machine not registed should response leader address (vesoft-inc#666)

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## What type of PR is this?
- [ ] bug
- [ ] feature
- [x] enhancement

## What problem(s) does this PR solve?
#### Issue(s) number: 

#### Description:


## How do you solve it?



## Special notes for your reviewer, ex. impact of this fix, design document, etc:



## Checklist:
Tests:
- [ ] Unit test(positive and negative cases)
- [ ] Function test
- [ ] Performance test
- [ ] N/A

Affects:
- [x] Documentation affected (Please add the label if documentation needs to be modified.)
- [ ] Incompatibility (If it breaks the compatibility, please describe it and add the label.）
- [ ] If it's needed to cherry-pick (If cherry-pick to some branches is required, please label the destination version(s).)
- [ ] Performance impacted: Consumes more CPU/Memory


## Release notes:

Please confirm whether to be reflected in release notes and how to describe:
> ex. Fixed the bug .....
Fix faq, see
https://docs.nebula-graph.com.cn/3.0.0/20.appendix/0.FAQ/#nebula_graph_nebula-storaged 

Migrated from vesoft-inc#3950

Co-authored-by: yaphet <[email protected]>

src/clients/meta/MetaClient.cpp

@@ -834,11 +834,12 @@ void MetaClient::getResponse(Request req,
               }
 
               auto&& resp = t.value();
-              if (resp.get_code() == nebula::cpp2::ErrorCode::SUCCEEDED) {
+              auto code = resp.get_code();
+              if (code == nebula::cpp2::ErrorCode::SUCCEEDED) {
                 // succeeded
                 pro.setValue(respGen(std::move(resp)));
                 return;
-              } else if (resp.get_code() == nebula::cpp2::ErrorCode::E_LEADER_CHANGED) {
+              } else if (code == nebula::cpp2::ErrorCode::E_LEADER_CHANGED) {
                 updateLeader(resp.get_leader());
                 if (retry < retryLimit) {
                   evb->runAfterDelay(
@@ -861,7 +862,7 @@ void MetaClient::getResponse(Request req,
                       FLAGS_meta_client_retry_interval_secs * 1000);
                   return;
                 }
-              } else if (resp.get_code() == nebula::cpp2::ErrorCode::E_CLIENT_SERVER_INCOMPATIBLE) {
+              } else if (code == nebula::cpp2::ErrorCode::E_CLIENT_SERVER_INCOMPATIBLE) {
                 pro.setValue(respGen(std::move(resp)));
                 return;
               } else if (resp.get_code() == nebula::cpp2::ErrorCode::E_MACHINE_NOT_FOUND) {

src/meta/processors/BaseProcessor.h

@@ -67,26 +67,20 @@ class BaseProcessor {
    * @brief Set error code and handle leader changed.
    *
    * @param code
-   * @param spaceId
-   * @param partId
    */
-  void handleErrorCode(nebula::cpp2::ErrorCode code,
-                       GraphSpaceID spaceId = kDefaultSpaceId,
-                       PartitionID partId = kDefaultPartId) {
+  void handleErrorCode(nebula::cpp2::ErrorCode code) {
     resp_.code_ref() = code;
     if (code == nebula::cpp2::ErrorCode::E_LEADER_CHANGED) {
-      handleLeaderChanged(spaceId, partId);
+      handleLeaderChanged();
     }
   }
 
   /**
    * @brief Set leader address to reponse.
    *
-   * @param spaceId
-   * @param partId
    */
-  void handleLeaderChanged(GraphSpaceID spaceId, PartitionID partId) {
-    auto leaderRet = kvstore_->partLeader(spaceId, partId);
+  void handleLeaderChanged() {
+    auto leaderRet = kvstore_->partLeader(kDefaultSpaceId, kDefaultPartId);
     if (ok(leaderRet)) {
       resp_.leader_ref() = toThriftHost(nebula::value(leaderRet));
     } else {

src/meta/processors/admin/HBProcessor.cpp

@@ -52,6 +52,7 @@ void HBProcessor::process(const cpp2::HBReq& req) {
       if (!ActiveHostsMan::machineRegisted(kvstore_, host)) {
         LOG(INFO) << "Machine " << host << " is not registed";
         handleErrorCode(nebula::cpp2::ErrorCode::E_MACHINE_NOT_FOUND);
+        setLeaderInfo();
         onFinished();
         return;
       }
@@ -173,5 +174,14 @@ nebula::cpp2::ErrorCode HBProcessor::checkNodeNumber(const cpp2::HostRole role,
   return nebula::cpp2::ErrorCode::SUCCEEDED;
 }
 
+void HBProcessor::setLeaderInfo() {
+  auto leaderRet = kvstore_->partLeader(kDefaultSpaceId, kDefaultPartId);
+  if (ok(leaderRet)) {
+    resp_.leader_ref() = toThriftHost(nebula::value(leaderRet));
+  } else {
+    resp_.code_ref() = nebula::error(leaderRet);
+  }
+}
+
 }  // namespace meta
 }  // namespace nebula

src/meta/processors/admin/HBProcessor.h

@@ -60,6 +60,8 @@ class HBProcessor : public BaseProcessor<cpp2::HBResp> {
 
   nebula::cpp2::ErrorCode checkNodeNumber(const cpp2::HostRole role, const HostAddr& host);
 
+  void setLeaderInfo();
+
   ClusterID clusterId_{0};
   const HBCounters* counters_{nullptr};
   static std::atomic<int64_t> metaVersion_;