MongoDB Shard oplog tailing source creation

Main.scala

val shardOplogSources: Seq[Source[Document, NotUsed]] = shardService.getShards.map { shard =>
    RestartSource.withBackoff(
      minBackoff = 3.seconds,
      maxBackoff = 30.seconds,
      randomFactor = 0.2, // adds 20% "noise" to vary the intervals slightly
      maxRestarts = 20 // limits the amount of restarts to 20
    ) { () =>
      oplog.source(MongoClient(shard.uri))
    }
  }