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/*
* 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 java.util.Locale
import org.apache.spark.sql.{AnalysisException, Row, SparkSession}
import org.apache.spark.sql.catalyst.FunctionIdentifier
import org.apache.spark.sql.catalyst.analysis.{FunctionRegistry, NoSuchFunctionException}
import org.apache.spark.sql.catalyst.catalog.{CatalogFunction, FunctionResource}
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 [OR REPLACE] TEMPORARY FUNCTION functionName
* AS className [USING JAR\FILE 'uri' [, JAR|FILE 'uri']]
* }}}
*
* To create a permanent function, the syntax in SQL is:
* {{{
* CREATE [OR REPLACE] FUNCTION [IF NOT EXISTS] [databaseName.]functionName
* AS className [USING JAR\FILE 'uri' [, JAR|FILE 'uri']]
* }}}
*
* @param ignoreIfExists: When true, ignore if the function with the specified name exists
* in the specified database.
* @param replace: When true, alter the function with the specified name
*/
case class CreateFunctionCommand(
databaseName: Option[String],
functionName: String,
className: String,
resources: Seq[FunctionResource],
isTemp: Boolean,
ignoreIfExists: Boolean,
replace: Boolean)
extends RunnableCommand {
if (ignoreIfExists && replace) {
throw new AnalysisException("CREATE FUNCTION with both IF NOT EXISTS and REPLACE" +
" is not allowed.")
}
// Disallow to define a temporary function with `IF NOT EXISTS`
if (ignoreIfExists && isTemp) {
throw new AnalysisException(
"It is not allowed to define a TEMPORARY function with IF NOT EXISTS.")
}
// Temporary function names should not contain database prefix like "database.function"
if (databaseName.isDefined && isTemp) {
throw new AnalysisException(s"Specifying a database in CREATE TEMPORARY FUNCTION " +
s"is not allowed: '${databaseName.get}'")
}
override def run(sparkSession: SparkSession): Seq[Row] = {
val catalog = sparkSession.sessionState.catalog
val func = CatalogFunction(FunctionIdentifier(functionName, databaseName), className, resources)
if (isTemp) {
// We first load resources and then put the builder in the function registry.
catalog.loadFunctionResources(resources)
catalog.registerFunction(func, overrideIfExists = replace)
} else {
// Handles `CREATE OR REPLACE FUNCTION AS ... USING ...`
if (replace && catalog.functionExists(func.identifier)) {
// alter the function in the metastore
catalog.alterFunction(func)
} 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.
catalog.createFunction(func, ignoreIfExists)
}
}
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 DescribeFunctionCommand(
functionName: FunctionIdentifier,
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) {
"N/A."
} 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.funcName.toLowerCase(Locale.ROOT) match {
case "<>" =>
Row(s"Function: $functionName") ::
Row("Usage: expr1 <> expr2 - " +
"Returns true if `expr1` is not equal to `expr2`.") :: Nil
case "!=" =>
Row(s"Function: $functionName") ::
Row("Usage: expr1 != expr2 - " +
"Returns true if `expr1` is not equal to `expr2`.") :: Nil
case "between" =>
Row("Function: between") ::
Row("Usage: expr1 [NOT] BETWEEN expr2 AND expr3 - " +
"evaluate if `expr1` is [not] in between `expr2` and `expr3`.") :: Nil
case "case" =>
Row("Function: case") ::
Row("Usage: CASE expr1 WHEN expr2 THEN expr3 " +
"[WHEN expr4 THEN expr5]* [ELSE expr6] END - " +
"When `expr1` = `expr2`, returns `expr3`; " +
"when `expr1` = `expr4`, return `expr5`; else return `expr6`.") :: Nil
case _ =>
try {
val info = sparkSession.sessionState.catalog.lookupFunctionInfo(functionName)
val name = if (info.getDb != null) info.getDb + "." + info.getName else info.getName
val result =
Row(s"Function: $name") ::
Row(s"Class: ${info.getClassName}") ::
Row(s"Usage: ${replaceFunctionName(info.getUsage, info.getName)}") :: Nil
if (isExtended) {
result :+
Row(s"Extended Usage:${replaceFunctionName(info.getExtended, info.getName)}")
} else {
result
}
} catch {
case _: NoSuchFunctionException => Seq(Row(s"Function: $functionName not found."))
}
}
}
}
/**
* The DDL command that drops a function.
* ifExists: returns an error if the function doesn't exist, unless this is true.
* isTemp: indicates if it is a temporary function.
*/
case class DropFunctionCommand(
databaseName: Option[String],
functionName: String,
ifExists: Boolean,
isTemp: Boolean)
extends RunnableCommand {
override def run(sparkSession: SparkSession): Seq[Row] = {
val catalog = sparkSession.sessionState.catalog
if (isTemp) {
if (databaseName.isDefined) {
throw new AnalysisException(s"Specifying a database in DROP TEMPORARY FUNCTION " +
s"is not allowed: '${databaseName.get}'")
}
if (FunctionRegistry.builtin.functionExists(FunctionIdentifier(functionName))) {
throw new AnalysisException(s"Cannot drop native function '$functionName'")
}
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".
*/
case class ShowFunctionsCommand(
db: Option[String],
pattern: Option[String],
showUserFunctions: Boolean,
showSystemFunctions: Boolean) 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("*"))
.collect {
case (f, "USER") if showUserFunctions => f.unquotedString
case (f, "SYSTEM") if showSystemFunctions => f.unquotedString
}
functionNames.sorted.map(Row(_))
}
}
