[SPARK-23765][SQL] Supports custom line separator for json datasource

## What changes were proposed in this pull request?

This PR proposes to add lineSep option for a configurable line separator in text datasource.
It supports this option by using `LineRecordReader`'s functionality with passing it to the constructor.

The approach is similar with apache#20727; however, one main difference is, it uses text datasource's `lineSep` option to parse line by line in JSON's schema inference.

## How was this patch tested?

Manually tested and unit tests were added.

Author: hyukjinkwon <[email protected]>
Author: hyukjinkwon <[email protected]>

Closes apache#20877 from HyukjinKwon/linesep-json.

Author: HyukjinKwon

python/pyspark/sql/readwriter.py

@@ -176,7 +176,7 @@ def json(self, path, schema=None, primitivesAsString=None, prefersDecimal=None,
              allowComments=None, allowUnquotedFieldNames=None, allowSingleQuotes=None,
              allowNumericLeadingZero=None, allowBackslashEscapingAnyCharacter=None,
              mode=None, columnNameOfCorruptRecord=None, dateFormat=None, timestampFormat=None,
-             multiLine=None, allowUnquotedControlChars=None):
+             multiLine=None, allowUnquotedControlChars=None, lineSep=None):
         """
         Loads JSON files and returns the results as a :class:`DataFrame`.
 
@@ -237,6 +237,8 @@ def json(self, path, schema=None, primitivesAsString=None, prefersDecimal=None,
         :param allowUnquotedControlChars: allows JSON Strings to contain unquoted control
                                           characters (ASCII characters with value less than 32,
                                           including tab and line feed characters) or not.
+        :param lineSep: defines the line separator that should be used for parsing. If None is
+                        set, it covers all ``\\r``, ``\\r\\n`` and ``\\n``.
 
         >>> df1 = spark.read.json('python/test_support/sql/people.json')
         >>> df1.dtypes
@@ -254,7 +256,7 @@ def json(self, path, schema=None, primitivesAsString=None, prefersDecimal=None,
             allowBackslashEscapingAnyCharacter=allowBackslashEscapingAnyCharacter,
             mode=mode, columnNameOfCorruptRecord=columnNameOfCorruptRecord, dateFormat=dateFormat,
             timestampFormat=timestampFormat, multiLine=multiLine,
-            allowUnquotedControlChars=allowUnquotedControlChars)
+            allowUnquotedControlChars=allowUnquotedControlChars, lineSep=lineSep)
         if isinstance(path, basestring):
             path = [path]
         if type(path) == list:
@@ -746,7 +748,8 @@ def saveAsTable(self, name, format=None, mode=None, partitionBy=None, **options)
         self._jwrite.saveAsTable(name)
 
     @since(1.4)
-    def json(self, path, mode=None, compression=None, dateFormat=None, timestampFormat=None):
+    def json(self, path, mode=None, compression=None, dateFormat=None, timestampFormat=None,
+             lineSep=None):
         """Saves the content of the :class:`DataFrame` in JSON format
         (`JSON Lines text format or newline-delimited JSON <http://jsonlines.org/>`_) at the
         specified path.
@@ -770,12 +773,15 @@ def json(self, path, mode=None, compression=None, dateFormat=None, timestampForm
                                 formats follow the formats at ``java.text.SimpleDateFormat``.
                                 This applies to timestamp type. If None is set, it uses the
                                 default value, ``yyyy-MM-dd'T'HH:mm:ss.SSSXXX``.
+        :param lineSep: defines the line separator that should be used for writing. If None is
+                        set, it uses the default value, ``\\n``.
 
         >>> df.write.json(os.path.join(tempfile.mkdtemp(), 'data'))
         """
         self.mode(mode)
         self._set_opts(
-            compression=compression, dateFormat=dateFormat, timestampFormat=timestampFormat)
+            compression=compression, dateFormat=dateFormat, timestampFormat=timestampFormat,
+            lineSep=lineSep)
         self._jwrite.json(path)
 
     @since(1.4)

python/pyspark/sql/streaming.py

@@ -405,7 +405,7 @@ def json(self, path, schema=None, primitivesAsString=None, prefersDecimal=None,
              allowComments=None, allowUnquotedFieldNames=None, allowSingleQuotes=None,
              allowNumericLeadingZero=None, allowBackslashEscapingAnyCharacter=None,
              mode=None, columnNameOfCorruptRecord=None, dateFormat=None, timestampFormat=None,
-             multiLine=None,  allowUnquotedControlChars=None):
+             multiLine=None,  allowUnquotedControlChars=None, lineSep=None):
         """
         Loads a JSON file stream and returns the results as a :class:`DataFrame`.
 
@@ -468,6 +468,8 @@ def json(self, path, schema=None, primitivesAsString=None, prefersDecimal=None,
         :param allowUnquotedControlChars: allows JSON Strings to contain unquoted control
                                           characters (ASCII characters with value less than 32,
                                           including tab and line feed characters) or not.
+        :param lineSep: defines the line separator that should be used for parsing. If None is
+                        set, it covers all ``\\r``, ``\\r\\n`` and ``\\n``.
 
