spark FileDataSourceV2 源码
spark FileDataSourceV2 代码
文件路径:/sql/core/src/main/scala/org/apache/spark/sql/execution/datasources/v2/FileDataSourceV2.scala
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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.datasources.v2
import java.util
import scala.collection.JavaConverters._
import com.fasterxml.jackson.databind.ObjectMapper
import com.fasterxml.jackson.module.scala.DefaultScalaModule
import org.apache.hadoop.conf.Configuration
import org.apache.hadoop.fs.Path
import org.apache.spark.sql.SparkSession
import org.apache.spark.sql.connector.catalog.{Table, TableProvider}
import org.apache.spark.sql.connector.expressions.Transform
import org.apache.spark.sql.errors.QueryExecutionErrors
import org.apache.spark.sql.execution.datasources._
import org.apache.spark.sql.sources.DataSourceRegister
import org.apache.spark.sql.types.StructType
import org.apache.spark.sql.util.CaseInsensitiveStringMap
import org.apache.spark.util.Utils
/**
* A base interface for data source v2 implementations of the built-in file-based data sources.
*/
trait FileDataSourceV2 extends TableProvider with DataSourceRegister {
/**
* Returns a V1 [[FileFormat]] class of the same file data source.
* This is a solution for the following cases:
* 1. File datasource V2 implementations cause regression. Users can disable the problematic data
* source via SQL configuration and fall back to FileFormat.
* 2. Catalog support is required, which is still under development for data source V2.
*/
def fallbackFileFormat: Class[_ <: FileFormat]
lazy val sparkSession = SparkSession.active
protected def getPaths(map: CaseInsensitiveStringMap): Seq[String] = {
val paths = Option(map.get("paths")).map { pathStr =>
FileDataSourceV2.readPathsToSeq(pathStr)
}.getOrElse(Seq.empty)
paths ++ Option(map.get("path")).toSeq
}
protected def getOptionsWithoutPaths(map: CaseInsensitiveStringMap): CaseInsensitiveStringMap = {
val withoutPath = map.asCaseSensitiveMap().asScala.filterKeys { k =>
!k.equalsIgnoreCase("path") && !k.equalsIgnoreCase("paths")
}
new CaseInsensitiveStringMap(withoutPath.toMap.asJava)
}
protected def getTableName(map: CaseInsensitiveStringMap, paths: Seq[String]): String = {
val hadoopConf = sparkSession.sessionState.newHadoopConfWithOptions(
map.asCaseSensitiveMap().asScala.toMap)
val name = shortName() + " " + paths.map(qualifiedPathName(_, hadoopConf)).mkString(",")
Utils.redact(sparkSession.sessionState.conf.stringRedactionPattern, name)
}
private def qualifiedPathName(path: String, hadoopConf: Configuration): String = {
val hdfsPath = new Path(path)
val fs = hdfsPath.getFileSystem(hadoopConf)
hdfsPath.makeQualified(fs.getUri, fs.getWorkingDirectory).toString
}
// TODO: To reduce code diff of SPARK-29665, we create stub implementations for file source v2, so
// that we don't need to touch all the file source v2 classes. We should remove the stub
// implementation and directly implement the TableProvider APIs.
protected def getTable(options: CaseInsensitiveStringMap): Table
protected def getTable(options: CaseInsensitiveStringMap, schema: StructType): Table = {
throw QueryExecutionErrors.unsupportedUserSpecifiedSchemaError()
}
override def supportsExternalMetadata(): Boolean = true
private var t: Table = null
override def inferSchema(options: CaseInsensitiveStringMap): StructType = {
if (t == null) t = getTable(options)
t.schema()
}
// TODO: implement a light-weight partition inference which only looks at the path of one leaf
// file and return partition column names. For now the partition inference happens in
// `getTable`, because we don't know the user-specified schema here.
override def inferPartitioning(options: CaseInsensitiveStringMap): Array[Transform] = {
Array.empty
}
override def getTable(
schema: StructType,
partitioning: Array[Transform],
properties: util.Map[String, String]): Table = {
// If the table is already loaded during schema inference, return it directly.
if (t != null) {
t
} else {
getTable(new CaseInsensitiveStringMap(properties), schema)
}
}
}
private object FileDataSourceV2 {
private lazy val objectMapper = new ObjectMapper().registerModule(DefaultScalaModule)
private def readPathsToSeq(paths: String): Seq[String] =
objectMapper.readValue(paths, classOf[Seq[String]])
}
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