We have added Python 3.8 support in Apache Beam 2.23.0 release[1] and established the plan to remove Python 2.7 support in 2.25.0 release[2].
I think it is in the interest of the community to reduce the overhead associated with adding and removing support of Python minor versions in Beam in the future. To do so, I opened a ticket [3] to document the process of adding/removing a Python version on the Beam website, and would like to recap the discussion on this thread. It seems that the consensus is to align support of Python versions in Beam with Python annual release cycle[4]. This means: 1. We will aim to add support for a new Python 3.x version in Beam as soon as it is released. 2. After a Python 3.x version reaches the end of support[5], we will remove support for this version in Beam, starting from the first Beam release that is cut after the end-of-support date. 3. The rules above are our default course of action, but can be adjusted on a case-by-case basis via a discussion on dev@. Please let me know if you think this needs further discussion. A corollary of 1-3 is that: - we should plan to remove support for Python 3.5 starting from 2.25.0 release, since Python 3.5 reaches[5] end-of-support on 2020-09-13, and we plan to cut 2.25.0 on 2020-09-23 according to our release calendar [6], - we can start working on adding Python 3.9 support shortly after. Thanks, Valentyn <https://www.python.org/dev/peps/pep-0602/> [1] https://beam.apache.org/blog/beam-2.23.0/ [2] https://lists.apache.org/thread.html/r4be18d50ccfc5543a34e083f3e6711f9f3711110896f109f21f4677c%40%3Cdev.beam.apache.org%3E [3] https://issues.apache.org/jira/browse/BEAM-10605 [4] https://www.python.org/dev/peps/pep-0602/ [5] https://www.python.org/downloads/ [6] https://calendar.google.com/calendar/embed?src=0p73sl034k80oob7seouanigd0%40group.calendar.google.com On Thu, May 14, 2020 at 9:56 AM Yoshiki Obata <yoshiki.ob...@gmail.com> wrote: > Thank you, Kyle and Valentyn. > > I'll update test codes to treat Python 3.5 and 3.7 as high-priority > versions at this point. > > 2020年5月12日(火) 2:10 Valentyn Tymofieiev <valen...@google.com>: > > > > I agree with the point echoed earlier that the lowest and the highest of > supported versions will probably give the most useful test signal for > possible breakages. So 3.5. and 3.7 as high-priority versions SGTM. > > > > This can change later once Beam drops 3.5 support. > > > > On Mon, May 11, 2020 at 10:05 AM Yoshiki Obata <yoshiki.ob...@gmail.com> > wrote: > >> > >> Hello again, > >> > >> Test infrastructure update is ongoing and then we should determine > >> which Python versions are high-priority. > >> > >> According to Pypi downloads stats[1], download proportion of Python > >> 3.5 is almost always greater than one of 3.6 and 3.7. > >> This situation has not changed since Robert told us Python 3.x > >> occupies nearly 40% of downloads[2] > >> > >> On the other hand, according to docker hub[3], > >> apachebeam/python3.x_sdk image downloaded the most is one of Python > >> 3.7 which was pointed by Kyle[4]. > >> > >> Considering these stats, I think high-priority versions are 3.5 and 3.7. > >> > >> Is this assumption appropriate? > >> I would like to hear your thoughts about this. > >> > >> [1] https://pypistats.org/packages/apache-beam > >> [2] > https://lists.apache.org/thread.html/r208c0d11639e790453a17249e511dbfe00a09f91bef8fcd361b4b74a%40%3Cdev.beam.apache.org%3E > >> [3] https://hub.docker.com/search?q=apachebeam%2Fpython&type=image > >> [4] > https://lists.apache.org/thread.html/r9ca9ad316dae3d60a3bf298eedbe4aeecab2b2664454cc352648abc9%40%3Cdev.beam.apache.org%3E > >> > >> 2020年5月6日(水) 12:48 Yoshiki Obata <yoshiki.ob...