submarine-security/spark-security/src/main/scala/org/apache/spark/sql/execution/SubmarineShowDatabasesCommand.scala

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 * 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
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package org.apache.spark.sql.execution

import org.apache.spark.sql.{Row, SparkSession}
import org.apache.spark.sql.execution.command.RunnableCommand

import org.apache.submarine.spark.compatible.CompatibleCommand.ShowDatabasesCommandCompatible
import org.apache.submarine.spark.compatible.CompatibleFunc
import org.apache.submarine.spark.security.{RangerSparkAuthorizer, SparkPrivilegeObject, SparkPrivilegeObjectType}

case class SubmarineShowDatabasesCommand(child: ShowDatabasesCommandCompatible)
  extends RunnableCommand {
  override val output = child.output

  override def run(sparkSession: SparkSession): Seq[Row] = {
    val catalog = sparkSession.sessionState.catalog
    val databases = CompatibleFunc.getPattern(child)
      .map(catalog.listDatabases).getOrElse(catalog.listDatabases()).map { d => Row(d) }

    databases.filter(r => RangerSparkAuthorizer.isAllowed(toSparkPrivilegeObject(r)))
  }

  private def toSparkPrivilegeObject(row: Row): SparkPrivilegeObject = {
    val database = row.getString(0)
    new SparkPrivilegeObject(SparkPrivilegeObjectType.DATABASE, database, database)
  }
}