[TD-10645][raft]<feature>add raft append message handle

source/libs/sync/inc/raft.h

@@ -20,8 +20,6 @@
 #include "sync_type.h"
 #include "raft_message.h"
 
-#define SYNC_NON_NODE_ID -1
-
 typedef struct SSyncRaftProgress SSyncRaftProgress;
 
 typedef struct RaftLeaderState {
@@ -49,7 +47,8 @@ struct SSyncRaft {
   // owner sync node
   SSyncNode* pNode;
 
-  //SSyncInfo info;
+  int maxMsgSize;
+
   SSyncFSM      fsm;
   SSyncLogStore logStore;
   SStateManager stateManager;
@@ -74,7 +73,7 @@ struct SSyncRaft {
 	/** 
    * New configuration is ignored if there exists unapplied configuration.
    **/
-	bool pendingConf;
+	bool hasPendingConf;
 
   SSyncCluster cluster;
 
@@ -94,6 +93,9 @@ struct SSyncRaft {
    **/
   uint16_t heartbeatElapsed;
 
+  // current tick count since start up
+  uint32_t currentTick;
+
   // election timeout tick(random in [3:6] tick)
   uint16_t electionTimeoutTick;
 
@@ -129,7 +131,7 @@ void syncRaftBecomeLeader(SSyncRaft* pRaft);
 
 void syncRaftStartElection(SSyncRaft* pRaft, SyncRaftElectionType cType);
 
-void syncRaftTriggerReplicate(SSyncRaft* pRaft);
+void syncRaftTriggerHeartbeat(SSyncRaft* pRaft);
 
 void syncRaftRandomizedElectionTimeout(SSyncRaft* pRaft);
 bool syncRaftIsPromotable(SSyncRaft* pRaft);

source/libs/sync/inc/raft_log.h

@@ -19,6 +19,10 @@
 #include "sync.h"
 #include "sync_type.h"
 
+struct SSyncRaftEntry {
+
+};
+
 struct SSyncRaftLog {
   SyncIndex uncommittedConfigIndex;
 
@@ -41,4 +45,9 @@ int syncRaftLogNumOfPendingConf(SSyncRaftLog* pLog);
 
 bool syncRaftHasUnappliedLog(SSyncRaftLog* pLog);
 
+SyncTerm syncRaftLogTermOf(SSyncRaftLog* pLog, SyncIndex index);
+
+int syncRaftLogAcquire(SSyncRaftLog* pLog, SyncIndex index, int maxMsgSize,
+                      SSyncRaftEntry **ppEntries, int *n);
+
 #endif  /* _TD_LIBS_SYNC_RAFT_LOG_H */

source/libs/sync/inc/raft_message.h

@@ -63,12 +63,28 @@ typedef struct RaftMsg_VoteResp {
   SyncRaftElectionType cType;
 } RaftMsg_VoteResp;
 
+typedef struct RaftMsg_Append_Entries {
+  // index of log entry preceeding new ones
+  SyncIndex prevIndex;
+
+  // term of entry at prevIndex
+  SyncTerm prevTerm;
+
+  // leader's commit index.
+  SyncIndex commitIndex;
+
+  // size of the log entries array
+  int nEntries;
+
+  // log entries array
+  SSyncRaftEntry* entries;
+} RaftMsg_Append_Entries;
+
 typedef struct SSyncMessage {
   RaftMessageType msgType;
   SyncTerm term;
   SyncGroupId groupId;
   SyncNodeId from;
-  SyncNodeId to;
 
   union {
     RaftMsgInternal_Prop propose;
@@ -77,6 +93,8 @@ typedef struct SSyncMessage {
 
     RaftMsg_Vote vote;
     RaftMsg_VoteResp voteResp;
+
+    RaftMsg_Append_Entries appendEntries;
   };
 } SSyncMessage;
 
@@ -107,7 +125,7 @@ static FORCE_INLINE SSyncMessage* syncInitElectionMsg(SSyncMessage* pMsg, SyncNo
   return pMsg;
 }
 