         >>> json_sdf = spark.readStream.json(tempfile.mkdtemp(), schema = sdf_schema)
         >>> json_sdf.isStreaming
@@ -482,7 +484,7 @@ def json(self, path, schema=None, primitivesAsString=None, prefersDecimal=None,
             allowBackslashEscapingAnyCharacter=allowBackslashEscapingAnyCharacter,
             mode=mode, columnNameOfCorruptRecord=columnNameOfCorruptRecord, dateFormat=dateFormat,
             timestampFormat=timestampFormat, multiLine=multiLine,
-            allowUnquotedControlChars=allowUnquotedControlChars)
+            allowUnquotedControlChars=allowUnquotedControlChars, lineSep=lineSep)
         if isinstance(path, basestring):
             return self._df(self._jreader.json(path))
         else:

python/pyspark/sql/tests.py

@@ -676,6 +676,23 @@ def test_multiline_json(self):
                                             multiLine=True)
         self.assertEqual(people1.collect(), people_array.collect())
 
+    def test_linesep_json(self):
+        df = self.spark.read.json("python/test_support/sql/people.json", lineSep=",")
+        expected = [Row(_corrupt_record=None, name=u'Michael'),
+                    Row(_corrupt_record=u' "age":30}\n{"name":"Justin"', name=None),
+                    Row(_corrupt_record=u' "age":19}\n', name=None)]
+        self.assertEqual(df.collect(), expected)
+
+        tpath = tempfile.mkdtemp()
+        shutil.rmtree(tpath)
+        try:
+            df = self.spark.read.json("python/test_support/sql/people.json")
+            df.write.json(tpath, lineSep="!!")
+            readback = self.spark.read.json(tpath, lineSep="!!")
+            self.assertEqual(readback.collect(), df.collect())
+        finally:
+            shutil.rmtree(tpath)
+
     def test_multiline_csv(self):
         ages_newlines = self.spark.read.csv(
             "python/test_support/sql/ages_newlines.csv", multiLine=True)

sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/json/JSONOptions.scala

@@ -17,6 +17,7 @@
 
 package org.apache.spark.sql.catalyst.json
 
+import java.nio.charset.StandardCharsets
 import java.util.{Locale, TimeZone}
 
 import com.fasterxml.jackson.core.{JsonFactory, JsonParser}
@@ -85,6 +86,16 @@ private[sql] class JSONOptions(
 
   val multiLine = parameters.get("multiLine").map(_.toBoolean).getOrElse(false)
 
+  val lineSeparator: Option[String] = parameters.get("lineSep").map { sep =>
+    require(sep.nonEmpty, "'lineSep' cannot be an empty string.")
+    sep
+  }
+  // Note that the option 'lineSep' uses a different default value in read and write.
+  val lineSeparatorInRead: Option[Array[Byte]] =
+    lineSeparator.map(_.getBytes(StandardCharsets.UTF_8))
+  // Note that JSON uses writer with UTF-8 charset. This string will be written out as UTF-8.
+  val lineSeparatorInWrite: String = lineSeparator.getOrElse("\n")
+
   /** Sets config options on a Jackson [[JsonFactory]]. */
   def setJacksonOptions(factory: JsonFactory): Unit = {
     factory.configure(JsonParser.Feature.ALLOW_COMMENTS, allowComments)

sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/json/JacksonGenerator.scala

@@ -18,6 +18,7 @@
 package org.apache.spark.sql.catalyst.json
 
 import java.io.Writer
+import java.nio.charset.StandardCharsets
 
 import com.fasterxml.jackson.core._
 
@@ -74,6 +75,8 @@ private[sql] class JacksonGenerator(
 
   private val gen = new JsonFactory().createGenerator(writer).setRootValueSeparator(null)
 
+  private val lineSeparator: String = options.lineSeparatorInWrite
+
   private def makeWriter(dataType: DataType): ValueWriter = dataType match {
     case NullType =>
       (row: SpecializedGetters, ordinal: Int) =>
@@ -251,5 +254,8 @@ private[sql] class JacksonGenerator(
       mapType = dataType.asInstanceOf[MapType]))
   }
 
