[feeature][raft]add raft interface

include/libs/raft/raft_sync.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 TDENGINE_RAFT_SYNC_H
+#define TDENGINE_RAFT_SYNC_H
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include <stdint.h>
+#include "taosdef.h"
+#include "wal.h"
+
+typedef uint32_t SyncNodeId;
+typedef int64_t   SyncVersion;
+typedef uint64_t SSyncTerm;
+
+typedef enum {
+  TAOS_SYNC_ROLE_FOLLOWER  = 0,
+  TAOS_SYNC_ROLE_CANDIDATE = 1,
+  TAOS_SYNC_ROLE_LEADER  = 2,
+} ESyncRole;
+
+typedef struct {
+  void* data;
+  size_t len;
+} SSyncBuffer;
+
+typedef struct {
+  SyncNodeId  nodeId;    // node ID assigned by TDengine
+  uint16_t  nodePort;  // node sync Port
+  char      nodeFqdn[TSDB_FQDN_LEN]; // node FQDN  
+} SNodeInfo;
+
+typedef struct {
+  int selfIndex;
+  int nNode;
+  SNodeInfo*  nodeInfo;
+} SSyncCluster;
+
+typedef struct {
+  int32_t  selfIndex;
+  int nNode;
+  SyncNodeId* nodeId;
+  ESyncRole*  role;
+} SNodesRole;
+
+struct SSyncFSM;
+typedef struct SSyncFSM {
+  void* pData;
+
+  // apply committed log, bufs will be free by raft module
+  int (*applyLog)(struct SSyncFSM *fsm, SyncVersion index, const SSyncBuffer *buf, void *pData);
+
+  // cluster commit callback 
+  int (*onClusterChanged)(struct SSyncFSM *fsm, const SSyncCluster* cluster, void *pData);
+
+  // fsm return snapshot in ppBuf, bufs will be free by raft module
+  // TODO: getSnapshot SHOULD be async?
+  int (*getSnapshot)(struct SSyncFSM *fsm, SSyncBuffer **ppBuf, int* objId, bool *isLast);
+
+  // fsm apply snapshot with pBuf data
+  int (*applySnapshot)(struct SSyncFSM *fsm, SSyncBuffer *pBuf, int objId, bool isLast);
+
+  // call when restore snapshot and log done
+  int (*onRestoreDone)(struct SSyncFSM *fsm);
+
+  void (*onRollback)(struct SSyncFSM *fsm, SyncVersion index, const SSyncBuffer *buf);
+
+  void (*onRoleChanged)(struct SSyncFSM *fsm, const SNodesRole* pRole);
+
+} SSyncFSM;
+
+typedef struct SSyncServerState {
+  SyncNodeId voteFor;
+  SSyncTerm term;  
+} SSyncServerState;
+
+typedef struct SStateManager {
+  void* pData;
+
+  void (*saveServerState)(struct SStateManager* stateMng, const SSyncServerState* state);
+
+  const SSyncServerState* (*readServerState)(struct SStateManager* stateMng);
+
+  void (*saveCluster)(struct SStateManager* stateMng, const SSyncCluster* cluster);
+
+  const SSyncCluster* (*readCluster)(struct SStateManager* stateMng);
+} SStateManager;
+
+typedef struct {
+  int32_t  vgId;       // vgroup ID
+
+  twalh walHandle;
+
+  SyncVersion snapIndex;    // initial version
+  SSyncCluster syncCfg;    // configuration from mgmt
+
+  SSyncFSM fsm;
+
+  SStateManager stateManager;
+} SSyncInfo;
+
+int32_t syncInit();
+void    syncCleanUp();
+
+SyncNodeId syncStart(const SSyncInfo *);
+void    syncStop(SyncNodeId);
+
+int32_t syncPropose(SyncNodeId nodeId, SSyncBuffer buffer, void *pData, bool isWeak);
+
+extern int32_t  raftDebugFlag;
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif  // TDENGINE_RAFT_SYNC_H

source/libs/raft/CMakeLists.txt

 aux_source_directory(src RAFT_SRC)
 add_library(raft ${RAFT_SRC})
+
+target_link_libraries(
+    raft
+    PUBLIC common
+    PUBLIC util
+    PUBLIC wal
+)
+
 target_include_directories(
     raft
     PUBLIC "${CMAKE_SOURCE_DIR}/include/libs/raft"

source/libs/raft/src/raft.c

@@ -11,4 +11,6 @@
  *
  * 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/>.
- */
\ No newline at end of file
+ */
+
+#include "raft_sync.h"
\ No newline at end of file