@gmail.com>: > >> > > >> > > Not sure how run_pylint.sh is related here - we should run linter > on the entire codebase. > >> > ah, I mistyped... I meant run_pytest.sh > >> > > >> > > I am familiar with beam_PostCommit_PythonXX suites. Is there > something specific about these suites that you wanted to know? > >> > Test suite runtime will depend on the number of tests in the suite, > >> > how many tests we run in parallel, how long they take to run. To > >> > understand the load on test infrastructure we can monitor Beam test > >> > health metrics [1]. In particular, if time in queue[2] is high, it is > >> > a sign that there are not enough Jenkins slots available to start the > >> > test suite earlier. > >> > Sorry for ambiguous question. I wanted to know how to see the load on > >> > test infrastructure. > >> > The Grafana links you showed serves my purpose. Thank you. > >> > > >> > 2020年5月6日(水) 2:35 Valentyn Tymofieiev <valen...@google.com>: > >> > > > >> > > On Mon, May 4, 2020 at 7:06 PM Yoshiki Obata < > yoshiki.ob...@gmail.com> wrote: > >> > >> > >> > >> Thank you for comment, Valentyn. > >> > >> > >> > >> > 1) We can seed the smoke test suite with typehints tests, and > add more tests later if there is a need. We can identify them by the file > path or by special attributes in test files. Identifying them using > filepath seems simpler and independent of test runner. > >> > >> > >> > >> Yes, making run_pylint.sh allow target test file paths as > arguments is > >> > >> good way if could. > >> > > > >> > > > >> > > Not sure how run_pylint.sh is related here - we should run linter > on the entire codebase. > >> > > > >> > >> > >> > >> > 3) We should reduce the code duplication across > beam/sdks/python/test-suites/$runner/py3*. I think we could move the suite > definition into a common file like > beam/sdks/python/test-suites/$runner/build.gradle perhaps, and populate > individual suites (beam/sdks/python/test-suites/$runner/py38/build.gradle) > including the common file and/or logic from PythonNature [1]. > >> > >> > >> > >> Exactly. I'll check it out. > >> > >> > >> > >> > 4) We have some tests that we run only under specific Python 3 > versions, for example: FlinkValidatesRunner test runs using Python 3.5: [2] > >> > >> > HDFS Python 3 tests are running only with Python 3.7 [3]. > Cross-language Py3 tests for Spark are running under Python 3.5[4]: , there > may be more test suites that selectively use particular versions. > >> > >> > We need to correct such suites, so that we do not tie them to a > specific Python version. I see several options here: such tests should run > either for all high-priority versions, or run only under the lowest version > among the high-priority versions. We don't have to fix them all at the > same time. In general, we should try to make it as easy as possible to > configure, whether a suite runs across all versions, all high-priority > versions, or just one version. > >> > >> > >> > >> The way of high-priority/low-priority configuration would be > useful for this. > >> > >> And which versions to be tested may be related to 5). > >> > >> > >> > >> > 5) If postcommit suites (that need to run against all versions) > still constitute too much load on the infrastructure, we may need to > investigate how to run these suites less frequently. > >> > >> > >> > >> That's certainly true, beam_PostCommit_PythonXX and > >> > >> beam_PostCommit_Python_Chicago_Taxi_(Dataflow|Flink) take about 1 > >> > >> hour. > >> > >> Does anyone have knowledge about this? > >> > > > >> > > > >> > > I am familiar with beam_PostCommit_PythonXX suites. Is there > something specific about these suites that you wanted to know? > >> > > Test suite runtime will depend on the number of tests in the > suite, how many tests we run in parallel, how long they take to run. To > understand the load on test infrastructure we can monitor Beam test health > metrics [1]. In particular, if time in queue[2] is high, it is a sign that > there are not enough Jenkins slots available to start the test suite > earlier. > >> > > > >> > > [1] http://104.154.241.245/d/D81lW0pmk/post-commit-test-reliability > >> > > [2] > http://104.154.241.245/d/_TNndF2iz/pre-commit-test-latency?orgId=1&from=1588094891600&to=1588699691600&panelId=6&fullscreen > >> > > > >> > > > >> > >> > >> > >> 2020年5月2日(土) 5:18 Valentyn Tymofieiev <valen...