61 lines
2.4 KiB
C
61 lines
2.4 KiB
C
/*
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* Copyright (c) 2019 TAOS Data, Inc. <cli@taosdata.com>
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*
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* This program is free software: you can use, redistribute, and/or modify
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* it under the terms of the GNU Affero General Public License, version 3
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* or later ("AGPL"), as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE.
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*
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* You should have received a copy of the GNU Affero General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include "syncInt.h"
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#include "raft.h"
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#include "sync_raft_impl.h"
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#include "raft_log.h"
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#include "raft_message.h"
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static bool canGrantVoteMessage(SSyncRaft* pRaft, const SSyncMessage* pMsg);
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int syncRaftHandleVoteMessage(SSyncRaft* pRaft, const SSyncMessage* pMsg) {
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SSyncMessage* pRespMsg;
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SNodeInfo* pNode = syncRaftGetNodeById(pRaft, pMsg->from);
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if (pNode == NULL) {
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return 0;
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}
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bool grant;
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SyncIndex lastIndex = syncRaftLogLastIndex(pRaft->log);
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SyncTerm lastTerm = syncRaftLogLastTerm(pRaft->log);
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grant = canGrantVoteMessage(pRaft, pMsg);
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pRespMsg = syncNewVoteRespMsg(pRaft->selfGroupId, pRaft->selfId, pMsg->vote.cType, !grant);
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if (pRespMsg == NULL) {
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return 0;
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}
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syncInfo("[%d:%d] [logterm: %" PRId64 ", index: %" PRId64 ", vote: %d] %s for %d"\
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"[logterm: %" PRId64 ", index: %" PRId64 "] at term %" PRId64 "",
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pRaft->selfGroupId, pRaft->selfId, lastTerm, lastIndex, pRaft->voteFor,
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grant ? "grant" : "reject",
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pMsg->from, pMsg->vote.lastTerm, pMsg->vote.lastIndex, pRaft->term);
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pRaft->io.send(pRespMsg, pNode);
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return 0;
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}
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static bool canGrantVoteMessage(SSyncRaft* pRaft, const SSyncMessage* pMsg) {
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bool canVote =
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// We can vote if this is a repeat of a vote we've already cast...
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pRaft->voteFor == pMsg->from ||
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// ...we haven't voted and we don't think there's a leader yet in this term...
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(pRaft->voteFor == SYNC_NON_NODE_ID && pRaft->leaderId == SYNC_NON_NODE_ID) ||
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// ...or this is a PreVote for a future term...
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(pMsg->vote.cType == SYNC_RAFT_CAMPAIGN_PRE_ELECTION && pMsg->term > pRaft->term);
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// ...and we believe the candidate is up to date.
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return canVote && syncRaftLogIsUptodate(pRaft->log, pMsg->vote.lastIndex, pMsg->vote.lastTerm);
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} |