Clear space (vesoft-inc#681)

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

## What problem(s) does this PR solve?
#### Issue(s) number: 
fix vesoft-inc#3679

#### Description:

## How do you solve it?
https://confluence.nebula-graph.io/pages/viewpage.action?pageId=40535032


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


## Checklist:
Tests:
- [x] Unit test(positive and negative cases)
- [x] 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.）
- [x] 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:
> Added a  clear space feature, which will clear space data and index data, but keep space schema and index schema.


Migrated from vesoft-inc#3989

Co-authored-by: haifei.zhao <32253291+zhaohaifei@users.noreply.github.com>

.linters/cpp/checkKeyword.py

@@ -75,6 +75,7 @@
     'KW_ADD',
     'KW_CREATE',
     'KW_DROP',
+    'KW_CLEAR',
     'KW_REMOVE',
     'KW_IF',
     'KW_NOT',
@@ -134,25 +135,28 @@ def get_unreserved_keyword(file_path):
         if flag == 1:
             if line.strip() == ';':
                 break
-            unreserved_key_words.append(re.sub('\\s+[:|]\\s+(\\w+)\\s+.*', '\\1', line).strip())
+            unreserved_key_words.append(
+                re.sub('\\s+[:|]\\s+(\\w+)\\s+.*', '\\1', line).strip())
             continue
 
     parser_file.close()
     return unreserved_key_words
 
 
 if __name__ == '__main__':
-    cmd = 'git diff --diff-filter=ACMRTUXB HEAD -p ' + SCANNER_FILE_PATH + '|grep "^+"|grep -v "^+++"|grep "KW_"'
+    cmd = 'git diff --diff-filter=ACMRTUXB HEAD -p ' + \
+        SCANNER_FILE_PATH + '|grep "^+"|grep -v "^+++"|grep "KW_"'
     content = os.popen(cmd)
-    keywords=[]
-    for line in  content.readlines():
-        keyword = re.sub('.*(KW_\\w+)\s*;.*','\\1',line.strip())
+    keywords = []
+    for line in content.readlines():
+        keyword = re.sub('.*(KW_\\w+)\s*;.*', '\\1', line.strip())
         keywords.append(keyword)
 
     if len(keywords) == 0:
         exit(0)
     unreserved_key_words = get_unreserved_keyword(PARSER_FILE_PATH)
-    new_key_words = [word for word in keywords if word not in reserved_key_words]
+    new_key_words = [
+        word for word in keywords if word not in reserved_key_words]
     if len(new_key_words) == 0:
         exit(0)
     result = [word for word in new_key_words if word not in unreserved_key_words]

src/clients/meta/MetaClient.cpp

@@ -1357,6 +1357,22 @@ folly::Future<StatusOr<bool>> MetaClient::dropSpace(std::string name, const bool
   return future;
 }
 
+folly::Future<StatusOr<bool>> MetaClient::clearSpace(std::string name, const bool ifExists) {
+  cpp2::ClearSpaceReq req;
+  req.space_name_ref() = std::move(name);
+  req.if_exists_ref() = ifExists;
+  folly::Promise<StatusOr<bool>> promise;
+  auto future = promise.getFuture();
+  getResponse(
+      std::move(req),
+      [](auto client, auto request) { return client->future_clearSpace(request); },
+      [](cpp2::ExecResp&& resp) -> bool {
+        return resp.get_code() == nebula::cpp2::ErrorCode::SUCCEEDED;
+      },
+      std::move(promise));
+  return future;
+}
+
 folly::Future<StatusOr<std::vector<cpp2::HostItem>>> MetaClient::listHosts(cpp2::ListHostType tp) {
   cpp2::ListHostsReq req;
   req.type_ref() = tp;

src/clients/meta/MetaClient.h

@@ -304,6 +304,9 @@ class MetaClient {
 
   folly::Future<StatusOr<bool>> dropSpace(std::string name, bool ifExists = false);
 
+  // clear space data, but keep the space schema.
+  folly::Future<StatusOr<bool>> clearSpace(std::string name, bool ifExists = false);
+
   folly::Future<StatusOr<std::vector<cpp2::HostItem>>> listHosts(
       cpp2::ListHostType type = cpp2::ListHostType::ALLOC);
 

src/common/plugin/fulltext/FTGraphAdapter.h

@@ -47,6 +47,9 @@ class FTGraphAdapter {
 
   virtual StatusOr<bool> dropIndex(const HttpClient& client, const std::string& index) const = 0;
 
+  // Clear the fulltext index data and keep the index schema.
+  virtual StatusOr<bool> clearIndex(const HttpClient& client, const std::string& index) const = 0;
+
   virtual StatusOr<bool> indexExists(const HttpClient& client, const std::string& index) const = 0;
 };
 }  // namespace plugin

src/common/plugin/fulltext/elasticsearch/ESGraphAdapter.cpp

@@ -196,6 +196,28 @@ std::string ESGraphAdapter::dropIndexCmd(const HttpClient& client,
   return os.str();
 }
 
