refactor(sync): do leader transfer

source/libs/sync/src/syncMain.c

@@ -273,16 +273,8 @@ int32_t syncLeaderTransfer(int64_t rid) {
   }
   ASSERT(rid == pSyncNode->rid);
 
-  if (pSyncNode->peersNum == 0) {
-    taosReleaseRef(tsNodeRefId, pSyncNode->rid);
-    terrno = TSDB_CODE_SYN_INTERNAL_ERROR;
-    return -1;
-  }
-
-  SNodeInfo newLeader = (pSyncNode->peersNodeInfo)[0];
+  int32_t ret = syncNodeLeaderTransfer(pSyncNode);
   taosReleaseRef(tsNodeRefId, pSyncNode->rid);
-
-  int32_t ret = syncLeaderTransferTo(rid, newLeader);
   return ret;
 }
 
@@ -293,25 +285,8 @@ int32_t syncLeaderTransferTo(int64_t rid, SNodeInfo newLeader) {
     return -1;
   }
   ASSERT(rid == pSyncNode->rid);
-  int32_t ret = 0;
-
-  if (pSyncNode->replicaNum == 1) {
-    sError("only one replica, cannot drop leader");
-    taosReleaseRef(tsNodeRefId, pSyncNode->rid);
-    terrno = TSDB_CODE_SYN_ONE_REPLICA;
-    return -1;
-  }
 
-  SyncLeaderTransfer* pMsg = syncLeaderTransferBuild(pSyncNode->vgId);
-  pMsg->newLeaderId.addr = syncUtilAddr2U64(newLeader.nodeFqdn, newLeader.nodePort);
-  pMsg->newLeaderId.vgId = pSyncNode->vgId;
-  pMsg->newNodeInfo = newLeader;
-  ASSERT(pMsg != NULL);
-  SRpcMsg rpcMsg = {0};
-  syncLeaderTransfer2RpcMsg(pMsg, &rpcMsg);
-  syncLeaderTransferDestroy(pMsg);
-
-  ret = syncNodePropose(pSyncNode, &rpcMsg, false);
+  int32_t ret = syncNodeLeaderTransferTo(pSyncNode, newLeader);
   taosReleaseRef(tsNodeRefId, pSyncNode->rid);
   return ret;
 }
@@ -337,6 +312,12 @@ int32_t syncNodeLeaderTransferTo(SSyncNode* pSyncNode, SNodeInfo newLeader) {
     return -1;
   }
 
+  do {
+    char logBuf[128];
+    snprintf(logBuf, sizeof(logBuf), "begin leader transfer to %s:%u", newLeader.nodeFqdn, newLeader.nodePort);
+    syncNodeEventLog(pSyncNode, logBuf);
+  } while (0);
+
   SyncLeaderTransfer* pMsg = syncLeaderTransferBuild(pSyncNode->vgId);
   pMsg->newLeaderId.addr = syncUtilAddr2U64(newLeader.nodeFqdn, newLeader.nodePort);
   pMsg->newLeaderId.vgId = pSyncNode->vgId;
@@ -1147,8 +1128,6 @@ void syncNodeStartStandBy(SSyncNode* pSyncNode) {
 void syncNodeClose(SSyncNode* pSyncNode) {
   syncNodeEventLog(pSyncNode, "sync close");
 
-  // leader transfer
-
   int32_t ret;
   ASSERT(pSyncNode != NULL);
 
@@ -2643,7 +2622,7 @@ const char* syncStr(ESyncState state) {
 static int32_t syncDoLeaderTransfer(SSyncNode* ths, SRpcMsg* pRpcMsg, SSyncRaftEntry* pEntry) {
   SyncLeaderTransfer* pSyncLeaderTransfer = syncLeaderTransferFromRpcMsg2(pRpcMsg);
 
-  syncNodeEventLog(ths, "begin leader transfer");
+  syncNodeEventLog(ths, "do leader transfer");
 
   bool sameId = syncUtilSameId(&(pSyncLeaderTransfer->newLeaderId), &(ths->myRaftId));
   bool sameNodeInfo = strcmp(pSyncLeaderTransfer->newNodeInfo.nodeFqdn, ths->myNodeInfo.nodeFqdn) == 0 &&