-static FORCE_INLINE SSyncMessage* syncNewVoteMsg(SyncGroupId groupId, SyncNodeId from, SyncNodeId to,
+static FORCE_INLINE SSyncMessage* syncNewVoteMsg(SyncGroupId groupId, SyncNodeId from,
                                                 SyncTerm term, SyncRaftElectionType cType, 
                                                 SyncIndex lastIndex, SyncTerm lastTerm) {
   SSyncMessage* pMsg = (SSyncMessage*)malloc(sizeof(SSyncMessage));
@@ -117,7 +135,6 @@ static FORCE_INLINE SSyncMessage* syncNewVoteMsg(SyncGroupId groupId, SyncNodeId
   *pMsg = (SSyncMessage) {
     .groupId = groupId,
     .from = from,
-    .to = to,
     .term = term,
     .msgType = RAFT_MSG_VOTE,
     .vote = (RaftMsg_Vote) {
@@ -130,7 +147,7 @@ static FORCE_INLINE SSyncMessage* syncNewVoteMsg(SyncGroupId groupId, SyncNodeId
   return pMsg;
 }
 
-static FORCE_INLINE SSyncMessage* syncNewVoteRespMsg(SyncGroupId groupId, SyncNodeId from, SyncNodeId to,
+static FORCE_INLINE SSyncMessage* syncNewVoteRespMsg(SyncGroupId groupId, SyncNodeId from,
                                                   SyncRaftElectionType cType, bool rejected) {
   SSyncMessage* pMsg = (SSyncMessage*)malloc(sizeof(SSyncMessage));
   if (pMsg == NULL) {
@@ -139,7 +156,6 @@ static FORCE_INLINE SSyncMessage* syncNewVoteRespMsg(SyncGroupId groupId, SyncNo
   *pMsg = (SSyncMessage) {
     .groupId = groupId,
     .from = from,
-    .to = to,
     .msgType = RAFT_MSG_VOTE_RESP,
     .voteResp = (RaftMsg_VoteResp) {
       .cType = cType,
@@ -150,12 +166,36 @@ static FORCE_INLINE SSyncMessage* syncNewVoteRespMsg(SyncGroupId groupId, SyncNo
   return pMsg;
 }
 
+static FORCE_INLINE SSyncMessage* syncNewAppendMsg(SyncGroupId groupId, SyncNodeId from,
+                                                  SyncTerm term, SyncIndex prevIndex, SyncTerm prevTerm,
+                                                  SyncIndex commitIndex, int nEntries, SSyncRaftEntry* entries) {
+  SSyncMessage* pMsg = (SSyncMessage*)malloc(sizeof(SSyncMessage));
+  if (pMsg == NULL) {
+    return NULL;
+  }
+  *pMsg = (SSyncMessage) {
+    .groupId = groupId,
+    .from = from,
+    .term = term,
+    .msgType = RAFT_MSG_APPEND,
+    .appendEntries = (RaftMsg_Append_Entries) {
+      .prevIndex = prevIndex,
+      .prevTerm = prevTerm,
+      .commitIndex = commitIndex,
+      .nEntries = nEntries,
+      .entries = entries,
+    },
+  };
+
+  return pMsg;
+}
+
 static FORCE_INLINE bool syncIsInternalMsg(RaftMessageType msgType) {
   return msgType == RAFT_MSG_INTERNAL_PROP ||
          msgType == RAFT_MSG_INTERNAL_ELECTION;
 }
 
-static FORCE_INLINE bool syncIsPreVoteRespMsg(SSyncMessage* pMsg) {
+static FORCE_INLINE bool syncIsPreVoteRespMsg(const SSyncMessage* pMsg) {
   return pMsg->msgType == RAFT_MSG_VOTE_RESP && pMsg->voteResp.cType == SYNC_RAFT_CAMPAIGN_PRE_ELECTION;
 }
 

source/libs/sync/inc/raft_progress.h

@@ -85,6 +85,9 @@ struct SSyncRaftProgress {
    **/ 
   bool paused;
 
+  // last send append message tick
+  uint32_t lastSendTick;
+
 	/** 
    * pendingSnapshotIndex is used in PROGRESS_SNAPSHOT.
 	 * If there is a pending snapshot, the pendingSnapshotIndex will be set to the
@@ -116,7 +119,9 @@ int syncRaftProgressCreate(SSyncRaft* pRaft);
  **/
 bool syncRaftProgressMaybeUpdate(SSyncRaft* pRaft, int i, SyncIndex lastIndex);
 