+StatusOr<bool> ESGraphAdapter::clearIndex(const HttpClient& client,
+                                          const std::string& index) const {
+  // curl -H "Content-Type: application/json; charset=utf-8"
+  // -XPOST "http://127.0.0.1:9200/${index}/_delete_by_query?refresh&slices=5"
+  // -d '{"query": {"match_all":{}}}'
+  std::string cmd = clearIndexCmd(client, index);
+  auto ret = nebula::ProcessUtils::runCommand(cmd.c_str());
+  if (!ret.ok() || ret.value().empty()) {
+    LOG(ERROR) << "Http POST Failed: " << cmd;
+    return Status::Error("command failed : %s", cmd.c_str());
+  }
+  return clearCheck(ret.value());
+}
+
+std::string ESGraphAdapter::clearIndexCmd(const HttpClient& client,
+                                          const std::string& index) const noexcept {
+  std::stringstream os;
+  os << header() << XPOST << client.toString() << index << "/_delete_by_query?refresh&slices=5\""
+     << " -d '{\"query\": {\"match_all\":{}}}'";
+  return os.str();
+}
+
 StatusOr<bool> ESGraphAdapter::indexExists(const HttpClient& client,
                                            const std::string& index) const {
   // curl -H "Content-Type: application/json; charset=utf-8"
@@ -283,5 +305,24 @@ bool ESGraphAdapter::indexCheck(const std::string& ret) const {
   LOG(ERROR) << "error reason : " << ret;
   return false;
 }
+
+bool ESGraphAdapter::clearCheck(const std::string& ret) const {
+  try {
+    auto root = folly::parseJson(ret);
+    if (root.isArray()) {
+      return false;
+    }
+    auto result = root.find("failures");
+    if (result != root.items().end() && result->second.isArray() && result->second.size() == 0) {
+      return true;
+    }
+  } catch (const std::exception& ex) {
+    LOG(ERROR) << "result error : " << ex.what();
+  }
+
+  LOG(ERROR) << "error reason : " << ret;
+  return false;
+}
+
 }  // namespace plugin
 }  // namespace nebula

src/common/plugin/fulltext/elasticsearch/ESGraphAdapter.h

@@ -21,6 +21,7 @@ class ESGraphAdapter final : public FTGraphAdapter {
   FRIEND_TEST(FulltextPluginTest, ESFuzzyTest);
   FRIEND_TEST(FulltextPluginTest, ESCreateIndexTest);
   FRIEND_TEST(FulltextPluginTest, ESDropIndexTest);
+  FRIEND_TEST(FulltextPluginTest, ESClearIndexTest);
 
  public:
   static std::unique_ptr<FTGraphAdapter> kAdapter;
@@ -53,6 +54,11 @@ class ESGraphAdapter final : public FTGraphAdapter {
 
   StatusOr<bool> dropIndex(const HttpClient& client, const std::string& index) const override;
 
+  // Clear the fulltext index data on es and keep the index schema.
+  // client: es client
+  // index: fulltext index name
+  StatusOr<bool> clearIndex(const HttpClient& client, const std::string& index) const override;
+
   StatusOr<bool> indexExists(const HttpClient& client, const std::string& index) const override;
 
  private:
@@ -88,12 +94,20 @@ class ESGraphAdapter final : public FTGraphAdapter {
 
   bool indexCheck(const std::string& ret) const;
 
+  // check the result
+  bool clearCheck(const std::string& ret) const;
+
   std::string createIndexCmd(const HttpClient& client,
                              const std::string& index,
                              const std::string& indexTemplate = "") const noexcept;
 
   std::string dropIndexCmd(const HttpClient& client, const std::string& index) const noexcept;
 
+  // Encapsulates the clearIndex command.
+  // client: es client
+  // index: fulltext index name
+  std::string clearIndexCmd(const HttpClient& client, const std::string& index) const noexcept;
+
   std::string indexExistsCmd(const HttpClient& client, const std::string& index) const noexcept;
 };
 }  // namespace plugin

src/common/plugin/fulltext/test/FulltextPluginTest.cpp

@@ -64,6 +64,17 @@ TEST(FulltextPluginTest, ESDropIndexTest) {
   ASSERT_EQ(expected, ret);
 }
 
