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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/util/time_support.h"
namespace mongo {
namespace repl {
/**
* Description of actions taken in response to a heartbeat.
*
* This includes when to schedule the next heartbeat to a target, and any other actions to
* take, such as scheduling an election or stepping down as primary.
*/
class HeartbeatResponseAction {
public:
/**
* Actions taken based on heartbeat responses
*/
enum Action {
NoAction,
Reconfig,
StepDownSelf,
PriorityTakeover,
CatchupTakeover,
RetryReconfig
};
/**
* Makes a new action representing doing nothing.
*/
static HeartbeatResponseAction makeNoAction();
/**
* Makes a new action representing the instruction to reconfigure the current node.
*/
static HeartbeatResponseAction makeReconfigAction();
/**
* Makes a new action telling the current node to schedule an event to attempt to elect itself
* primary after the appropriate priority takeover delay.
*/
static HeartbeatResponseAction makePriorityTakeoverAction();
/**
* Makes a new action telling the current node to schedule an event to attempt to elect itself
* primary after the appropriate catchup takeover delay.
*/
static HeartbeatResponseAction makeCatchupTakeoverAction();
/**
* Makes a new action telling the current node to attempt to find itself in its current replica
* set config again, in case the previous attempt's failure was due to a temporary DNS outage.
*/
static HeartbeatResponseAction makeRetryReconfigAction();
/**
* Makes a new action telling the current node to step down as primary.
*
* It is an error to call this with primaryIndex != the index of the current node.
*/
static HeartbeatResponseAction makeStepDownSelfAction(int primaryIndex);
/**
* Construct an action with unspecified action and a next heartbeat start date in the
* past.
*/
HeartbeatResponseAction();
/**
* Sets the date at which the next heartbeat should be scheduled.
*/
void setNextHeartbeatStartDate(Date_t when);
/**
* Sets whether or not the heartbeat response advanced the member's opTime.
*/
void setAdvancedOpTime(bool advanced);
/*
* Sets whether or not the member has transitioned from unelectable to electable since the last
* heartbeat response.
*/
void setBecameElectable(bool becameElectable);
/**
* Gets the action type of this action.
*/
Action getAction() const {
return _action;
}
/**
* Gets the time at which the next heartbeat should be scheduled. If the
* time is not in the future, the next heartbeat should be scheduled immediately.
*/
Date_t getNextHeartbeatStartDate() const {
return _nextHeartbeatStartDate;
}
/**
* If getAction() returns StepDownSelf or StepDownPrimary, this is the index
* in the current replica set config of the node that ought to step down.
*/
int getPrimaryConfigIndex() const {
return _primaryIndex;
}
/*
* Returns true if the heartbeat response resulting in our conception of the
* member's optime moving forward, so we need to recalculate lastCommittedOpTime.
*/
bool getAdvancedOpTime() const {
return _advancedOpTime;
}
/*
* Returns true if the heartbeat response results in the member transitioning from unelectable
* to electable.
*/
bool getBecameElectable() const {
return _becameElectable;
}
private:
Action _action;
int _primaryIndex;
Date_t _nextHeartbeatStartDate;
bool _advancedOpTime = false;
bool _becameElectable = false;
};
} // namespace repl
} // namespace mongo
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