How to use Spark Dataset with Thrift

Question

My data format is determined using apache thrift, with code generated by scrooge. I keep it in sparking using parquet, very similar to what is explained in this blog .

I can easily read this data into a DataFrame simply by doing:

val df = sqlContext.read.parquet("/path/to/data")

And I can read it in RDD with a bit more gymnastics:

def loadRdd[V <: TBase[_, _]](inputDirectory: String, vClass: Class[V]): RDD[V] = {
    implicit val ctagV: ClassTag[V] = ClassTag(vClass)
    ParquetInputFormat.setReadSupportClass(jobConf, classOf[ThriftReadSupport[V]])
    ParquetThriftInputFormat.setThriftClass(jobConf, vClass)
    val rdd = sc.newAPIHadoopFile(
      inputDirectory, classOf[ParquetThriftInputFormat[V]], classOf[Void], vClass, jobConf)
    rdd.asInstanceOf[NewHadoopRDD[Void, V]].values
  }
loadRdd("/path/to/data", classOf[MyThriftClass])

My question is: how can I access this data in a new Api dataset released using spark 1.6? The reason I want it is the advantages of the api dataset: type of security with the same data rate.

, - Encoder, case, (java scala , ), case, .

, :

val df = sqlContext.read.parquet("/path/to/data")

df.as[MyJavaThriftClass]

<console>:25: error: Unable to find encoder for type stored in a Dataset.  Primitive types (Int, String, etc) and Product types (case classes) are supported by importing sqlContext.implicits._  Support for serializing other types will be added in future releases.

df.as[MyScalaThriftClass]

scala.ScalaReflectionException: <none> is not a term
  at scala.reflect.api.Symbols$SymbolApi$class.asTerm(Symbols.scala:199)
  at scala.reflect.internal.Symbols$SymbolContextApiImpl.asTerm(Symbols.scala:84)
  at org.apache.spark.sql.catalyst.ScalaReflection$.org$apache$spark$sql$catalyst$ScalaReflection$$extractorFor(ScalaReflection.scala:492)
  at org.apache.spark.sql.catalyst.ScalaReflection$.extractorsFor(ScalaReflection.scala:394)
  at org.apache.spark.sql.catalyst.encoders.ExpressionEncoder$.apply(ExpressionEncoder.scala:54)
  at org.apache.spark.sql.SQLImplicits.newProductEncoder(SQLImplicits.scala:41)
  ... 48 elided


df.as[MyScalaThriftClass.Immutable]

java.lang.UnsupportedOperationException: No Encoder found for org.apache.thrift.protocol.TField
- field (class: "org.apache.thrift.protocol.TField", name: "field")
- array element class: "com.twitter.scrooge.TFieldBlob"
- field (class: "scala.collection.immutable.Map", name: "_passthroughFields")
- root class: "com.worldsense.scalathrift.ThriftRange.Immutable"
  at org.apache.spark.sql.catalyst.ScalaReflection$.org$apache$spark$sql$catalyst$ScalaReflection$$extractorFor(ScalaReflection.scala:597)
  at org.apache.spark.sql.catalyst.ScalaReflection$$anonfun$org$apache$spark$sql$catalyst$ScalaReflection$$extractorFor$1.apply(ScalaReflection.scala:509)
  at org.apache.spark.sql.catalyst.ScalaReflection$$anonfun$org$apache$spark$sql$catalyst$ScalaReflection$$extractorFor$1.apply(ScalaReflection.scala:502)
  at scala.collection.immutable.List.flatMap(List.scala:327)
  at org.apache.spark.sql.catalyst.ScalaReflection$.org$apache$spark$sql$catalyst$ScalaReflection$$extractorFor(ScalaReflection.scala:502)
  at org.apache.spark.sql.catalyst.ScalaReflection$.toCatalystArray$1(ScalaReflection.scala:419)
  at org.apache.spark.sql.catalyst.ScalaReflection$.org$apache$spark$sql$catalyst$ScalaReflection$$extractorFor(ScalaReflection.scala:537)
  at org.apache.spark.sql.catalyst.ScalaReflection$$anonfun$org$apache$spark$sql$catalyst$ScalaReflection$$extractorFor$1.apply(ScalaReflection.scala:509)
  at org.apache.spark.sql.catalyst.ScalaReflection$$anonfun$org$apache$spark$sql$catalyst$ScalaReflection$$extractorFor$1.apply(ScalaReflection.scala:502)
  at scala.collection.immutable.List.flatMap(List.scala:327)
  at org.apache.spark.sql.catalyst.ScalaReflection$.org$apache$spark$sql$catalyst$ScalaReflection$$extractorFor(ScalaReflection.scala:502)
  at org.apache.spark.sql.catalyst.ScalaReflection$.extractorsFor(ScalaReflection.scala:394)
  at org.apache.spark.sql.catalyst.encoders.ExpressionEncoder$.apply(ExpressionEncoder.scala:54)
  at org.apache.spark.sql.SQLImplicits.newProductEncoder(SQLImplicits.scala:41)
  ... 48 elided

, , Thrift, , , -, api .

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