@google.com>: > >> > >> > > >> > >> > Hi Yoshiki, > >> > >> > > >> > >> > Thanks a lot for your help with Python 3 support so far and most > recently, with your work on Python 3.8. > >> > >> > > >> > >> > Overall the proposal sounds good to me. I see several aspects > here that we need to address: > >> > >> > > >> > >> > 1) We can seed the smoke test suite with typehints tests, and > add more tests later if there is a need. We can identify them by the file > path or by special attributes in test files. Identifying them using > filepath seems simpler and independent of test runner. > >> > >> > > >> > >> > 2) Defining high priority/low priority versions in > gradle.properties sounds good to me. > >> > >> > > >> > >> > 3) We should reduce the code duplication across > beam/sdks/python/test-suites/$runner/py3*. I think we could move the suite > definition into a common file like > beam/sdks/python/test-suites/$runner/build.gradle perhaps, and populate > individual suites (beam/sdks/python/test-suites/$runner/py38/build.gradle) > including the common file and/or logic from PythonNature [1]. > >> > >> > > >> > >> > 4) We have some tests that we run only under specific Python 3 > versions, for example: FlinkValidatesRunner test runs using Python 3.5: [2] > >> > >> > HDFS Python 3 tests are running only with Python 3.7 [3]. > Cross-language Py3 tests for Spark are running under Python 3.5[4]: , there > may be more test suites that selectively use particular versions. > >> > >> > > >> > >> > We need to correct such suites, so that we do not tie them to a > specific Python version. I see several options here: such tests should run > either for all high-priority versions, or run only under the lowest version > among the high-priority versions. We don't have to fix them all at the > same time. In general, we should try to make it as easy as possible to > configure, whether a suite runs across all versions, all high-priority > versions, or just one version. > >> > >> > > >> > >> > 5) If postcommit suites (that need to run against all versions) > still constitute too much load on the infrastructure, we may need to > investigate how to run these suites less frequently. > >> > >> > > >> > >> > [1] > https://github.com/apache/beam/blob/b78c7ed4836e44177a149155581cfa8188e8f748/sdks/python/test-suites/portable/py37/build.gradle#L19-L20 > >> > >> > [2] > https://github.com/apache/beam/blob/93181e792f648122d3b4a5080d683f21c6338132/.test-infra/jenkins/job_PostCommit_Python35_ValidatesRunner_Flink.groovy#L34 > >> > >> > [3] > https://github.com/apache/beam/blob/93181e792f648122d3b4a5080d683f21c6338132/sdks/python/test-suites/direct/py37/build.gradle#L58 > >> > >> > [4] > https://github.com/apache/beam/blob/93181e792f648122d3b4a5080d683f21c6338132/.test-infra/jenkins/job_PostCommit_CrossLanguageValidatesRunner_Spark.groovy#L44 > >> > >> > > >> > >> > On Fri, May 1, 2020 at 8:42 AM Yoshiki Obata < > yoshiki.ob...@gmail.com> wrote: > >> > >> >> > >> > >> >> Hello everyone. > >> > >> >> > >> > >> >> I'm working on Python 3.8 support[1] and now is the time for > preparing > >> > >> >> test infrastructure. > >> > >> >> According to the discussion, I've considered how to prioritize > tests. > >> > >> >> My plan is as below. I'd like to get your thoughts on this. > >> > >> >> > >> > >> >> - With all low-pri Python, apache_beam.typehints.*_test run in > the > >> > >> >> PreCommit test. > >> > >> >> New gradle task should be defined like > "preCommitPy3*-minimum". > >> > >> >> If there are essential tests for all versions other than > typehints, > >> > >> >> please point out. > >> > >> >> > >> > >> >> - With high-pri Python, the same tests as running in the current > >> > >> >> PreCommit test run for testing extensively; > "tox:py3*:preCommitPy3*", > >> > >> >> "dataflow:py3*:preCommitIT" and "dataflow:py3*:preCommitIT_V2". > >> > >> >> > >> > >> >> - Low-pri versions' whole PreCommit tests are moved to each > PostCommit tests. > >> > >> >> > >> > >> >> - High-pri and low-pri versions are defined in > gralde.properties and > >> > >> >> PreCommit/PostCommit task dependencies are built dynamically > according > >> > >> >> to them. > >> > >> >> It would be easy for switching priorities of Python versions. > >> > >> >> > >> > >> >> [1] https://issues.apache.org/jira/browse/BEAM-8494 > >> > >> >> > >> > >> >> 2020年4月4日(土) 7:51 Robert Bradshaw <rober...