Scio 0.7.0 introduces a new ScioIO[T] trait to simplify IO implementation and stubbing in JobTest. This page lists some major changes to this new API.


Avro and BigQuery logic was decoupled from scio-core as part of the refactor.

  • Before 0.7.0
  • scio-core depends on scio-avro and scio-bigquery
  • ScioContext and SCollection[T] include Avro, object, Protobuf and BigQuery IO methods out of the box
  • After 0.7.0
  • scio-core no longer depends on scio-avro and scio-bigquery
  • Import com.spotify.scio.avro._ to get Avro, object, Protobuf IO methods on ScioContext and SCollection[T]
  • Import com.spotify.scio.bigquery._ to get BigQuery IO methods on ScioContext and SCollection[T]

ScioIO[T] for JobTest

As part of the refactor TestIO[T] was replaced by ScioIO[T] for JobTest. Some of them were moved to different packages for consistency but most test code should work with minor import changes. Below is a list of ScioIO[T] implementations.

  • com.spotify.scio.avro
  • AvroIO[T]
  • ObjectFileIO[T]
  • ProtobufIO[T]
  • com.spotify.scio.bigquery
  • BigQueryIO[T]
  • TableRowJsonIO where T =:= TableRow
  • DatastoreIO where T =:= Entity
  • PubsubIO[T]
  • TextIO where T =:= String
  • CustomIO[T] for use with ScioContext#customInput and SCollection#customOutput
  • com.spotify.scio.bigtable
  • BigtableIO[T] where T =:= Row for input and T =:= Mutation for output
  • This replaces BigtableInput and BigtableOutput
  • com.spotify.scio.cassandra
  • CassandraIO[T]
  • com.spotify.scio.elasticsearch
  • ElasticsearchIO[T]
  • com.spotify.scio.extra.json
  • JsonIO[T]
  • com.spotify.scio.jdbc
  • JdbcIO[T]
  • com.spotify.scio.parquet.avro
  • ParquetAvroIO[T]
  • com.spotify.scio.spanner
  • SpannerIO[T]
  • com.spotify.scio.tensorflow
  • TFRecordIO where T =:= Array[Byte]
  • TFExampleIO where T =:= Example

Using ScioIO[T] directly

2 methods, ScioContext#read and SCollection#write were added to leverage ScioIO[T] directly without needing the extra ScioContext#{textFile,AvroFile,...} and SCollection#saveAs{TextFile,AvroFile,...} syntactic sugar. See WordCountScioIO and WordCountScioIOTest for concrete examples.