refactor(sync): pre snapshot on message

include/libs/sync/syncTools.h

@@ -550,7 +550,7 @@ typedef struct SyncPreSnapshotReply {
 
   // private data
   SyncTerm  term;
-  SyncIndex matchIndex;
+  SyncIndex snapStart;
 
 } SyncPreSnapshotReply;
 

source/libs/sync/src/syncMain.c

@@ -3702,8 +3702,9 @@ void syncLogSendSyncPreSnapshotReply(SSyncNode* pSyncNode, const SyncPreSnapshot
   uint16_t port;
   syncUtilU642Addr(pMsg->destId.addr, host, sizeof(host), &port);
   char logBuf[256];
-  snprintf(logBuf, sizeof(logBuf), "send sync-pre-snapshot-reply to %s:%d {term:%" PRIu64 ", match:%" PRId64 "}, %s",
-           host, port, pMsg->term, pMsg->matchIndex, s);
+  snprintf(logBuf, sizeof(logBuf),
+           "send sync-pre-snapshot-reply to %s:%d {term:%" PRIu64 ", snap-start:%" PRId64 "}, %s", host, port,
+           pMsg->term, pMsg->snapStart, s);
   syncNodeEventLog(pSyncNode, logBuf);
 }
 
@@ -3712,7 +3713,8 @@ void syncLogRecvSyncPreSnapshotReply(SSyncNode* pSyncNode, const SyncPreSnapshot
   uint16_t port;
   syncUtilU642Addr(pMsg->srcId.addr, host, sizeof(host), &port);
   char logBuf[256];
-  snprintf(logBuf, sizeof(logBuf), "recv sync-pre-snapshot-reply from %s:%d {term:%" PRIu64 ", match:%" PRId64 "}, %s",
-           host, port, pMsg->term, pMsg->matchIndex, s);
+  snprintf(logBuf, sizeof(logBuf),
+           "recv sync-pre-snapshot-reply from %s:%d {term:%" PRIu64 ", snap-start:%" PRId64 "}, %s", host, port,
+           pMsg->term, pMsg->snapStart, s);
   syncNodeEventLog(pSyncNode, logBuf);
 }

source/libs/sync/src/syncMessage.c

@@ -2568,8 +2568,8 @@ cJSON* syncPreSnapshotReply2Json(const SyncPreSnapshotReply* pMsg) {
     snprintf(u64buf, sizeof(u64buf), "%" PRIu64, pMsg->term);
     cJSON_AddStringToObject(pRoot, "term", u64buf);
 
-    snprintf(u64buf, sizeof(u64buf), "%" PRId64, pMsg->matchIndex);
-    cJSON_AddStringToObject(pRoot, "match-index", u64buf);
+    snprintf(u64buf, sizeof(u64buf), "%" PRId64, pMsg->snapStart);
+    cJSON_AddStringToObject(pRoot, "snap-start", u64buf);
   }
 
   cJSON* pJson = cJSON_CreateObject();

source/libs/sync/src/syncSnapshot.c

@@ -925,10 +925,60 @@ int32_t syncNodeOnSnapshotReply(SSyncNode *pSyncNode, SyncSnapshotRsp *pMsg) {
 
 int32_t syncNodeOnPreSnapshot(SSyncNode *ths, SyncPreSnapshot *pMsg) {
   syncLogRecvSyncPreSnapshot(ths, pMsg, "");
+
+  SyncPreSnapshotReply *pMsgReply = syncPreSnapshotReplyBuild(ths->vgId);
+  pMsgReply->srcId = ths->myRaftId;
+  pMsgReply->destId = pMsg->srcId;
+  pMsgReply->term = ths->pRaftStore->currentTerm;
+
+  SSyncLogStoreData *pData = ths->pLogStore->data;
+  SWal              *pWal = pData->pWal;
+
+  if (syncNodeIsMnode(ths)) {
+    pMsgReply->snapStart = SYNC_INDEX_BEGIN;
+
+  } else {
+    bool    isEmpty = ths->pLogStore->syncLogIsEmpty(ths->pLogStore);
+    int64_t walCommitVer = walGetCommittedVer(pWal);
+
+    if (!isEmpty && ths->commitIndex != walCommitVer) {
+      char logBuf[128];
+      snprintf(logBuf, sizeof(logBuf), "commit not same, wal-commit:%" PRId64 ", commit:%" PRId64 ", ignore",
+               walCommitVer, ths->commitIndex);
+      syncNodeErrorLog(ths, logBuf);
+
+      goto _IGNORE;
+    }
+
+    pMsgReply->snapStart = ths->commitIndex + 1;
+
+    // make local log clean
+    int32_t code = ths->pLogStore->syncLogTruncate(ths->pLogStore, pMsgReply->snapStart);
+    if (code != 0) {
+      syncNodeErrorLog(ths, "truncate wal error");
+      goto _IGNORE;
+    }
+  }
+
+  // can not write behind _RESPONSE
+  SRpcMsg rpcMsg;
+
+_RESPONSE:
+  syncPreSnapshotReply2RpcMsg(pMsgReply, &rpcMsg);
+  syncNodeSendMsgById(&pMsgReply->destId, ths, &rpcMsg);
+
+  syncPreSnapshotReplyDestroy(pMsgReply);
+  return 0;
+
+_IGNORE:
+  syncPreSnapshotReplyDestroy(pMsgReply);
   return 0;
 }
 
 int32_t syncNodeOnPreSnapshotReply(SSyncNode *ths, SyncPreSnapshotReply *pMsg) {
   syncLogRecvSyncPreSnapshotReply(ths, pMsg, "");
+
+  // start snapshot
+
   return 0;
 }
\ No newline at end of file

source/libs/sync/test/syncPreSnapshotReplyTest.cpp

@@ -22,7 +22,7 @@ SyncPreSnapshotReply *createMsg() {
   pMsg->destId.addr = syncUtilAddr2U64("127.0.0.1", 5678);
   pMsg->destId.vgId = 100;
   pMsg->term = 9527;
-  pMsg->matchIndex = 12306;
+  pMsg->snapStart = 12306;
   return pMsg;
 }