[KYUUBI #5797] Support to describe engine with command in current session

kyuubi-server/src/main/antlr4/org/apache/kyuubi/sql/KyuubiSqlBaseLexer.g4

@@ -51,6 +51,8 @@ KYUUBIADMIN: 'KYUUBIADMIN';
 
 SESSION: 'SESSION';
 
+ENGINE: 'ENGINE';
+
 BACKQUOTED_IDENTIFIER
     : '`' ( ~'`' | '``' )* '`'
     ;

kyuubi-server/src/main/antlr4/org/apache/kyuubi/sql/KyuubiSqlBaseParser.g4

@@ -30,4 +30,5 @@ statement
 
 runnableCommand
     : (DESC | DESCRIBE) SESSION                                     #describeSession
+    | (DESC | DESCRIBE) ENGINE                                      #describeEngine
     ;

kyuubi-server/src/main/scala/org/apache/kyuubi/sql/parser/server/KyuubiAstBuilder.scala

@@ -20,7 +20,7 @@ package org.apache.kyuubi.sql.parser.server
 import org.apache.kyuubi.sql.{KyuubiSqlBaseParser, KyuubiSqlBaseParserBaseVisitor}
 import org.apache.kyuubi.sql.KyuubiSqlBaseParser.SingleStatementContext
 import org.apache.kyuubi.sql.plan.{KyuubiTreeNode, PassThroughNode}
-import org.apache.kyuubi.sql.plan.command.{DescribeSession, RunnableCommand}
+import org.apache.kyuubi.sql.plan.command.{DescribeEngine, DescribeSession, RunnableCommand}
 
 class KyuubiAstBuilder extends KyuubiSqlBaseParserBaseVisitor[AnyRef] {
 
@@ -44,4 +44,9 @@ class KyuubiAstBuilder extends KyuubiSqlBaseParserBaseVisitor[AnyRef] {
       : RunnableCommand = {
     DescribeSession()
   }
+
+  override def visitDescribeEngine(ctx: KyuubiSqlBaseParser.DescribeEngineContext)
+      : RunnableCommand = {
+    DescribeEngine()
+  }
 }

kyuubi-server/src/main/scala/org/apache/kyuubi/sql/plan/command/DescribeEngine.scala

@@ -0,0 +1,64 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.kyuubi.sql.plan.command
+
+import scala.collection.mutable.ListBuffer
+
+import org.apache.kyuubi.operation.IterableFetchIterator
+import org.apache.kyuubi.session.{KyuubiSession, KyuubiSessionImpl}
+import org.apache.kyuubi.shaded.hive.service.rpc.thrift.TTypeId
+import org.apache.kyuubi.sql.schema.{Column, Row, Schema}
+
+/**
+ * A runnable node for description the current session engine.
+ *
+ * The syntax of using this command in SQL is:
+ * {{{
+ *   [DESC|DESCRIBE] ENGINE;
+ * }}}
+ */
+case class DescribeEngine() extends RunnableCommand {
+
+  override def run(kyuubiSession: KyuubiSession): Unit = {
+    val rows = Seq(kyuubiSession).map { session =>
+      lazy val client = session.asInstanceOf[KyuubiSessionImpl].client
+      val values = new ListBuffer[String]()
+      values += client.engineId.getOrElse("")
+      values += client.engineName.getOrElse("")
+      values += client.engineUrl.getOrElse("")
+      Row(values.toList)
+    }
+    iter = new IterableFetchIterator(rows)
+  }
+
+  override def resultSchema: Schema = {
+    Schema(DescribeEngine.outputCols().toList)
+  }
+
+  override def name(): String = "Describe Engine Node"
+}
+
+object DescribeEngine {
+
+  def outputCols(): Seq[Column] = {
+    Seq(
+      Column("ENGINE_ID", TTypeId.STRING_TYPE, Some("Kyuubi engine identify")),
+      Column("ENGINE_NAME", TTypeId.STRING_TYPE, Some("Kyuubi engine name")),
+      Column("ENGINE_URL", TTypeId.STRING_TYPE, Some("Kyuubi engine url")))
+  }
+}

kyuubi-server/src/main/scala/org/apache/kyuubi/sql/plan/command/DescribeSession.scala

