On Thu, Jan 19, 2017 at 11:56 PM, Dan Halperin <dhalp...@google.com.invalid> wrote: > I do not think that Python SDK yet meets the bar [1] for implementing the > Beam model -- supporting Unbounded data is very important. That said, given > the committed and sustained set of contributors, it generally makes sense > to me to make an exception in anticipation of these features being fleshed > out soon; including potentially new users/contributors that would arrive > once in master. > > [1] https://lists.apache.org/thread.html/CAAzyFAxcmexUQnbF=Y > k0plmm3f5e5bqwjz4+c5doruclnxo...@mail.gmail.com
That is a valid point. The Python SDK supports all the unbounded parts of the model except for unbounded sources, which was deferred while seeing how https://s.apache.org/splittable-do-fn played out. I've been working with the team and merging/reviewing most of their code, and have full confidence this will be coming (and on that note can vouch for a healthy community and support which are much harder to add later). In short, I think it has the required maturity, and I'm in favor of merging soonish. > On Wed, Jan 18, 2017 at 12:24 AM, Ahmet Altay <al...@google.com.invalid> > wrote: > >> Thank you all for the comments so far. I would follow the process as >> suggested by Davor and others in this thread. >> >> Ahmet >> >> On Tue, Jan 17, 2017 at 11:47 PM, Sergio Fernández <wik...@apache.org> >> wrote: >> >> > Hi >> > >> > On Tue, Jan 17, 2017 at 5:22 PM, Ahmet Altay <al...@google.com.invalid> >> > wrote: >> > > >> > > tl;dr: I would like to start a discussion about merging python-sdk >> branch >> > > to master branch. Python SDK is mature enough and merging it to master >> > will >> > > accelerate its development and adoption. >> > > >> > >> > Good point, Ahmet! >> > >> > I've following closed the development since it was imported in June. For >> > the prototypes I've implemented so far it works quite well; I guess we'd >> > just need to focus the next months in bringing more runners support. >> > >> > With a great effort from a lot of contributors(*), Python SDK [1] is now >> a >> > > mostly complete, tested, performant Python implementation of the Beam >> > > model. Since June, when we first started with Python SDK in Apache Beam >> > we >> > > have been continuously improving it. >> > > >> > >> > I wouldn't merge during the preparation of 0.5.0 release, but after that >> > could be a good time to merge back into master. >> > >> > >> > ** Python SDK currently supports: >> > > >> > > * Model: All main concepts are present (ParDo, GroupByKey, Windowing >> > etc.). >> > > * IO: There are extensible APIs for writing new bounded sources and >> > sinks. >> > > Implementations are provided for Text, Avro, BigQuery, and Datastore. >> > > * Runners: Python SDK has an extensible base runner module that allows >> > > building specific runners on top of it. The SDK comes with two pipeline >> > > runners: DirectRunner and DataflowRunner; and it is possible to add >> more. >> > > The existing runners are currently limited to bounded execution and >> > > otherwise equivalent to their Java SDK counterparts in functionality. >> > > >> > >> > What would the effort of porting, and maintaining, parallel versions of >> the >> > Java runners? I guess I'd need to dig deeper in the model, but this may >> > represent a major effort for the project, right? >> > >> >> It is somewhat higher for DirectRunner because DirectRunner also implements >> the code for execution. It is not that high for DataflowRunner because the >> base runner module has a lot of helpers with the right hooks for >> implementing a generic runner. I would _expect_ the experience in general >> would be similar to the latter. >> >> >> > >> > >> > >> > > * Testing: Python SDK implements ValidatesRunner test framework for >> > > implementing integration test for current and future runners. There is >> > unit >> > > test coverage for all modules, and a number of integrations test for >> > > validating existing runners. >> > > * Documentation and examples: Documentation work has started on Python >> > SDK. >> > > Beam Programming Guide page has been updated to include Python [2]. The >> > > code comes with many ready to use examples and we are in a good place >> to >> > > start documenting those on the website. >> > > >> > > ** We are not done yet, next on the roadmap we have: >> > > >> > > * Streaming: Both of the existing runners lack support for streaming >> > > execution, and currently there is work going on for adding streaming >> > > support to DirectRunner [3]. >> > > * Documentation: Filling the rest of the Beam documentations