-void syncRaftProgressOptimisticNextIndex(SSyncRaft* pRaft, int i, SyncIndex nextIndex);
+static FORCE_INLINE void syncRaftProgressOptimisticNextIndex(SSyncRaftProgress* progress, SyncIndex nextIndex) {
+  progress->nextIndex = nextIndex + 1;
+}
 
 /** 
  * syncRaftProgressMaybeDecrTo returns false if the given to index comes from an out of order message.
@@ -131,7 +136,35 @@ bool syncRaftProgressMaybeDecrTo(SSyncRaft* pRaft, int i,
  * MsgApps, is currently waiting for a snapshot, or has reached the
  * MaxInflightMsgs limit.
  **/
-bool syncRaftProgressIsPaused(SSyncRaft* pRaft, int i);
+bool syncRaftProgressIsPaused(SSyncRaftProgress* progress);
+
+static FORCE_INLINE void syncRaftProgressPause(SSyncRaftProgress* progress) {
+  progress->paused = true;
+}
+
+static FORCE_INLINE SyncIndex syncRaftProgressNextIndex(SSyncRaftProgress* progress) {
+  return progress->nextIndex;
+}
+
+static FORCE_INLINE RaftProgressState syncRaftProgressInReplicate(SSyncRaftProgress* progress) {
+  return progress->state == PROGRESS_REPLICATE;
+}
+
+static FORCE_INLINE RaftProgressState syncRaftProgressInSnapshot(SSyncRaftProgress* progress) {
+  return progress->state == PROGRESS_SNAPSHOT;
+}
+
+static FORCE_INLINE RaftProgressState syncRaftProgressInProbe(SSyncRaftProgress* progress) {
+  return progress->state == PROGRESS_PROBE;
+}
+
+static FORCE_INLINE bool syncRaftProgressRecentActive(SSyncRaftProgress* progress) {
+  return progress->recentActive;
+}
+
+static FORCE_INLINE bool syncRaftProgressUpdateSendTick(SSyncRaftProgress* progress, SyncTick current) {
+  return progress->lastSendTick = current;
+}
 
 void syncRaftProgressFailure(SSyncRaft* pRaft, int i);
 
@@ -159,7 +192,7 @@ void syncRaftInflightFreeFirstOne(SSyncRaftInflights* inflights);
 
 void syncRaftProgressAbortSnapshot(SSyncRaft* pRaft, int i);
 
-SyncIndex syncRaftProgressNextIndex(SSyncRaft* pRaft, int i);
+
 
 SyncIndex syncRaftProgressMatchIndex(SSyncRaft* pRaft, int i);
 
@@ -171,11 +204,9 @@ bool syncRaftProgressResetRecentRecv(SSyncRaft* pRaft, int i);
 
 void syncRaftProgressMarkRecentRecv(SSyncRaft* pRaft, int i);
 
-bool syncRaftProgressGetRecentRecv(SSyncRaft* pRaft, int i);
 
-void syncRaftProgressAbortSnapshot(SSyncRaft* pRaft, int i);
 
-RaftProgressState syncRaftProgressState(SSyncRaft* pRaft, int i);
+void syncRaftProgressAbortSnapshot(SSyncRaft* pRaft, int i);
 
 #endif
 

source/libs/sync/inc/raft_replication.h

+/*
+ * 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_SYNC_RAFT_REPLICATION_H
+#define TD_SYNC_RAFT_REPLICATION_H
+
+#include "sync.h"
+#include "syncInt.h"
+#include "sync_type.h"
+
+int syncRaftReplicate(SSyncRaft* pRaft, int i);
+
+#endif  /* TD_SYNC_RAFT_REPLICATION_H */

source/libs/sync/inc/sync_type.h

@@ -16,12 +16,18 @@
 #ifndef _TD_LIBS_SYNC_TYPE_H
 #define _TD_LIBS_SYNC_TYPE_H
 
+#define SYNC_NON_NODE_ID -1
+#define SYNC_NON_TERM     0
+
 typedef int32_t SyncTime;
+typedef uint32_t SyncTick;
 
 typedef struct SSyncRaft SSyncRaft;
 
 typedef struct SSyncRaftLog SSyncRaftLog;
 
