/*
* 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.spark.sql.execution.command
import org.apache.spark.sql.{AnalysisException, Row, SparkSession}
import org.apache.spark.sql.catalyst.FunctionIdentifier
import org.apache.spark.sql.catalyst.catalog.CatalogFunction
import org.apache.spark.sql.catalyst.expressions.{Attribute, ExpressionInfo}
import org.apache.spark.sql.types.{StringType, StructField, StructType}
/**
* The DDL command that creates a function.
* To create a temporary function, the syntax of using this command in SQL is:
* {{{
* CREATE TEMPORARY FUNCTION functionName
* AS className [USING JAR\FILE 'uri' [, JAR|FILE 'uri']]
* }}}
*
* To create a permanent function, the syntax in SQL is:
* {{{
* CREATE FUNCTION [databaseName.]functionName
* AS className [USING JAR\FILE 'uri' [, JAR|FILE 'uri']]
* }}}
*/
// TODO: Use Seq[FunctionResource] instead of Seq[(String, String)] for resources.
case class CreateFunction(
databaseName: Option[String],
functionName: String,
className: String,
resources: Seq[(String, String)],
isTemp: Boolean)
extends RunnableCommand {
override def run(sparkSession: SparkSession): Seq[Row] = {
val catalog = sparkSession.sessionState.catalog
if (isTemp) {
if (databaseName.isDefined) {
throw new AnalysisException(s"Specifying a database in CREATE TEMPORARY FUNCTION " +
s"is not allowed: '${databaseName.get}'")
}
// We first load resources and then put the builder in the function registry.
// Please note that it is allowed to overwrite an existing temp function.
catalog.loadFunctionResources(resources)
val info = new ExpressionInfo(className, functionName)
val builder = catalog.makeFunctionBuilder(functionName, className)
catalog.createTempFunction(functionName, info, builder, ignoreIfExists = false)
} else {
// For a permanent, we will store the metadata into underlying external catalog.
// This function will be loaded into the FunctionRegistry when a query uses it.
// We do not load it into FunctionRegistry right now.
// TODO: should we also parse "IF NOT EXISTS"?
catalog.createFunction(
CatalogFunction(FunctionIdentifier(functionName, databaseName), className, resources),
ignoreIfExists = false)
}
Seq.empty[Row]
}
}
/**
* A command for users to get the usage of a registered function.
* The syntax of using this command in SQL is
* {{{
* DESCRIBE FUNCTION [EXTENDED] upper;
* }}}
*/
case class DescribeFunction(
functionName: String,
isExtended: Boolean) extends RunnableCommand {
override val output: Seq[Attribute] = {
val schema = StructType(StructField("function_desc", StringType, nullable = false) :: Nil)
schema.toAttributes
}
private def replaceFunctionName(usage: String, functionName: String): String = {
if (usage == null) {
"To be added."
} else {
usage.replaceAll("_FUNC_", functionName)
}
}
override def run(sparkSession: SparkSession): Seq[Row] = {
// Hard code "<>", "!=", "between", and "case" for now as there is no corresponding functions.
functionName.toLowerCase match {
case "<>" =>
Row(s"Function: $functionName") ::
Row(s"Usage: a <> b - Returns TRUE if a is not equal to b") :: Nil
case "!=" =>
Row(s"Function: $functionName") ::
Row(s"Usage: a != b - Returns TRUE if a is not equal to b") :: Nil
case "between" =>
Row(s"Function: between") ::
Row(s"Usage: a [NOT] BETWEEN b AND c - " +
s"evaluate if a is [not] in between b and c") :: Nil
case "case" =>
Row(s"Function: case") ::
Row(s"Usage: CASE a WHEN b THEN c [WHEN d THEN e]* [ELSE f] END - " +
s"When a = b, returns c; when a = d, return e; else return f") :: Nil
case _ => sparkSession.sessionState.functionRegistry.lookupFunction(functionName) match {
case Some(info) =>
val result =
Row(s"Function: ${info.getName}") ::
Row(s"Class: ${info.getClassName}") ::
Row(s"Usage: ${replaceFunctionName(info.getUsage(), info.getName)}") :: Nil
if (isExtended) {
result :+
Row(s"Extended Usage:\n${replaceFunctionName(info.getExtended, info.getName)}")
} else {
result
}
case None => Seq(Row(s"Function: $functionName not found."))
}
}
}
}
/**
* The DDL command that drops a function.
* ifExists: returns an error if the function doesn't exist, unless this is true.
* isTemp: indicates if it is a temporary function.
*/
case class DropFunction(
databaseName: Option[String],
functionName: String,
ifExists: Boolean,
isTemp: Boolean)
extends RunnableCommand {
override def run(sparkSession: SparkSession): Seq[Row] = {
val catalog = sparkSession.sessionState.catalog
if (isTemp) {
if (databaseName.isDefined) {
throw new AnalysisException(s"Specifying a database in DROP TEMPORARY FUNCTION " +
s"is not allowed: '${databaseName.get}'")
}
catalog.dropTempFunction(functionName, ifExists)
} else {
// We are dropping a permanent function.
catalog.dropFunction(
FunctionIdentifier(functionName, databaseName),
ignoreIfNotExists = ifExists)
}
Seq.empty[Row]
}
}
/**
* A command for users to list all of the registered functions.
* The syntax of using this command in SQL is:
* {{{
* SHOW FUNCTIONS [LIKE pattern]
* }}}
* For the pattern, '*' matches any sequence of characters (including no characters) and
* '|' is for alternation.
* For example, "show functions like 'yea*|windo*'" will return "window" and "year".
*
* TODO currently we are simply ignore the db
*/
case class ShowFunctions(db: Option[String], pattern: Option[String]) extends RunnableCommand {
override val output: Seq[Attribute] = {
val schema = StructType(StructField("function", StringType, nullable = false) :: Nil)
schema.toAttributes
}
override def run(sparkSession: SparkSession): Seq[Row] = {
val dbName = db.getOrElse(sparkSession.sessionState.catalog.getCurrentDatabase)
// If pattern is not specified, we use '*', which is used to
// match any sequence of characters (including no characters).
val functionNames =
sparkSession.sessionState.catalog
.listFunctions(dbName, pattern.getOrElse("*"))
.map(_.unquotedString)
// The session catalog caches some persistent functions in the FunctionRegistry
// so there can be duplicates.
functionNames.distinct.sorted.map(Row(_))
}
}