Backup MongoDB collection to S3 with Akka Streams and Alpakka

MongoS3Backup.scala

/*
Description:
Simple example how to backup MongoDB collection to S3.
It's so easy with Akka Streams and Alpakka :) 

Dependencies:
libraryDependencies += "com.typesafe.akka" %% "akka-stream" % "2.4.17"
libraryDependencies += "com.lightbend.akka" %% "akka-stream-alpakka-s3" % "0.6"
libraryDependencies += "org.mongodb" % "mongodb-driver-reactivestreams"  % "1.3.0"
*/

import akka.actor.ActorSystem
import akka.stream.ActorMaterializer
import akka.stream.alpakka.s3.impl.MetaHeaders
import akka.stream.alpakka.s3.scaladsl.S3Client
import akka.stream.scaladsl.{Compression, Keep, Source}
import akka.util.ByteString
import com.mongodb.reactivestreams.client.MongoClients

import scala.util.{Failure, Success}


object MongoS3Backup {

  implicit val system = ActorSystem()
  implicit val mat = ActorMaterializer()
  implicit val ec = system.dispatcher

  def main(args: Array[String]): Unit = {
    val mongoClient = MongoClients.create("mongodb://localhost:27017")
    val collectionToBackup = mongoClient.getDatabase("test").getCollection("export")

    val meta = MetaHeaders(Map("someMetadata" → "abc")) //we can add some metadata information
    val sink = S3Client().multipartUpload("supersophisticatedbucketname", "123456.json", metaHeaders = meta)

    val r =
      Source
        .fromPublisher(collectionToBackup.find())
        .map(d ⇒ d.toJson)
        .map(d ⇒ ByteString(d))
        .via(Compression.gzip)    //optional step to lower file size
        .toMat(sink)(Keep.right)         
        .run()

    r.onComplete {
      case Success(s) ⇒
        println(s)
        mongoClient.close()
        system.terminate()
      case Failure(e) ⇒
        e.printStackTrace()
        mongoClient.close()
        system.terminate()
    }
  }
}