+typedef struct SSyncRaftEntry SSyncRaftEntry;
+
 #ifndef MIN
 #define MIN(x, y) (((x) < (y)) ? (x) : (y))
 #endif
@@ -32,13 +38,18 @@ typedef struct SSyncRaftLog SSyncRaftLog;
 
 typedef enum {
   SYNC_RAFT_CAMPAIGN_PRE_ELECTION = 0,
-  SYNC_RAFT_CAMPAIGN_ELECTION = 1,
-  SYNC_RAFT_CAMPAIGN_TRANSFER = 3,
+  SYNC_RAFT_CAMPAIGN_ELECTION     = 1,
+  SYNC_RAFT_CAMPAIGN_TRANSFER     = 2,
 } SyncRaftElectionType;
 
 typedef enum {
+  // the init vote resp status
   SYNC_RAFT_VOTE_RESP_UNKNOWN = 0,
+
+  // grant the vote request
   SYNC_RAFT_VOTE_RESP_GRANT   = 1,
+
+  //reject the vote request
   SYNC_RAFT_VOTE_RESP_REJECT  = 2,
 } SyncRaftVoteRespType;
 

source/libs/sync/src/raft.c

@@ -29,6 +29,8 @@ static int stepFollower(SSyncRaft* pRaft, const SSyncMessage* pMsg);
 static int stepCandidate(SSyncRaft* pRaft, const SSyncMessage* pMsg);
 static int stepLeader(SSyncRaft* pRaft, const SSyncMessage* pMsg);
 
+static int triggerAll(SSyncRaft* pRaft);
+
 static void tickElection(SSyncRaft* pRaft);
 static void tickHeartbeat(SSyncRaft* pRaft);
 
@@ -95,8 +97,8 @@ int32_t syncRaftStart(SSyncRaft* pRaft, const SSyncInfo* pInfo) {
 }
 
 int32_t syncRaftStep(SSyncRaft* pRaft, const SSyncMessage* pMsg) {
-  syncDebug("from %d, to %d, type:%d, term:%" PRId64 ", state:%d",
-    pMsg->from, pMsg->to, pMsg->msgType, pMsg->term, pRaft->state);
+  syncDebug("from %d, type:%d, term:%" PRId64 ", state:%d",
+    pMsg->from, pMsg->msgType, pMsg->term, pRaft->state);
 
   if (preHandleMessage(pRaft, pMsg)) {
     syncFreeMessage(pMsg);
@@ -117,6 +119,7 @@ int32_t syncRaftStep(SSyncRaft* pRaft, const SSyncMessage* pMsg) {
 }
 
 int32_t syncRaftTick(SSyncRaft* pRaft) {
+  pRaft->currentTick += 1;
   return 0;
 }
 
@@ -168,12 +171,22 @@ void syncRaftBecomeLeader(SSyncRaft* pRaft) {
   pRaft->leaderId = pRaft->leaderId;
   pRaft->state  = TAOS_SYNC_ROLE_LEADER;
   // TODO: check if there is pending config log
+  int nPendingConf = syncRaftLogNumOfPendingConf(pRaft->log);
+  if (nPendingConf > 1) {
+    syncFatal("unexpected multiple uncommitted config entry");
+  }
+  if (nPendingConf == 1) {
+    pRaft->hasPendingConf = true;
+  }
 
   syncInfo("[%d:%d] became leader at term %" PRId64 "", pRaft->selfGroupId, pRaft->selfId, pRaft->term);
-}
 
-void syncRaftTriggerReplicate(SSyncRaft* pRaft) {
+  // after become leader, send initial heartbeat
+  syncRaftTriggerHeartbeat(pRaft);
+}
 
+void syncRaftTriggerHeartbeat(SSyncRaft* pRaft) {
+  triggerAll(pRaft);
 }
 
 void syncRaftRandomizedElectionTimeout(SSyncRaft* pRaft) {
@@ -219,7 +232,7 @@ int syncRaftNumOfGranted(SSyncRaft* pRaft, SyncNodeId id, bool preVote, bool acc
 }
 
