bio.ferlab.datalake.spark3.etl.v4.TransformationsETL.scala Maven / Gradle / Ivy

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Library built on top of Apache Spark to speed-up data lakes development..

There is a newer version: 14.8.0

package bio.ferlab.datalake.spark3.etl.v4

import bio.ferlab.datalake.commons.config.{Configuration, DatasetConf, ETLContext}
import bio.ferlab.datalake.spark3.transformation.Transformation
import org.apache.spark.sql.DataFrame

class TransformationsETL[T, C <: Configuration](context: ETLContext[T, C],
                                                val source: DatasetConf,
                                                override val mainDestination: DatasetConf,
                                                val transformations: List[Transformation])
  extends SingleETL(context) {

  override def extract(lastRunValue: T,
                       currentRunValue: T): Map[String, DataFrame] = {
    log.info(s"extracting: ${source.location}")
    Map(source.id -> spark.read.format(source.format.sparkFormat).options(source.readoptions).load(source.location))
  }

  override def transformSingle(data: Map[String, DataFrame],
                               lastRunValue: T,
                               currentRunValue: T): DataFrame = {
    log.info(s"transforming: ${source.id} to ${mainDestination.id}")
    //apply list of transformations to the input data
    val finalDf = Transformation.applyTransformations(data(source.id), transformations).persist()

    log.info(s"unique ids: ${finalDf.dropDuplicates(mainDestination.keys).count()}")
    log.info(s"rows: ${finalDf.count()}")
    finalDf
  }
}