-  def writeLineEnding(): Unit = gen.writeRaw('\n')
+  def writeLineEnding(): Unit = {
+    // Note that JSON uses writer with UTF-8 charset. This string will be written out as UTF-8.
+    gen.writeRaw(lineSeparator)
+  }
 }

sql/core/src/main/scala/org/apache/spark/sql/DataFrameReader.scala

@@ -366,6 +366,8 @@ class DataFrameReader private[sql](sparkSession: SparkSession) extends Logging {
    * `java.text.SimpleDateFormat`. This applies to timestamp type.</li>
    * <li>`multiLine` (default `false`): parse one record, which may span multiple lines,
    * per file</li>
+   * <li>`lineSep` (default covers all `\r`, `\r\n` and `\n`): defines the line separator
+   * that should be used for parsing.</li>
    * </ul>
    *
    * @since 2.0.0

sql/core/src/main/scala/org/apache/spark/sql/DataFrameWriter.scala

@@ -518,6 +518,8 @@ final class DataFrameWriter[T] private[sql](ds: Dataset[T]) {
    * <li>`timestampFormat` (default `yyyy-MM-dd'T'HH:mm:ss.SSSXXX`): sets the string that
    * indicates a timestamp format. Custom date formats follow the formats at
    * `java.text.SimpleDateFormat`. This applies to timestamp type.</li>
+   * <li>`lineSep` (default `\n`): defines the line separator that should
+   * be used for writing.</li>
    * </ul>
    *
    * @since 1.4.0

sql/core/src/main/scala/org/apache/spark/sql/execution/datasources/json/JsonDataSource.scala

@@ -35,7 +35,7 @@ import org.apache.spark.sql.{AnalysisException, Dataset, Encoders, SparkSession}
 import org.apache.spark.sql.catalyst.InternalRow
 import org.apache.spark.sql.catalyst.json.{CreateJacksonParser, JacksonParser, JSONOptions}
 import org.apache.spark.sql.execution.datasources._
-import org.apache.spark.sql.execution.datasources.text.TextFileFormat
+import org.apache.spark.sql.execution.datasources.text.{TextFileFormat, TextOptions}
 import org.apache.spark.sql.types.StructType
 import org.apache.spark.unsafe.types.UTF8String
 import org.apache.spark.util.Utils
@@ -92,7 +92,8 @@ object TextInputJsonDataSource extends JsonDataSource {
       sparkSession: SparkSession,
       inputPaths: Seq[FileStatus],
       parsedOptions: JSONOptions): StructType = {
-    val json: Dataset[String] = createBaseDataset(sparkSession, inputPaths)
+    val json: Dataset[String] = createBaseDataset(
+      sparkSession, inputPaths, parsedOptions.lineSeparator)
     inferFromDataset(json, parsedOptions)
   }
 
@@ -104,13 +105,19 @@ object TextInputJsonDataSource extends JsonDataSource {
 
   private def createBaseDataset(
       sparkSession: SparkSession,
-      inputPaths: Seq[FileStatus]): Dataset[String] = {
+      inputPaths: Seq[FileStatus],
+      lineSeparator: Option[String]): Dataset[String] = {
+    val textOptions = lineSeparator.map { lineSep =>
+      Map(TextOptions.LINE_SEPARATOR -> lineSep)
+    }.getOrElse(Map.empty[String, String])
+
     val paths = inputPaths.map(_.getPath.toString)
     sparkSession.baseRelationToDataFrame(
       DataSource.apply(
         sparkSession,
         paths = paths,
-        className = classOf[TextFileFormat].getName
+        className = classOf[TextFileFormat].getName,
+        options = textOptions
       ).resolveRelation(checkFilesExist = false))
       .select("value").as(Encoders.STRING)
   }
@@ -120,7 +127,7 @@ object TextInputJsonDataSource extends JsonDataSource {
       file: PartitionedFile,
       parser: JacksonParser,
       schema: StructType): Iterator[InternalRow] = {
-    val linesReader = new HadoopFileLinesReader(file, conf)
+    val linesReader = new HadoopFileLinesReader(file, parser.options.lineSeparatorInRead, conf)
     Option(TaskContext.get()).foreach(_.addTaskCompletionListener(_ => linesReader.close()))
     val safeParser = new FailureSafeParser[Text](
       input => parser.parse(input, CreateJacksonParser.text, textToUTF8String),

sql/core/src/main/scala/org/apache/spark/sql/execution/datasources/text/TextOptions.scala

@@ -52,7 +52,7 @@ private[text] class TextOptions(@transient private val parameters: CaseInsensiti
     lineSeparatorInRead.getOrElse("\n".getBytes(StandardCharsets.UTF_8))
 }
 
-private[text] object TextOptions {
+private[datasources] object TextOptions {
   val COMPRESSION = "compression"
   val WHOLETEXT = "wholetext"
   val LINE_SEPARATOR = "lineSep"

sql/core/src/main/scala/org/apache/spark/sql/streaming/DataStreamReader.scala

@@ -268,6 +268,8 @@ final class DataStreamReader private[sql](sparkSession: SparkSession) extends Lo
    * `java.text.SimpleDateFormat`. This applies to timestamp type.</li>
    * <li>`multiLine` (default `false`): parse one record, which may span multiple lines,
    * per file</li>
+   * <li>`lineSep` (default covers all `\r`, `\r\n` and `\n`): defines the line separator
+   * that should be used for parsing.</li>
    * </ul>
    *
    * @since 2.0.0