 /**
- * pre-handle message, return true is no need to continue
+ * pre-handle message, return true means no need to continue
  * Handle the message term, which may result in our stepping down to a follower.
  **/
 static bool preHandleMessage(SSyncRaft* pRaft, const SSyncMessage* pMsg) {
@@ -230,9 +243,11 @@ static bool preHandleMessage(SSyncRaft* pRaft, const SSyncMessage* pMsg) {
 
   if (pMsg->term > pRaft->term) {
     return preHandleNewTermMessage(pRaft, pMsg);
+  } else if (pMsg->term < pRaft->term) {
+    return preHandleOldTermMessage(pRaft, pMsg);
   }
 
-  return preHandleOldTermMessage(pRaft, pMsg);;
+  return false;
 }
 
 static bool preHandleNewTermMessage(SSyncRaft* pRaft, const SSyncMessage* pMsg) {
@@ -240,6 +255,7 @@ static bool preHandleNewTermMessage(SSyncRaft* pRaft, const SSyncMessage* pMsg)
   RaftMessageType msgType = pMsg->msgType;
 
   if (msgType == RAFT_MSG_VOTE) {
+    // TODO
     leaderId = SYNC_NON_NODE_ID;
   }
 
@@ -263,7 +279,7 @@ static bool preHandleNewTermMessage(SSyncRaft* pRaft, const SSyncMessage* pMsg)
 }
 
 static bool preHandleOldTermMessage(SSyncRaft* pRaft, const SSyncMessage* pMsg) {
-
+  // TODO
   // if receive old term message, no need to continue
   return true;
 }
@@ -273,7 +289,7 @@ static int convertClear(SSyncRaft* pRaft) {
 }
 
 static int stepFollower(SSyncRaft* pRaft, const SSyncMessage* pMsg) {
-  convertClear(pRaft);
+  
   return 0;
 }
 
@@ -290,6 +306,7 @@ static int stepCandidate(SSyncRaft* pRaft, const SSyncMessage* pMsg) {
   }
 
   if (msgType == RAFT_MSG_VOTE_RESP) {
+    syncRaftHandleVoteRespMessage(pRaft, pMsg);
     return 0;
   }
   return 0;
@@ -324,6 +341,22 @@ static void tickHeartbeat(SSyncRaft* pRaft) {
 
 }
 
+/**
+ * trigger I/O requests for newly appended log entries or heartbeats.
+ **/
+static int triggerAll(SSyncRaft* pRaft) {
+  assert(pRaft->state == TAOS_SYNC_ROLE_LEADER);
+  int i;
+
+  for (i = 0; i < pRaft->cluster.replica; ++i) {
+    if (i == pRaft->cluster.selfIndex) {
+      continue;
+    }
+
+    
+  }
+}
+
 static void abortLeaderTransfer(SSyncRaft* pRaft) {
   pRaft->leadTransferee = SYNC_NON_NODE_ID;
 }
@@ -343,5 +376,5 @@ static void resetRaft(SSyncRaft* pRaft, SyncTerm term) {
 
   abortLeaderTransfer(pRaft);
 
-  pRaft->pendingConf = false;
-}
\ No newline at end of file
+  pRaft->hasPendingConf = false;
+}

source/libs/sync/src/raft_election.c

@@ -62,7 +62,7 @@ void syncRaftStartElection(SSyncRaft* pRaft, SyncRaftElectionType cType) {
     SyncNodeId nodeId = pRaft->cluster.nodeInfo[i].nodeId;
 
     SSyncMessage* pMsg = syncNewVoteMsg(pRaft->selfGroupId, pRaft->selfId, 
-                                        nodeId, term, cType, lastIndex, lastTerm);
+                                        term, cType, lastIndex, lastTerm);
     if (pMsg == NULL) {
       continue;
     }

source/libs/sync/src/raft_handle_vote_message.c

@@ -15,6 +15,7 @@
 
 #include "syncInt.h"
 #include "raft.h"
+#include "raft_configuration.h"
 #include "raft_log.h"
 #include "raft_message.h"
 
