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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.
*/
#pragma once
#include "mongo/base/disallow_copying.h"
#include "mongo/util/periodic_runner.h"
namespace mongo {
class OperationContext;
class ServiceContext;
class PeriodicBalancerConfigRefresher final {
MONGO_DISALLOW_COPYING(PeriodicBalancerConfigRefresher);
public:
PeriodicBalancerConfigRefresher() = default;
~PeriodicBalancerConfigRefresher() = default;
PeriodicBalancerConfigRefresher(PeriodicBalancerConfigRefresher&& source) = delete;
PeriodicBalancerConfigRefresher& operator=(PeriodicBalancerConfigRefresher&& other) = delete;
/**
* Obtains the service-wide chunk PeriodicBalancerConfigRefresher instance.
*/
static PeriodicBalancerConfigRefresher& get(OperationContext* opCtx);
static PeriodicBalancerConfigRefresher& get(ServiceContext* serviceContext);
/**
* Sets the mode to either primary or secondary. If it is primary, starts a
* periodic task to refresh the balancer configuration. The
* PeriodicBalancerConfigRefresher is only active when primary.
*/
void onShardingInitialization(ServiceContext* serviceContext, bool isPrimary);
/**
* Invoked when the shard server primary enters the 'PRIMARY' state to
* trigger the start of the periodic refresh task.
*/
void onStepUp(ServiceContext* serviceContext);
/**
* Invoked when this node which is currently serving as a 'PRIMARY' steps down.
*
* Pauses the periodic refresh until subsequent step up. This method might
* be called multiple times in succession, which is what happens as a
* result of incomplete transition to primary so it is resilient to that.
*/
void onStepDown();
private:
bool _isPrimary{false};
// Periodic job for refreshing the balancer configuration
std::unique_ptr<PeriodicRunner::PeriodicJobHandle> _balancerConfigRefresher;
};
} // namespace mongo
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