homework-jianmu/source/libs/sync/inc/raft.h

146 lines
3.7 KiB
C

/*
* Copyright (c) 2019 TAOS Data, Inc. <cli@taosdata.com>
*
* This program is free software: you can use, redistribute, and/or modify
* it under the terms of the GNU Affero General Public License, version 3
* or later ("AGPL"), as published by the Free Software Foundation.
*
* 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.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#ifndef _TD_LIBS_SYNC_RAFT_H
#define _TD_LIBS_SYNC_RAFT_H
#include "sync.h"
#include "sync_type.h"
#include "thash.h"
#include "raft_message.h"
#include "sync_raft_impl.h"
#include "sync_raft_quorum.h"
typedef struct RaftLeaderState {
} RaftLeaderState;
typedef struct RaftCandidateState {
/* true if in pre-vote phase */
bool inPreVote;
} RaftCandidateState;
typedef struct SSyncRaftIOMethods {
// send SSyncMessage to node
int (*send)(const SSyncMessage* pMsg, const SNodeInfo* pNode);
} SSyncRaftIOMethods;
typedef int (*SyncRaftStepFp)(SSyncRaft* pRaft, const SSyncMessage* pMsg);
typedef void (*SyncRaftTickFp)(SSyncRaft* pRaft);
struct SSyncRaft {
// owner sync node
SSyncNode* pNode;
// hash map nodeId -> SNodeInfo*
SHashObj* nodeInfoMap;
SyncNodeId selfId;
SyncGroupId selfGroupId;
SSyncRaftIOMethods io;
SSyncFSM fsm;
SSyncLogStore logStore;
SStateManager stateManager;
union {
RaftLeaderState leaderState;
RaftCandidateState candidateState;
};
SyncTerm term;
SyncNodeId voteFor;
SSyncRaftLog *log;
uint64_t maxMsgSize;
uint64_t maxUncommittedSize;
SSyncRaftProgressTracker *tracker;
ESyncState state;
// isLearner is true if the local raft node is a learner.
bool isLearner;
/**
* the leader id
**/
SyncNodeId leaderId;
/**
* leadTransferee is id of the leader transfer target when its value is not zero.
* Follow the procedure defined in raft thesis 3.10.
**/
SyncNodeId leadTransferee;
/**
* Only one conf change may be pending (in the log, but not yet
* applied) at a time. This is enforced via pendingConfIndex, which
* is set to a value >= the log index of the latest pending
* configuration change (if any). Config changes are only allowed to
* be proposed if the leader's applied index is greater than this
* value.
**/
SyncIndex pendingConfigIndex;
/**
* an estimate of the size of the uncommitted tail of the Raft log. Used to
* prevent unbounded log growth. Only maintained by the leader. Reset on
* term changes.
**/
uint32_t uncommittedSize;
/**
* number of ticks since it reached last electionTimeout when it is leader
* or candidate.
* number of ticks since it reached last electionTimeout or received a
* valid message from current leader when it is a follower.
**/
uint16_t electionElapsed;
/**
* number of ticks since it reached last heartbeatTimeout.
* only leader keeps heartbeatElapsed.
**/
uint16_t heartbeatElapsed;
bool preVote;
bool checkQuorum;
int heartbeatTimeout;
int electionTimeout;
/**
* randomizedElectionTimeout is a random number between
* [electiontimeout, 2 * electiontimeout - 1]. It gets reset
* when raft changes its state to follower or candidate.
**/
int randomizedElectionTimeout;
bool disableProposalForwarding;
// current tick count since start up
uint32_t currentTick;
SyncRaftStepFp stepFp;
SyncRaftTickFp tickFp;
};
int32_t syncRaftStart(SSyncRaft* pRaft, const SSyncInfo* pInfo);
int32_t syncRaftStep(SSyncRaft* pRaft, const SSyncMessage* pMsg);
int32_t syncRaftTick(SSyncRaft* pRaft);
#endif /* _TD_LIBS_SYNC_RAFT_H */