@@ -31,12 +32,12 @@ int syncRaftHandleVoteMessage(SSyncRaft* pRaft, const SSyncMessage* pMsg) {
   SyncTerm lastTerm = syncRaftLogLastTerm(pRaft->log);
 
   grant = canGrantVoteMessage(pRaft, pMsg);
-  pRespMsg = syncNewVoteRespMsg(pRaft->selfGroupId, pRaft->selfId, pMsg->to, pMsg->vote.cType, !grant);
+  pRespMsg = syncNewVoteRespMsg(pRaft->selfGroupId, pRaft->selfId, pMsg->vote.cType, !grant);
   if (pRespMsg == NULL) {
     return 0;
   }
   syncInfo("[%d:%d] [logterm: %" PRId64 ", index: %" PRId64 ", vote: %d] %s for %d" \    
-    "[logterm: %" PRId64 ", index: %" PRId64 ", vote: %d] at term %" PRId64 "",
+    "[logterm: %" PRId64 ", index: %" PRId64 "] at term %" PRId64 "",
     pRaft->selfGroupId, pRaft->selfId, lastTerm, lastIndex, pRaft->voteFor,
     grant ? "grant" : "reject",
     pMsg->from, pMsg->vote.lastTerm, pMsg->vote.lastIndex, pRaft->term);
@@ -49,7 +50,7 @@ static bool canGrantVoteMessage(SSyncRaft* pRaft, const SSyncMessage* pMsg) {
   if (!(pRaft->voteFor == SYNC_NON_NODE_ID || pMsg->term > pRaft->term || pRaft->voteFor == pMsg->from)) {
     return false;
   }
-  if (!syncRaftLogIsUptodate(pRaft, pMsg->vote.lastIndex, pMsg->vote.lastTerm)) {
+  if (!syncRaftLogIsUptodate(pRaft->log, pMsg->vote.lastIndex, pMsg->vote.lastTerm)) {
     return false;
   }
 

source/libs/sync/src/raft_handle_vote_resp_message.c

@@ -15,6 +15,7 @@
 
 #include "syncInt.h"
 #include "raft.h"
+#include "raft_configuration.h"
 #include "raft_message.h"
 
 int syncRaftHandleVoteRespMessage(SSyncRaft* pRaft, const SSyncMessage* pMsg) {
@@ -45,8 +46,7 @@ int syncRaftHandleVoteRespMessage(SSyncRaft* pRaft, const SSyncMessage* pMsg) {
     if (pMsg->voteResp.cType == SYNC_RAFT_CAMPAIGN_PRE_ELECTION) {
       syncRaftStartElection(pRaft, SYNC_RAFT_CAMPAIGN_ELECTION);
     } else {
-      syncRaftBecomeLeader(pRaft);
-      syncRaftTriggerReplicate(pRaft);
+      syncRaftBecomeLeader(pRaft);      
     }
 
     return 0;

source/libs/sync/src/raft_log.c

@@ -37,4 +37,13 @@ int syncRaftLogNumOfPendingConf(SSyncRaftLog* pLog) {
 
 bool syncRaftHasUnappliedLog(SSyncRaftLog* pLog) {
   return pLog->commitIndex > pLog->appliedIndex;
+}
+
+SyncTerm syncRaftLogTermOf(SSyncRaftLog* pLog, SyncIndex index) {
+  return SYNC_NON_TERM;
+}
+
+int syncRaftLogAcquire(SSyncRaftLog* pLog, SyncIndex index, int maxMsgSize,
+                      SSyncRaftEntry **ppEntries, int *n) {
+  return 0;
 }
\ No newline at end of file

source/libs/sync/src/raft_progress.c

@@ -22,7 +22,6 @@
 static void resetProgressState(SSyncRaftProgress* progress, RaftProgressState state);
 
 static void resumeProgress(SSyncRaftProgress* progress);
-static void pauseProgress(SSyncRaftProgress* progress);
 
 int syncRaftProgressCreate(SSyncRaft* pRaft) {
 
@@ -58,11 +57,6 @@ bool syncRaftProgressMaybeUpdate(SSyncRaft* pRaft, int i, SyncIndex lastIndex) {
   return updated;
 }
 
-void syncRaftProgressOptimisticNextIndex(SSyncRaft* pRaft, int i, SyncIndex nextIndex) {
-  assert(i >= 0 && i < pRaft->leaderState.nProgress);
-  pRaft->leaderState.progress[i].nextIndex = nextIndex + 1;
-}
-
 bool syncRaftProgressMaybeDecrTo(SSyncRaft* pRaft, int i,
                                 SyncIndex rejected, SyncIndex lastIndex) {
   assert(i >= 0 && i < pRaft->leaderState.nProgress);
@@ -103,15 +97,7 @@ static void resumeProgress(SSyncRaftProgress* progress) {
   progress->paused = false;
 }
 