@google.com>: > >> > >> >> > > >> > >> >> > https://pypistats.org/packages/apache-beam is an interesting > data point. > >> > >> >> > > >> > >> >> > The good news: Python 3.x more than doubled to nearly 40% of > downloads last month. Interestingly, it looks like a good chunk of this > increase was 3.5 (which is now the most popular 3.x version by this > metric...) > >> > >> >> > > >> > >> >> > I agree with using Python EOL dates as a baseline, with the > possibility of case-by-case adjustments. Refactoring our tests to support > 3.8 without increasing the load should be our focus now. > >> > >> >> > > >> > >> >> > > >> > >> >> > On Fri, Apr 3, 2020 at 3:41 PM Valentyn Tymofieiev < > valen...@google.com> wrote: > >> > >> >> >> > >> > >> >> >> Some good news on Python 3.x support: thanks to +David Song > and +Yifan Zou we now have Python 3.8 on Jenkins, and can start working on > adding Python 3.8 support to Beam (BEAM-8494). > >> > >> >> >> > >> > >> >> >>> One interesting variable that has not being mentioned is > what versions of python 3 > >> > >> >> >>> are available to users via their distribution channels (the > linux > >> > >> >> >>> distributions they use to develop/run the pipelines). > >> > >> >> >> > >> > >> >> >> > >> > >> >> >> Good point. Looking at Ubuntu 16.04, which comes with Python > 3.5.2, we can see that the end-of-life for 16.04 is in 2024, > end-of-support is April 2021 [1]. Both of these dates are beyond the > announced Python 3.5 EOL in September 2020 [2]. I think it would be > difficult for Beam to keep Py3.5 support until these EOL dates, and users > of systems that stock old versions of Python have viable workarounds: > >> > >> >> >> - install a newer version of Python interpreter via > pyenv[3], from sources, or from alternative repositories. > >> > >> >> >> - use a docker container that comes with a newer version of > interpreter. > >> > >> >> >> - use older versions of Beam. > >> > >> >> >> > >> > >> >> >> We didn't receive feedback from user@ on how long 3.x > versions on the lower/higher end of the range should stay supported. I > would suggest for now that we plan to support all Python 3.x versions that > were released and did not reach EOL. We can discuss exceptions to this rule > on a case-by-case basis, evaluating any maintenance burden to continue > support, or stop early. > >> > >> >> >> > >> > >> >> >> We should now focus on adjusting our Python test > infrastructure to make it easy to split 3.5, 3.6, 3.7, 3.8 suites into > high-priority and low-priority suites according to the Python version. > Ideally, we should make it easy to change which versions are high/low > priority without having to change all the individual test suites, and > without losing test coverage signal. > >> > >> >> >> > >> > >> >> >> [1] https://wiki.ubuntu.com/Releases > >> > >> >> >> [2] https://devguide.python.org/#status-of-python-branches > >> > >> >> >> [3] https://github.com/pyenv/pyenv/blob/master/README.md > >> > >> >> >> > >> > >> >> >> On Fri, Feb 28, 2020 at 1:25 AM Ismaël Mejía < > ieme...@gmail.com> wrote: > >> > >> >> >>> > >> > >> >> >>> One interesting variable that has not being mentioned is > what versions of python > >> > >> >> >>> 3 are available to users via their distribution channels > (the linux > >> > >> >> >>> distributions they use to develop/run the pipelines). > >> > >> >> >>> > >> > >> >> >>> - RHEL 8 users have python 3.6 available > >> > >> >> >>> - RHEL 7 users have python 3.6 available > >> > >> >> >>> - Debian 10/Ubuntu 18.04 users have python 3.7/3.6 available > >> > >> >> >>> - Debian 9/Ubuntu 16.04 users have python 3.5 available > >> > >> >> >>> > >> > >> >> >>> > >> > >> >> >>> We should consider this when we evaluate future support > removals. > >> > >> >> >>> > >> > >> >> >>> Given that the distros that support python 3.5 are ~4y old > and since python 3.5 > >> > >> >> >>> is also losing LTS support soon is probably ok to not > support it in Beam > >> > >> >> >>> anymore as Robert suggests. > >> > >> >> >>> > >> > >> >> >>> > >> > >> >> >>> On Thu, Feb 27, 2020 at 3:57 AM Valentyn Tymofieiev < > valen...