Re: [DISCUSS] How many Python 3.x minor versions should Beam Python SDK aim to support concurrently?

[Yoshiki Obata]

I've written a mini doc[1] about how to update python tests to reduce
consumption test resources.
It would be helpful to check this and comment if there are better solutions.

[1] 
https://docs.google.com/document/d/1tfCWtMxfqjgsokjRkOGh2I4UAvX8B98ZOys0crzCMiw/edit?usp=sharing

2020年7月31日(金) 9:44 Valentyn Tymofieiev :
>
> 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
>
> [1] https://beam.apache.org/blog/beam-2.23.0/
> [2] 
> https://lists.apache.org/thread.html/r4be18d50ccfc5543a34e083f3e6711f9f370896f109f21f4677c%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  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 :
>> >
>> > 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  
>> > 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 :
>> >> >
>> >> > > 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 Tymo

Re: [DISCUSS] How many Python 3.x minor versions should Beam Python SDK aim to support concurrently?

[Valentyn Tymofieiev]

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


[1] https://beam.apache.org/blog/beam-2.23.0/
[2]
https://lists.apache.org/thread.html/r4be18d50ccfc5543a34e083f3e6711f9f370896f109f21f4677c%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 
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 :
> >
> > 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 
> 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 :
> >> >
> >> > > 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 :
> >> > >
> >> > > 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.
> >> > >>
> >

Re: [DISCUSS] How many Python 3.x minor versions should Beam Python SDK aim to support concurrently?

[Yoshiki Obata]

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 :
>
> 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  
> 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 :
>> >
>> > > 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 :
>> > >
>> > > On Mon, May 4, 2020 at 7:06 PM Yoshiki Obata  
>> > > 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 

Re: [DISCUSS] How many Python 3.x minor versions should Beam Python SDK aim to support concurrently?

[Valentyn Tymofieiev]

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 
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 :
> >
> > > 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 :
> > >
> > > On Mon, May 4, 2020 at 7:06 PM Yoshiki Obata 
> 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 t

Re: [DISCUSS] How many Python 3.x minor versions should Beam Python SDK aim to support concurrently?

[Kyle Weaver]

We've since moved our official Docker images here:
https://hub.docker.com/search?q=apache%2Fbeam_python&type=image

But Docker downloads are not as representative of actual usage as PyPI.

On Mon, May 11, 2020 at 1:05 PM Yoshiki Obata 
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 :
> >
> > > 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 :
> > >
> > > On Mon, May 4, 2020 at 7:06 PM Yoshiki Obata 
> 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

Re: [DISCUSS] How many Python 3.x minor versions should Beam Python SDK aim to support concurrently?

[Yoshiki Obata]

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 :
>
> > 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 :
> >
> > On Mon, May 4, 2020 at 7:06 PM Yoshiki Obata  
> > 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://104.1

Re: [DISCUSS] How many Python 3.x minor versions should Beam Python SDK aim to support concurrently?

[Yoshiki Obata]

> 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 :
>
> On Mon, May 4, 2020 at 7:06 PM Yoshiki Obata  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 :
>> >
>> > 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) 
>> > includin

Re: [DISCUSS] How many Python 3.x minor versions should Beam Python SDK aim to support concurrently?

[Valentyn Tymofieiev]

On Mon, May 4, 2020 at 7:06 PM Yoshiki Obata 
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 :
> >
> > 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, w

Re: [DISCUSS] How many Python 3.x minor versions should Beam Python SDK aim to support concurrently?

[Yoshiki Obata]

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.

> 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?

2020年5月2日(土) 5:18 Valentyn Tymofieiev :
>
> 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  wrote:
>>
>> Hello everyone.
>>
>> I'm working on Python 3.8 support[1] and now is the time for preparing
>> test infrastructure.
>> Accor

Re: [DISCUSS] How many Python 3.x minor versions should Beam Python SDK aim to support concurrently?

[Valentyn Tymofieiev]

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 
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 :
> >
> > 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 
> 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
>

Re: [DISCUSS] How many Python 3.x minor versions should Beam Python SDK aim to support concurrently?

[Yoshiki Obata]

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 :
>
> 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  
> 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  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  
>>> 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 
 designa

Re: [DISCUSS] How many Python 3.x minor versions should Beam Python SDK aim to support concurrently?

[Robert Bradshaw]

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 
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  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 
>> 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 
>>> 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

Re: [DISCUSS] How many Python 3.x minor versions should Beam Python SDK aim to support concurrently?

[Valentyn Tymofieiev]

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  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 
> 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 
>> wrote:
>>
>>> On Wed, Feb 26, 2020 at 5:21 PM Valentyn Tymofieiev 
>>> 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 w

Re: [DISCUSS] How many Python 3.x minor versions should Beam Python SDK aim to support concurrently?

[Ismaël Mejía]

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 
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 
> wrote:
>
>> On Wed, Feb 26, 2020 at 5:21 PM Valentyn Tymofieiev 
>> 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 
>> 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 
>> wrote:
>> >>>
>> >>> > I agree with having low-frequency tests for low-priority versions.
>> >>> > Low-priority versions could be 

Re: [DISCUSS] How many Python 3.x minor versions should Beam Python SDK aim to support concurrently?

