock, bool scheduleImmediately);
void _cancelOutstandingRequest(WithLock);
boost::optional<Milliseconds> _timeSinceLastCheck() const;
static constexpr auto kLogLevel = 0;
const HostAndPort _host;
const std::shared_ptr<ReplicaSetMonitorStats> _stats;
Mutex _mutex =
MONGO_MAKE_LATCH(HierarchicalAcquisitionLevel(4), "SingleServerDiscoveryMonitor::mutex");
boost::optional<TopologyVersion> _topologyVersion;
TopologyEventsPublisherPtr _eventListener;
std::shared_ptr<executor::TaskExecutor> _executor;
Milliseconds _heartbeatFrequency;
Milliseconds _connectTimeout;
boost::optional<Date_t> _lastHelloAt;
bool _helloOutstanding = false;
bool _isExpedited;
executor::TaskExecutor::CallbackHandle _nextHelloHandle;
executor::TaskExecutor::CallbackHandle _remoteCommandHandle;
bool _isShutdown;
MongoURI _setUri;
};
using SingleServerDiscoveryMonitorPtr = std::shared_ptr<SingleServerDiscoveryMonitor>;
class ServerDiscoveryMonitor : public TopologyListener {
public:
ServerDiscoveryMonitor(const MongoURI& setUri,
const SdamConfiguration& sdamConfiguration,
TopologyEventsPublisherPtr eventsPublisher,
TopologyDescriptionPtr initialTopologyDescription,
std::shared_ptr<ReplicaSetMonitorStats> stats,
std::shared_ptr<executor::TaskExecutor> executor = nullptr);
virtual ~ServerDiscoveryMonitor() {}
void shutdown();
/**
* Request an immediate check of each member in the replica set.
*/
void requestImmediateCheck();
/**
* Add/Remove Single Monitors based on the current topology membership.
*/
void onTopologyDescriptionChangedEvent(TopologyDescriptionPtr previousDescription,
TopologyDescriptionPtr newDescription) override;
void disableExpeditedChecking();
private:
/**
* If the provided executor exists, use that one (for testing). Otherwise create a new one.
*/
std::shared_ptr<executor::TaskExecutor> _setupExecutor(
const std::shared_ptr<executor::TaskExecutor>& executor);
void _disableExpeditedChecking(WithLock);
static constexpr auto kLogLevel = 0;
const std::shared_ptr<ReplicaSetMonitorStats> _stats;
Mutex _mutex =
MONGO_MAKE_LATCH(HierarchicalAcquisitionLevel(5), "ServerDiscoveryMonitor::mutex");
SdamConfiguration _sdamConfiguration;
TopologyEventsPublisherPtr _eventPublisher;
std::shared_ptr<executor::TaskExecutor> _executor;
stdx::unordered_map<HostAndPort, SingleServerDiscoveryMonitorPtr> _singleMonitors;
bool _isShutdown;
MongoURI _setUri;
};
using ServerDiscoveryMonitorPtr = std::shared_ptr<ServerDiscoveryMonitor>;
} // namespace mongo
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