@google.com> wrote: > >> > >> >> >>>> > >> > >> >> >>>> Thanks everyone for sharing your perspectives so far. It > sounds like we can mitigate the cost of test infrastructure by having: > >> > >> >> >>>> - a selection of (fast) tests that we will want to run > against all Python versions we support. > >> > >> >> >>>> - high priority Python versions, which we will test > extensively. > >> > >> >> >>>> - infrequent postcommit test that exercise low-priority > versions. > >> > >> >> >>>> We will need test infrastructure improvements to have the > flexibility of designating versions of high-pri/low-pri and minimizing > efforts requiring adopting a new version. > >> > >> >> >>>> > >> > >> >> >>>> There is still a question of how long we want to support > old Py3.x versions. As mentioned above, I think we should not support them > beyond EOL (5 years after a release). I wonder if that is still too long. > The cost of supporting a version may include: > >> > >> >> >>>> - Developing against older Python version > >> > >> >> >>>> - Release overhead (building & storing containers, > wheels, doing release validation) > >> > >> >> >>>> - Complexity / development cost to support the quirks of > the minor versions. > >> > >> >> >>>> > >> > >> >> >>>> We can decide to drop support, after, say, 4 years, or > after usage drops below a threshold, or decide on a case-by-case basis. > Thoughts? Also asked for feedback on user@ [1] > >> > >> >> >>>> > >> > >> >> >>>> [1] > https://lists.apache.org/thread.html/r630a3b55aa8e75c68c8252ea6f824c3ab231ad56e18d916dfb84d9e8%40%3Cuser.beam.apache.org%3E > >> > >> >> >>>> > >> > >> >> >>>> On Wed, Feb 26, 2020 at 5:27 PM Robert Bradshaw < > rober...@google.com> wrote: > >> > >> >> >>>>> > >> > >> >> >>>>> On Wed, Feb 26, 2020 at 5:21 PM Valentyn Tymofieiev < > valen...@google.com> wrote: > >> > >> >> >>>>> > > >> > >> >> >>>>> > > +1 to consulting users. > >> > >> >> >>>>> > I will message user@ as well and point to this thread. > >> > >> >> >>>>> > > >> > >> >> >>>>> > > I would propose getting in warnings about 3.5 EoL > well ahead of time. > >> > >> >> >>>>> > I think we should document on our website, and in the > code (warnings) that users should not expect SDKs to be supported in Beam > beyond the EOL. If we want to have flexibility to drop support earlier than > EOL, we need to be more careful with messaging because users might > otherwise expect that support will last until EOL, if we mention EOL date. > >> > >> >> >>>>> > >> > >> >> >>>>> +1 > >> > >> >> >>>>> > >> > >> >> >>>>> > I am hoping that we can establish a consensus for when > we will be dropping support for a version, so that we don't have to discuss > it on a case by case basis in the future. > >> > >> >> >>>>> > > >> > >> >> >>>>> > > I think it would makes sense to add support for 3.8 > right away (or at least get a good sense of what work needs to be done and > what our dependency situation is like) > >> > >> >> >>>>> > https://issues.apache.org/jira/browse/BEAM-8494 is a > starting point. I tried 3.8 a while ago some dependencies were not able to > install, checked again just now. SDK is "installable" after minor changes. > Some tests don't pass. BEAM-8494 does not have an owner atm, and if anyone > is interested I'm happy to give further pointers and help get started. > >> > >> >> >>>>> > > >> > >> >> >>>>> > > For the 3.x series, I think we will get the most > signal out of the lowest and highest version, and can get by with smoke > tests + > >> > >> >> >>>>> > infrequent post-commits for the ones between. > >> > >> >> >>>>> > > >> > >> >> >>>>> > > I agree with having low-frequency tests for > low-priority versions. Low-priority versions could be determined according > to least usage. > >> > >> >> >>>>> > > >> > >> >> >>>>> > These are good ideas. Do you think we will want to have > an ability