add rpc to query raft status

src/interface/raftex.thrift

@@ -7,6 +7,21 @@ namespace cpp nebula.raftex
 
 include "common.thrift"
 
+enum Role {
+    LEADER      = 1, // the leader
+    FOLLOWER    = 2; // following a leader
+    CANDIDATE   = 3; // Has sent AskForVote request
+    LEARNER     = 4; // It is the same with FOLLOWER,
+                     // except it does not participate in leader election
+}
+
+enum Status {
+    STARTING            = 0; // The part is starting, not ready for service
+    RUNNING             = 1; // The part is running
+    STOPPED             = 2; // The part has been stopped
+    WAITING_SNAPSHOT    = 3; // Waiting for the snapshot.
+}
+
 enum ErrorCode {
     SUCCEEDED = 0;
 
@@ -154,9 +169,26 @@ struct SendSnapshotResponse {
     1: ErrorCode    error_code;
 }
 
+struct GetStateRequest {
+    1: GraphSpaceID space;              // Graphspace ID
+    2: PartitionID  part;               // Partition ID
+}
+
+struct GetStateResponse {
+    1: ErrorCode    error_code;
+    2: Role         role;
+    3: TermID       term;
+    4: bool         is_leader;
+    5: LogID        committed_log_id;
+    6: LogID        last_log_id;
+    7: TermID       last_log_term;
+    8: Status       status;
+}
+
 service RaftexService {
     AskForVoteResponse askForVote(1: AskForVoteRequest req);
     AppendLogResponse appendLog(1: AppendLogRequest req);
     SendSnapshotResponse sendSnapshot(1: SendSnapshotRequest req);
     HeartbeatResponse heartbeat(1: HeartbeatRequest req) (thread = 'eb');
+    GetStateResponse getState(1: GetStateRequest req);
 }

src/kvstore/raftex/RaftPart.cpp

@@ -998,6 +998,18 @@ bool RaftPart::prepareElectionRequest(cpp2::AskForVoteRequest& req,
   return true;
 }
 
+void RaftPart::getState(cpp2::GetStateResponse& resp) {
+  std::lock_guard<std::mutex> g(raftLock_);
+  resp.set_term(term_);
+  resp.set_role(nebula::raftex::cpp2::Role(role_));
+  resp.set_is_leader(role_ == Role::LEADER);
+  resp.set_error_code(cpp2::ErrorCode::SUCCEEDED);
+  resp.set_committed_log_id(committedLogId_);
+  resp.set_last_log_id(lastLogId_);
+  resp.set_last_log_term(lastLogTerm_);
+  resp.set_status(nebula::raftex::cpp2::Status(status_));
+}
+
 typename RaftPart::Role RaftPart::processElectionResponses(
     const RaftPart::ElectionResponses& results,
     std::vector<std::shared_ptr<Host>> hosts,

src/kvstore/raftex/RaftPart.h

@@ -196,6 +196,8 @@ class RaftPart : public std::enable_shared_from_this<RaftPart> {
    * Methods to process incoming raft requests
    *
    ****************************************************/
+  void getState(cpp2::GetStateResponse& resp);
+
   // Process the incoming leader election request
   void processAskForVoteRequest(const cpp2::AskForVoteRequest& req, cpp2::AskForVoteResponse& resp);
 

src/kvstore/raftex/RaftexService.cpp

@@ -171,6 +171,16 @@ std::shared_ptr<RaftPart> RaftexService::findPart(GraphSpaceID spaceId, Partitio
   return it->second;
 }
 
+void RaftexService::getState(cpp2::GetStateResponse& resp, const cpp2::GetStateRequest& req) {
+  auto part = findPart(req.get_space(), req.get_part());
+  if (part != nullptr) {
+    part->getState(resp);
+  } else {
+    resp.set_term(-1);
+    resp.set_error_code(cpp2::ErrorCode::E_UNKNOWN_PART);
+  }
+}
+
 void RaftexService::askForVote(cpp2::AskForVoteResponse& resp, const cpp2::AskForVoteRequest& req) {
   auto part = findPart(req.get_space(), req.get_part());
   if (!part) {

src/kvstore/raftex/RaftexService.h

@@ -38,6 +38,8 @@ class RaftexService : public cpp2::RaftexServiceSvIf {
 
   void askForVote(cpp2::AskForVoteResponse& resp, const cpp2::AskForVoteRequest& req) override;
 
+  void getState(cpp2::GetStateResponse& resp, const cpp2::GetStateRequest& req) override;
+
   void appendLog(cpp2::AppendLogResponse& resp, const cpp2::AppendLogRequest& req) override;
 
   void sendSnapshot(cpp2::SendSnapshotResponse& resp,