[Valentyn Tymofieiev]

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  wrote:

> On Wed, Feb 26, 2020 at 5:21 PM Valentyn Tymofieiev 
> 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  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 
> 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 
> 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  wrote:
> >
> > I agree with having low-frequency tests for low-priority versions.
> > Low-priority versions could be determined acco

Re: [DISCUSS] How many Python 3.x minor versions should Beam Python SDK aim to support concurrently?

[Robert Bradshaw]

On Wed, Feb 26, 2020 at 5:21 PM Valentyn Tymofieiev  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  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  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  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  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  
> wrote:
>>
>> On Wed, Feb 26, 2020 at 3:29 PM Kenneth Knowles  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  
>> > 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  
>> >> wrote:
>> >> >
>> >> > 5 versions is too many IMO. We've had issues with Python precommit 
>> >> > resource usage in the past, and 

Re: [DISCUSS] How many Python 3.x minor versions should Beam Python SDK aim to support concurrently?

[Robert Bradshaw]

On Wed, Feb 26, 2020 at 5:15 PM Kyle Weaver  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?

While usage is important, we should also prioritize testing resources
according to the signal we get from them. If we only tested 3.6 and
3.7 it's very easy to break 3.5 due to accidentally using new features
introduced in 3.6. (It's happened to me, fortunately we had tests :).
On the other hand, if something works in  both 3.5 and 3.7, I would be
quite surprised if it does not work in 3.6.

Pypi download stats from https://pypistats.org/packages/apache-beam

> [1] https://hub.docker.com/search?q=apachebeam%2Fpython&type=image
>
> On Wed, Feb 26, 2020 at 5:00 PM Ruoyun Huang  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  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  wrote:

 On Wed, Feb 26, 2020 at 3:29 PM Kenneth Knowles  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  
 > 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  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 
 >> >  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 

Re: [DISCUSS] How many Python 3.x minor versions should Beam Python SDK aim to support concurrently?

[Valentyn Tymofieiev]

> +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.

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?

On Wed, Feb 26, 2020 at 5:17 PM Kyle Weaver  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  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  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  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 
 wrote:

> On Wed, Feb 26, 2020 at 3:29 PM Kenneth Knowles 
> 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 
> 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 
> 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.
> >> >
> >

Re: [DISCUSS] How many Python 3.x minor versions should Beam Python SDK aim to support concurrently?

[Kyle Weaver]

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  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  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  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 
>>> wrote:
>>>
 On Wed, Feb 26, 2020 at 3:29 PM Kenneth Knowles 
 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 
 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 
 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 m

Re: [DISCUSS] How many Python 3.x minor versions should Beam Python SDK aim to support concurrently?

[Kyle Weaver]

> 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  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  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 
>> wrote:
>>
>>> On Wed, Feb 26, 2020 at 3:29 PM Kenneth Knowles  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 
>>> 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 
>>> 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/apach

Re: [DISCUSS] How many Python 3.x minor versions should Beam Python SDK aim to support concurrently?

[Ruoyun Huang]

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  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 
> wrote:
>
>> On Wed, Feb 26, 2020 at 3:29 PM Kenneth Knowles  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 
>> 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 
>> 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
>>
>

Re: [DISCUSS] How many Python 3.x minor versions should Beam Python SDK aim to support concurrently?

[Udi Meiri]

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  wrote:

> On Wed, Feb 26, 2020 at 3:29 PM Kenneth Knowles  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 
> 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 
> 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
>


smime.p7s
Description: S/MIME Cryptographic Signature

Re: [DISCUSS] How many Python 3.x minor versions should Beam Python SDK aim to support concurrently?

[Robert Bradshaw]

On Wed, Feb 26, 2020 at 3:29 PM Kenneth Knowles  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  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  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  
>> > 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

Re: [DISCUSS] How many Python 3.x minor versions should Beam Python SDK aim to support concurrently?

[Kenneth Knowles]

Are these divergent enough that they all need to consume testing resources?
For example can lower priority versions be daily runs or some such?

Kenn

On Wed, Feb 26, 2020 at 3:25 PM Robert Bradshaw  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  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 
> 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
>

Re: [DISCUSS] How many Python 3.x minor versions should Beam Python SDK aim to support concurrently?

[Robert Bradshaw]

+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  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  
> 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

Re: [DISCUSS] How many Python 3.x minor versions should Beam Python SDK aim to support concurrently?

[Kyle Weaver]

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 
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
>

Re: [DISCUSS] How many Python 3.x minor versions should Beam Python SDK aim to support concurrently?

[Robert Bradshaw]

Thanks for bringing this up. I've actually been thinking about the
same thing (specifically with regards to 3.5 and 3.8).

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), and to drop support for 3.5 soonish (in
particular, Python 3.5 is EOL 2020-09-13 [1], and also it'd be good if
users porting from Python 2.7 don't port to it).

As for testing and infrastructure, we probably don't need to test all
permutations on all releases (though exactly what the correct
subsetting should be is TBD). Likely we could run complete suites for
the oldest and newest supported version, slimmed down, cheaper
versions for the middle ones, and maybe full post-commits (which would
give us signals into what our slimmed-down coverage is).

[1] https://devguide.python.org/#status-of-python-branches

On Wed, Feb 26, 2020 at 3:00 PM Valentyn Tymofieiev  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