to run some (inexpensive) tests for all versions frequently > (on presubmits), or this is extra complexity that can be avoided? I am > thinking about type inference for example. Afaik inference logic is very > sensitive to the version. Would it be acceptable to catch errors there in > infrequent postcommits or an early signal will be preferred? > >> > >> >> >>>>> > >> > >> >> >>>>> This is a good example--the type inference tests are > sensitive to > >> > >> >> >>>>> version (due to using internal details and relying on the > >> > >> >> >>>>> still-evolving typing module) but also run in ~15 > seconds. I think > >> > >> >> >>>>> these should be in precommits. We just don't need to run > every test > >> > >> >> >>>>> for every version. > >> > >> >> >>>>> > >> > >> >> >>>>> > On Wed, Feb 26, 2020 at 5:17 PM Kyle Weaver < > kcwea...@google.com> wrote: > >> > >> >> >>>>> >> > >> > >> >> >>>>> >> Oh, I didn't see Robert's earlier email: > >> > >> >> >>>>> >> > >> > >> >> >>>>> >> > Currently 3.5 downloads sit at 3.7%, or about > >> > >> >> >>>>> >> > 20% of all Python 3 downloads. > >> > >> >> >>>>> >> > >> > >> >> >>>>> >> Where did these numbers come from? > >> > >> >> >>>>> >> > >> > >> >> >>>>> >> On Wed, Feb 26, 2020 at 5:15 PM Kyle Weaver < > kcwea...@google.com> wrote: > >> > >> >> >>>>> >>> > >> > >> >> >>>>> >>> > I agree with having low-frequency tests for > low-priority versions. > >> > >> >> >>>>> >>> > Low-priority versions could be determined according > to least usage. > >> > >> >> >>>>> >>> > >> > >> >> >>>>> >>> +1. While the difference may not be as great between, > say, 3.6 and 3.7, I think that if we had to choose, it would be more useful > to test the versions folks are actually using the most. 3.5 only has about > a third of the Docker pulls of 3.6 or 3.7 [1]. Does anyone have other usage > statistics we can consult? > >> > >> >> >>>>> >>> > >> > >> >> >>>>> >>> [1] > https://hub.docker.com/search?q=apachebeam%2Fpython&type=image > >> > >> >> >>>>> >>> > >> > >> >> >>>>> >>> On Wed, Feb 26, 2020 at 5:00 PM Ruoyun Huang < > ruo...@google.com> wrote: > >> > >> >> >>>>> >>>> > >> > >> >> >>>>> >>>> I feel 4+ versions take too long to run anything. > >> > >> >> >>>>> >>>> > >> > >> >> >>>>> >>>> would vote for lowest + highest, 2 versions. > >> > >> >> >>>>> >>>> > >> > >> >> >>>>> >>>> On Wed, Feb 26, 2020 at 4:52 PM Udi Meiri < > eh...@google.com> wrote: > >> > >> >> >>>>> >>>>> > >> > >> >> >>>>> >>>>> I agree with having low-frequency tests for > low-priority versions. > >> > >> >> >>>>> >>>>> Low-priority versions could be determined according > to least usage. > >> > >> >> >>>>> >>>>> > >> > >> >> >>>>> >>>>> > >> > >> >> >>>>> >>>>> > >> > >> >> >>>>> >>>>> On Wed, Feb 26, 2020 at 4:06 PM Robert Bradshaw < > rober...@google.com> wrote: > >> > >> >> >>>>> >>>>>> > >> > >> >> >>>>> >>>>>> On Wed, Feb 26, 2020 at 3:29 PM Kenneth Knowles < > k...@apache.org> wrote: > >> > >> >> >>>>> >>>>>> > > >> > >> >> >>>>> >>>>>> > Are these divergent enough that they all need to > consume testing resources? For example can lower priority versions be daily > runs or some such? > >> > >> >> >>>>> >>>>>> > >> > >> >> >>>>> >>>>>> For the 3.x series, I think we will get the most > signal out of the > >> > >> >> >>>>> >>>>>> lowest and highest version, and can get by with > smoke tests + > >> > >> >> >>>>> >>>>>> infrequent post-commits for the ones between. > >> > >> >> >>>>> >>>>>> > >> > >> >> >>>>> >>>>>> > Kenn > >> > >> >> >>>>> >>>>>> > > >> > >> >> >>>>> >>>>>> > On Wed, Feb 26, 2020 at 3:25 PM Robert Bradshaw < > rober...@google.com> wrote: > >> > >> >> >>>>> >>>>>> >> > >> > >> >> >>>>> >>>>>> >> +1 to consulting users. Currently 3.5 downloads > sit at 3.7%, or about > >> > >> >> >>>>> >>>>>> >> 20% of all Python 3 downloads. > >> > >> >> >>>>> >>>>>> >> > >> > >> >> >>>>> >>>>>> >> I would propose getting in warnings about 3.5 > EoL well ahead of time, > >> > >> >> >>>>> >>>>>> >> at the very least as part of the 2.7 warning. > >> > >> >> >>>>> >>>>>> >> > >> > >> >> >>>>> >>>>>> >> Fortunately, supporting multiple 3.x versions > is significantly easier > >> > >> >> >>>>> >>>>>> >> than spanning 2.7 and 3.x. I would rather not > impose an ordering on > >> > >> >> >>>>> >>>>>> >> dropping 3.5 and adding 3.8 but consider their > merits independently. > >> > >> >> >>>>> >>>>>> >> > >> > >> >> >>>>> >>>>>> >> > >> > >> >> >>>>> >>>>>> >> On Wed, Feb 26, 2020 at 3:16 PM Kyle Weaver < > kcwea...