with >> Python >> > > SDK specific information and examples. >> > > * SDK consistency: Making Python SDK consistent with the Java SDK. We >> > have >> > > come a long way on this and have only a few items left [4]. >> > > * Beamifying: We have been working on removing Dataflow-specific >> > references >> > > both from the documentation and from the code. There is some work left, >> > and >> > > we are currently working on those as well [5]. >> > > >> > > ** Steps and implications of merging to master: >> > > >> > > * Master branch is merged to python-sdk branch at regular intervals and >> > the >> > > last merge was on 12/22. All the past merges were uneventful because >> > there >> > > is a minimal overlap in modified files between branches. Integrating >> > > python-sdk to master will similarly touch a small number of existing >> > files. >> > > >> > > * Python SDK is using the same tools for building and testing. It is >> > > already integrated with Maven, Jenkins and Travis. Specifically the >> > impact >> > > to the testing infrastructure would be: >> > > - There will be two additional test configurations in Travis. Since >> > Travis >> > > runs all configurations in parallel there should not be a noticeable >> > change >> > > in the Travis run time. >> > > - Jenkins pre-commit test will start running the Python SDK tests. It >> > will >> > > add an additional 5 minutes to the completion time of pre-commit test. >> > > Historically Python SDK tests were not flaky and did not cause any >> random >> > > failures. >> > > - Jenkins Python post-commit test is already separated from the other >> > > post-commit tests and will continue to exist. It would not change the >> > > testing time for any other test. >> > > >> > > * The release process needs to be updated to accommodate releasing >> Python >> > > artifacts. Python SDK would fit in the existing release schedule and >> > could >> > > be released along with the Java SDK. The additional steps would >> include: >> > > - Generating Python artifacts. This could be done with a single command >> > > using Maven today. >> > > - Publishing the artifacts to a central repository such as PyPI. >> > > >> > >> > I'm more than happy to help on this. We left on purpose some things open >> > when we added Maven support to the Python build. >> > >> >> That would be awesome. We can coordinate on that post-merge. >> >> >> > >> > >> > >> > > - Updating the release guide to reflect the changes above. >> > > >> > > * Users: There are existing users using the Python SDK. To give a rough >> > > estimate, a distribution of the Beam Python SDK had a total of 23K >> > > downloads in the past 6 months [6]. Some of those users are already >> > engaged >> > > with the community (e.g. [7]). There might be an increased amount >> > > engagement from the rest of them after the merge. >> > > >> > >> > Python 3 support is something we definitively need to look ahead. I'd try >> > to make the codebase compatible with both 2.7.x and 3.6.x, rather than >> > using other solutions like 2to3. >> > >> >> I agree with you. I think it makes more sense to make codebase compatible >> with both. As you mentioned Python 3 support is not a short-term goal in >> the roadmap, and we can discuss it more as we approach that. >> >> >> > >> > >> > Looking forward to hearing your thoughts and comments on “graduating” >> > > python-sdk to the master. >> > > >> > > Thank you, >> > > Ahmet >> > > >> > > (*) Python SDK branch currently has a diverse group of contributors. >> > > Regular contributors include Charles Chen, Chamikara Jayalath, María >> > García >> > > Herrero, Mark Liu, Pablo Estrada, Robert Bradshaw (Apache Beam PMC), >> > > Sourabh Bajaj, and Vikas Kedigehalli. We have also had contributions >> from >> > > Abdullah Bashir, Marco Buccini, Sergio Fernández, Seunghyun Lee, and >> > > Younghee Kwon. >> > > >> > > [1] https://github.com/apache/beam/tree/python-sdk/sdks/python >> > > [2] https://beam.apache.org/documentation/programming-guide/ >> > > [3] https://issues.apache.org/jira/browse/BEAM-1265 >> > > [4] >> > > https://issues.apache.org/jira/issues/?jql=status%20%3D%20Op >> > > en%20AND%20labels%20%3D%20sdk-consistency >> > > [5] https://issues.apache.org/jira/browse/BEAM-1218 >> > > [6] https://pypi.python.org/pypi/google-cloud-dataflow/json >> > > [7] https://issues.apache.org/jira/browse/BEAM-1251 >> > > >> > >> > >> > Great summary, Ahmet. Thanks. >> > >> > Cheers, >> > >> > -- >> > Sergio Fernández >> > Partner Technology Manager >> > Redlink GmbH >> > m: +43 6602747925 >> > e: sergio.fernan...@redlink.co >> > w: http://redlink.co >> > >>