+TEST(FulltextPluginTest, ESClearIndexTest) {
+  HostAddr localHost_{"127.0.0.1", 9200};
+  HttpClient client(localHost_);
+  auto ret = ESGraphAdapter().clearIndexCmd(client, "test_index");
+  auto expected =
+      "/usr/bin/curl -H \"Content-Type: application/json; charset=utf-8\""
+      " -XPOST -k \"http://127.0.0.1:9200/test_index/_delete_by_query?refresh&slices=5\""
+      " -d '{\"query\": {\"match_all\":{}}}'";
+  ASSERT_EQ(expected, ret);
+}
+
 TEST(FulltextPluginTest, ESPutTest) {
   HostAddr localHost_{"127.0.0.1", 9200};
   HttpClient hc(localHost_);

src/graph/executor/Executor.cpp

@@ -271,6 +271,9 @@ Executor *Executor::makeExecutor(QueryContext *qctx, const PlanNode *node) {
     case PlanNode::Kind::kDropSpace: {
       return pool->add(new DropSpaceExecutor(node, qctx));
     }
+    case PlanNode::Kind::kClearSpace: {
+      return pool->add(new ClearSpaceExecutor(node, qctx));
+    }
     case PlanNode::Kind::kShowCreateSpace: {
       return pool->add(new ShowCreateSpaceExecutor(node, qctx));
     }

src/graph/executor/admin/SpaceExecutor.cpp

@@ -176,6 +176,50 @@ void DropSpaceExecutor::unRegisterSpaceLevelMetrics(const std::string &spaceName
   }
 }
 
+folly::Future<Status> ClearSpaceExecutor::execute() {
+  SCOPED_TIMER(&execTime_);
+
+  auto *csNode = asNode<ClearSpace>(node());
+
+  // prepare text search index.
+  std::vector<std::string> ftIndexes;
+  auto spaceIdRet = qctx()->getMetaClient()->getSpaceIdByNameFromCache(csNode->getSpaceName());
+  if (spaceIdRet.ok()) {
+    auto ftIndexesRet = qctx()->getMetaClient()->getFTIndexBySpaceFromCache(spaceIdRet.value());
+    NG_RETURN_IF_ERROR(ftIndexesRet);
+    auto map = std::move(ftIndexesRet).value();
+    auto get = [](const auto &ptr) { return ptr.first; };
+    std::transform(map.begin(), map.end(), std::back_inserter(ftIndexes), get);
+  } else {
+    LOG(WARNING) << "Get space ID failed when prepare text index: " << csNode->getSpaceName();
+  }
+
+  return qctx()
+      ->getMetaClient()
+      ->clearSpace(csNode->getSpaceName(), csNode->getIfExists())
+      .via(runner())
+      .thenValue([this, csNode, spaceIdRet, ftIndexes = std::move(ftIndexes)](StatusOr<bool> resp) {
+        if (!resp.ok()) {
+          LOG(ERROR) << "Clear space `" << csNode->getSpaceName() << "' failed: " << resp.status();
+          return resp.status();
+        }
+        if (!ftIndexes.empty()) {
+          auto tsRet = FTIndexUtils::getTSClients(qctx()->getMetaClient());
+          if (!tsRet.ok()) {
+            LOG(WARNING) << "Get text search clients failed";
+            return Status::OK();
+          }
+          for (const auto &ftindex : ftIndexes) {
+            auto ftRet = FTIndexUtils::clearTSIndex(std::move(tsRet).value(), ftindex);
+            if (!ftRet.ok()) {
+              LOG(WARNING) << "Clear fulltext index `" << ftindex << "' failed: " << ftRet.status();
+            }
+          }
+        }
+        return Status::OK();
+      });
+}
+
 folly::Future<Status> ShowSpacesExecutor::execute() {
   SCOPED_TIMER(&execTime_);
 

src/graph/executor/admin/SpaceExecutor.h

@@ -45,6 +45,14 @@ class DropSpaceExecutor final : public Executor {
   folly::Future<Status> execute() override;
 };
 
+class ClearSpaceExecutor final : public Executor {
+ public:
+  ClearSpaceExecutor(const PlanNode *node, QueryContext *qctx)
+      : Executor("ClearSpaceExecutor", node, qctx) {}
+
+  folly::Future<Status> execute() override;
+};
+
 class ShowSpacesExecutor final : public Executor {
  public:
   ShowSpacesExecutor(const PlanNode *node, QueryContext *qctx)

src/graph/planner/plan/Admin.cpp

@@ -34,6 +34,13 @@ std::unique_ptr<PlanNodeDescription> DropSpace::explain() const {
   return desc;
 }
 
+std::unique_ptr<PlanNodeDescription> ClearSpace::explain() const {
+  auto desc = SingleDependencyNode::explain();
+  addDescription("spaceName", spaceName_, desc.get());
+  addDescription("ifExists", util::toJson(ifExists_), desc.get());
+  return desc;
+}
+
 std::unique_ptr<PlanNodeDescription> DescSpace::explain() const {
   auto desc = SingleDependencyNode::explain();
   addDescription("spaceName", spaceName_, desc.get());

src/graph/planner/plan/Admin.h

@@ -218,6 +218,37 @@ class DropSpace final : public SingleDependencyNode {
   bool ifExists_;
 };
 