@google.com> wrote: > >> > >> >> >>>>> >>>>>> >> > > >> > >> >> >>>>> >>>>>> >> > 5 versions is too many IMO. We've had issues > with Python precommit resource usage in the past, and adding another > version would surely exacerbate those issues. And we have also already had > to leave out certain features on 3.5 [1]. Therefore, I am in favor of > dropping 3.5 before adding 3.8. After dropping Python 2 and adding 3.8, > that will leave us with the latest three minor versions (3.6, 3.7, 3.8), > which I think is closer to the "sweet spot." Though I would be interested > in hearing if there are any users who would prefer we continue supporting > 3.5. > >> > >> >> >>>>> >>>>>> >> > > >> > >> >> >>>>> >>>>>> >> > [1] > https://github.com/apache/beam/blob/8658b95545352e51f35959f38334f3c7df8b48eb/sdks/python/apache_beam/runners/portability/flink_runner.py#L55 > >> > >> >> >>>>> >>>>>> >> > > >> > >> >> >>>>> >>>>>> >> > On Wed, Feb 26, 2020 at 3:00 PM Valentyn > Tymofieiev <valen...@google.com> wrote: > >> > >> >> >>>>> >>>>>> >> >> > >> > >> >> >>>>> >>>>>> >> >> I would like to start a discussion about > identifying a guideline for answering questions like: > >> > >> >> >>>>> >>>>>> >> >> > >> > >> >> >>>>> >>>>>> >> >> 1. When will Beam support a new Python > version (say, Python 3.8)? > >> > >> >> >>>>> >>>>>> >> >> 2. When will Beam drop support for an old > Python version (say, Python 3.5)? > >> > >> >> >>>>> >>>>>> >> >> 3. How many Python versions should we aim to > support concurrently (investigate issues, have continuous integration > tests)? > >> > >> >> >>>>> >>>>>> >> >> 4. What comes first: adding support for a > new version (3.8) or deprecating older one (3.5)? This may affect the max > load our test infrastructure needs to sustain. > >> > >> >> >>>>> >>>>>> >> >> > >> > >> >> >>>>> >>>>>> >> >> We are already getting requests for > supporting Python 3.8 and there were some good reasons[1] to drop support > for Python 3.5 (at least, early versions of 3.5). Answering these questions > would help set expectations in Beam user community, Beam dev community, > and may help us establish resource requirements for test infrastructure > and plan efforts. > >> > >> >> >>>>> >>>>>> >> >> > >> > >> >> >>>>> >>>>>> >> >> PEP-0602 [2] establishes a yearly release > cycle for Python versions starting from 3.9. Each release is a long-term > support release and is supported for 5 years: first 1.5 years allow for > general bug fix support, remaining 3.5 years have security fix support. > >> > >> >> >>>>> >>>>>> >> >> > >> > >> >> >>>>> >>>>>> >> >> At every point, there may be up to 5 Python > minor versions that did not yet reach EOL, see "Release overlap with 12 > month diagram" [3]. We can try to support all of them, but that may come at > a cost of velocity: we will have more tests to maintain, and we will have > to develop Beam against a lower version for a longer period. Supporting > less versions will have implications for user experience. It also may be > difficult to ensure support of the most recent version early, since our > dependencies (e.g. picklers) may not be supporting them yet. > >> > >> >> >>>>> >>>>>> >> >> > >> > >> >> >>>>> >>>>>> >> >> Currently we support 4 Python versions (2.7, > 3.5, 3.6, 3.7). > >> > >> >> >>>>> >>>>>> >> >> > >> > >> >> >>>>> >>>>>> >> >> Is 4 versions a sweet spot? Too much? Too > little? What do you think? > >> > >> >> >>>>> >>>>>> >> >> > >> > >> >> >>>>> >>>>>> >> >> [1] > https://github.com/apache/beam/pull/10821#issuecomment-590167711 > >> > >> >> >>>>> >>>>>> >> >> [2] > https://www.python.org/dev/peps/pep-0602/ > >> > >> >> >>>>> >>>>>> >> >> [3] > https://www.python.org/dev/peps/pep-0602/#id17 >