@@ -56,8 +56,8 @@ object DescribeSession {
 
   def outputCols(): Seq[Column] = {
     Seq(
-      Column("id", TTypeId.STRING_TYPE, Some("Kyuubi session identify")),
-      Column("user", TTypeId.STRING_TYPE, Some("Kyuubi session user")),
-      Column("type", TTypeId.STRING_TYPE, Some("Kyuubi session type")))
+      Column("SESSION_ID", TTypeId.STRING_TYPE, Some("Kyuubi session identify")),
+      Column("SESSION_USER", TTypeId.STRING_TYPE, Some("Kyuubi session user")),
+      Column("SESSION_TYPE", TTypeId.STRING_TYPE, Some("Kyuubi session type")))
   }
 }

kyuubi-server/src/test/scala/org/apache/kyuubi/operation/parser/DescribeEngineSuite.scala

@@ -0,0 +1,35 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.kyuubi.operation.parser
+
+class DescribeEngineSuite extends ExecutedCommandExecSuite {
+
+  test("desc/describe kyuubi engine") {
+    Seq("DESC", "DESCRIBE").foreach { desc =>
+      withJdbcStatement() { statement =>
+        val resultSet = statement.executeQuery(s"KYUUBI $desc ENGINE")
+        assert(resultSet.next())
+
+        assert(resultSet.getMetaData.getColumnCount == 3)
+        assert(resultSet.getMetaData.getColumnName(1) == "ENGINE_ID")
+        assert(resultSet.getMetaData.getColumnName(2) == "ENGINE_NAME")
+        assert(resultSet.getMetaData.getColumnName(3) == "ENGINE_URL")
+      }
+    }
+  }
+}

kyuubi-server/src/test/scala/org/apache/kyuubi/operation/parser/DescribeSessionSuite.scala

@@ -19,15 +19,17 @@ package org.apache.kyuubi.operation.parser
 
 class DescribeSessionSuite extends ExecutedCommandExecSuite {
 
-  test("desc kyuubi session") {
-    withJdbcStatement() { statement =>
-      val resultSet = statement.executeQuery("KYUUBI DESC SESSION")
-      assert(resultSet.next())
+  test("desc/describe kyuubi session") {
+    Seq("DESC", "DESCRIBE").foreach { desc =>
+      withJdbcStatement() { statement =>
+        val resultSet = statement.executeQuery(s"KYUUBI $desc SESSION")
+        assert(resultSet.next())
 
-      assert(resultSet.getMetaData.getColumnCount == 3)
-      assert(resultSet.getMetaData.getColumnName(1) == "id")
-      assert(resultSet.getMetaData.getColumnName(2) == "user")
-      assert(resultSet.getMetaData.getColumnName(3) == "type")
+        assert(resultSet.getMetaData.getColumnCount == 3)
+        assert(resultSet.getMetaData.getColumnName(1) == "SESSION_ID")
+        assert(resultSet.getMetaData.getColumnName(2) == "SESSION_USER")
+        assert(resultSet.getMetaData.getColumnName(3) == "SESSION_TYPE")
+      }
     }
   }
 }

kyuubi-server/src/test/scala/org/apache/kyuubi/parser/KyuubiParserSuite.scala

@@ -20,7 +20,7 @@ package org.apache.kyuubi.parser
 import org.apache.kyuubi.KyuubiFunSuite
 import org.apache.kyuubi.sql.parser.server.KyuubiParser
 import org.apache.kyuubi.sql.plan.PassThroughNode
-import org.apache.kyuubi.sql.plan.command.DescribeSession
+import org.apache.kyuubi.sql.plan.command.{DescribeEngine, DescribeSession}
 
 class KyuubiParserSuite extends KyuubiFunSuite {
 
@@ -51,4 +51,11 @@ class KyuubiParserSuite extends KyuubiFunSuite {
     assert(node.isInstanceOf[DescribeSession])
     assert(node.name() == "Describe Session Node")
   }
+
+  test("Describe session engine") {
+    val node = parser.parsePlan("KYUUBI DESC ENGINE")
+
+    assert(node.isInstanceOf[DescribeEngine])
+    assert(node.name() == "Describe Engine Node")
+  }
 }