+class ClearSpace final : public SingleDependencyNode {
+ public:
+  static ClearSpace* make(QueryContext* qctx,
+                          PlanNode* input,
+                          std::string spaceName,
+                          bool ifExists) {
+    return qctx->objPool()->add(new ClearSpace(qctx, input, std::move(spaceName), ifExists));
+  }
+
+  std::unique_ptr<PlanNodeDescription> explain() const override;
+
+  const std::string& getSpaceName() const {
+    return spaceName_;
+  }
+
+  bool getIfExists() const {
+    return ifExists_;
+  }
+
+ private:
+  ClearSpace(QueryContext* qctx, PlanNode* input, std::string spaceName, bool ifExists)
+      : SingleDependencyNode(qctx, Kind::kClearSpace, input) {
+    spaceName_ = std::move(spaceName);
+    ifExists_ = ifExists;
+  }
+
+ private:
+  std::string spaceName_;
+  bool ifExists_;
+};
+
 class AlterSpace final : public SingleDependencyNode {
  public:
   static AlterSpace* make(QueryContext* qctx,

src/graph/planner/plan/PlanNode.cpp

@@ -169,6 +169,8 @@ const char* PlanNode::toString(PlanNode::Kind kind) {
       return "ShowCreateEdgeIndex";
     case Kind::kDropSpace:
       return "DropSpace";
+    case Kind::kClearSpace:
+      return "ClearSpace";
     case Kind::kDropTag:
       return "DropTag";
     case Kind::kDropEdge:

src/graph/planner/plan/PlanNode.h

@@ -96,6 +96,7 @@ class PlanNode {
     kShowCreateTag,
     kShowCreateEdge,
     kDropSpace,
+    kClearSpace,
     kDropTag,
     kDropEdge,
     kAlterSpace,

src/graph/service/PermissionCheck.cpp

@@ -10,8 +10,8 @@ namespace graph {
 
 /**
  * Read space : kUse, kDescribeSpace
- * Write space : kCreateSpace, kDropSpace, kCreateSnapshot, kDropSnapshot
- *               kBalance, kAdmin, kConfig, kIngest, kDownload
+ * Write space : kCreateSpace, kDropSpace, kClearSpace, kCreateSnapshot,
+ *               kDropSnapshot, kBalance, kAdmin, kConfig, kIngest, kDownload
  * Read schema : kDescribeTag, kDescribeEdge,
  *               kDescribeTagIndex, kDescribeEdgeIndex
  * Write schema : kCreateTag, kAlterTag, kCreateEdge,
@@ -53,6 +53,7 @@ namespace graph {
     case Sentence::Kind::kAlterSpace:
     case Sentence::Kind::kCreateSpaceAs:
     case Sentence::Kind::kDropSpace:
+    case Sentence::Kind::kClearSpace:
     case Sentence::Kind::kCreateSnapshot:
     case Sentence::Kind::kDropSnapshot:
     case Sentence::Kind::kAddHosts:

src/graph/util/FTIndexUtils.cpp

@@ -76,6 +76,20 @@ StatusOr<bool> FTIndexUtils::dropTSIndex(const std::vector<nebula::plugin::HttpC
   return Status::Error("drop fulltext index failed : %s", index.c_str());
 }
 
+StatusOr<bool> FTIndexUtils::clearTSIndex(const std::vector<nebula::plugin::HttpClient>& tsClients,
+                                          const std::string& index) {
+  auto retryCnt = FLAGS_ft_request_retry_times;
+  while (--retryCnt > 0) {
+    auto ret =
+        nebula::plugin::ESGraphAdapter::kAdapter->clearIndex(randomFTClient(tsClients), index);
+    if (!ret.ok()) {
+      continue;
+    }
+    return std::move(ret).value();
+  }
+  return Status::Error("clear fulltext index failed : %s", index.c_str());
+}
+
 StatusOr<Expression*> FTIndexUtils::rewriteTSFilter(
     ObjectPool* pool,
     bool isEdge,

src/graph/util/FTIndexUtils.h

@@ -28,6 +28,10 @@ class FTIndexUtils final {
   static StatusOr<bool> dropTSIndex(const std::vector<nebula::plugin::HttpClient>& tsClients,
                                     const std::string& index);
 
+  // Clears the full-text index data, but keeps the index schema
+  static StatusOr<bool> clearTSIndex(const std::vector<nebula::plugin::HttpClient>& tsClients,
+                                     const std::string& index);
+
   // Converts TextSearchExpression into a relational expresion that could be pushed down
   static StatusOr<Expression*> rewriteTSFilter(
       ObjectPool* pool,