-static void pauseProgress(SSyncRaftProgress* progress) {
-  progress->paused = true;
-}
-
-bool syncRaftProgressIsPaused(SSyncRaft* pRaft, int i) {
-  assert(i >= 0 && i < pRaft->leaderState.nProgress);
-
-  SSyncRaftProgress* progress = &(pRaft->leaderState.progress[i]);
-
+bool syncRaftProgressIsPaused(SSyncRaftProgress* progress) {
   switch (progress->state) {
     case PROGRESS_PROBE:
       return progress->paused;

source/libs/sync/src/raft_replication.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/>.
+ */
+
+#include "raft.h"
+#include "raft_log.h"
+#include "raft_progress.h"
+#include "raft_replication.h"
+
+static int sendSnapshot(SSyncRaft* pRaft, int i);
+static int sendAppendEntries(SSyncRaft* pRaft, int i, SyncIndex index, SyncTerm term);
+
+int syncRaftReplicate(SSyncRaft* pRaft, int i) {
+  assert(pRaft->state == TAOS_SYNC_ROLE_LEADER);
+  assert(i >= 0 && i < pRaft->leaderState.nProgress);
+
+  SyncNodeId nodeId = pRaft->cluster.nodeInfo[i].nodeId;
+  SSyncRaftProgress* progress = &(pRaft->leaderState.progress[i]);
+  if (syncRaftProgressIsPaused(progress)) {
+    syncInfo("node %d paused", nodeId);
+    return 0;
+  }
+
+  SyncIndex nextIndex = syncRaftProgressNextIndex(progress);
+  SyncIndex prevIndex = nextIndex - 1;
+  SyncTerm prevTerm = syncRaftLogTermOf(pRaft->log, prevIndex);
+
+  if (prevTerm == SYNC_NON_TERM && !syncRaftProgressInSnapshot(progress)) {
+    goto send_snapshot;
+  }
+
+send_snapshot:
+  if (syncRaftProgressRecentActive(progress)) {
+    /* Only send a snapshot when we have heard from the server */
+    return sendSnapshot(pRaft, i);
+  } else {
+    /* Send empty AppendEntries RPC when we haven't heard from the server */
+    prevIndex = syncRaftLogLastIndex(pRaft->log);
+    prevTerm  = syncRaftLogLastTerm(pRaft->log);
+    return sendAppendEntries(pRaft, i, prevIndex, prevTerm);
+  }
+}
+
+static int sendSnapshot(SSyncRaft* pRaft, int i) {
+  return 0;
+}
+
+static int sendAppendEntries(SSyncRaft* pRaft, int i, SyncIndex prevIndex, SyncTerm prevTerm) {
+  SyncIndex nextIndex = prevIndex + 1;
+  SSyncRaftEntry *entries;
+  int nEntry;
+  SNodeInfo* pNode = &(pRaft->cluster.nodeInfo[i]);
+  SSyncRaftProgress* progress = &(pRaft->leaderState.progress[i]);
+  syncRaftLogAcquire(pRaft->log, nextIndex, pRaft->maxMsgSize, &entries, &nEntry);
+
+  SSyncMessage* msg = syncNewAppendMsg(pRaft->selfGroupId, pRaft->selfId, pRaft->term,
+                                      prevIndex, prevTerm, pRaft->log->commitIndex,
+                                      nEntry, entries);
+
+  if (msg == NULL) {
+    return 0;
+  }
+
+  pRaft->io.send(msg, pNode);
+
+  if (syncRaftProgressInReplicate(progress)) {
+    SyncIndex lastIndex = nextIndex + nEntry;
+    syncRaftProgressOptimisticNextIndex(progress, lastIndex);
+    syncRaftInflightAdd(&progress->inflights, lastIndex);
+  } else if (syncRaftProgressInProbe(progress)) {
+    syncRaftProgressPause(progress);
+  } else {
+
+  }
+
+  syncRaftProgressUpdateSendTick(progress, pRaft->currentTick);
+
+  return 0;
+}
\ No newline at end of file