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Re: Pinning dependencies for Apache Airflow


Hi folks,

On top of this discussion, I was thinking we should have the ability to
quickly monitor dependency release as well. Previously, it happened for a
few times that CI kept failing for no reason and eventually turned out it
was due to dependency release. But it took us some time, sometimes a few
days, to realise the failure was because of dependency release.

To partially address this, I tried to develop a mini tool to help us check
the latest release of Python packages & the release date-time on PyPi. So,
by comparing it with our CI failure history, we may be able to troubleshoot
faster.

Output Sample (ordered by upload time in desc order):
                               Latest Version          Upload Time
Package Name
awscli                    1.16.28                      2018-10-05T23:12:45
botocore                1.12.18                      2018-10-05T23:12:39
promise                   2.2.1                        2018-10-04T22:04:18
Keras                     2.2.4                         2018-10-03T20:59:39
bleach                    3.0.0                        2018-10-03T16:54:27
Flask-AppBuilder         1.12.0                2018-10-03T09:03:48
... ...

It's a minimal tool (not perfect yet but working). I have hosted this tool
at https://github.com/XD-DENG/pypi-release-query.


XD

On Sat, Oct 6, 2018 at 12:25 AM Jarek Potiuk <Jarek.Potiuk@xxxxxxxxxxx>
wrote:

> Hello Erik,
>
> I understand your concern. It's a hard one to solve in general (i.e.
> dependency-hell). It looks like in this case you treat Airflow as
> 'library', where for some other people it might be more like 'end product'.
> If you look at the "pinning" philosophy - the "pin everything" is good for
> end products, but not good for libraries. In the case you have Airflow is
> treated as a bit of both. And it's perfectly valid case at that (with
> custom python DAGs being central concept for Airflow).
> However, I think it's not as bad as you think when it comes to exact
> pinning.
>
> I believe - a bit counter-intuitively - that tools like pip-tools/poetry
> with exact pinning result in having your dependencies upgraded more often,
> rather than less - especially in complex systems where dependency-hell
> creeps-in. If you look at Airflow's setup.py now - It's a bit scary to make
> any change to it. There is a chance it will blow at your face if you change
> it. You never know why there is 0.3 < ver < 1.0 - and if you change it,
> whether it will cause chain reaction of conflicts that will ruin your work
> day.
>
> On the contrary - if you change it to exact pinning in
> .lock/requirements.txt file (poetry/pip-tools) and have much simpler (and
> commented) exclusion/avoidance rules in your .in/.tml file, the whole setup
> might be much easier to maintain and upgrade. Every time you prepare for
> release (or even once in a while for master) one person might consciously
> attempt to upgrade all dependencies to latest ones. It should be almost as
> easy as letting poetry/pip-tools help with figuring out what are the latest
> set of dependencies that will work without conflicts. It should be rather
> straightforward (I've done it in the past for fairly complex systems). What
> those tools enable is - doing single-shot upgrade of all dependencies.
> After doing it you can make sure that all tests work fine (and fix any
> problems that result from it). And then you test it thoroughly before you
> make final release. You can do it in separate PR - with automated testing
> in Travis which means that you are not disturbing work of others
> (compilation/building + unit tests are guaranteed to work before you merge
> it) while doing it. It's all conscious rather than accidental. Nice side
> effect of that is that with every release you can actually "catch-up" with
> latest stable versions of many libraries in one go. It's better than
> waiting until someone deliberately upgrades to newer version (and the rest
> remain terribly out-dated as is the case for Airflow now).
>
> So a bit counterintuitively I think tools like pip-tools/poetry help you to
> catch up faster in many cases. That is at least my experience so far.
>
> Additionally, Airflow is an open system - if you have very specific needs
> for requirements, you might actually - in the very same way with
> pip-tools/poetry - upgrade all your dependencies in your local fork of
> Airflow before someone else does it in master/release. Those tools kind of
> democratise dependency management. It should be as easy as `pip-compile
> --upgrade` or `poetry update` and you will get all the "non-conflicting"
> latest dependencies in your local fork (and poetry especially seems to do
> all the heavy lifting of figuring out which versions will work). You should
> be able to test and publish it locally as your private package for local
> installations. You can even mark the specific dependency you want to use
> specific version and let pip-tools/poetry figure out exact versions of
> other requirements. You can even make a PR with such upgrade eventually to
> get it faster in master. You can even downgrade in case newer dependency
> causes problems for you in similar way. Guided by the tools, it's much
> faster than figuring the versions out by yourself.
>
> As long as we have simple way of managing it and document how to
> upgrade/downgrade dependencies in your own fork, and mention how to locally
> release Airflow as a package, I think your case could be covered even
> better than now. What do you think ?
>
> J.
>
> On Fri, Oct 5, 2018 at 2:34 PM EKC (Erik Cederstrand)
> <EKC@xxxxxxxxxxxxx.invalid> wrote:
>
> > For us, exact pinning of versions would be problematic. We have DAG code
> > that shares direct and indirect dependencies with Airflow, e.g. lxml,
> > requests, pyhive, future, thrift, tzlocal, psycopg2 and ldap3. If our DAG
> > code for some reason needs a newer point release due to a bug that's
> fixed,
> > then we can't cleanly build a virtual environment containing the fixed
> > version. For us, it's already a problem that Airflow has quite strict
> (and
> > sometimes old) requirements in setup.py.
> >
> > Erik
> > ________________________________
> > From: Jarek Potiuk <Jarek.Potiuk@xxxxxxxxxxx>
> > Sent: Friday, October 5, 2018 2:01:15 PM
> > To: dev@xxxxxxxxxxxxxxxxxxxxxxxxxxxx
> > Subject: Re: Pinning dependencies for Apache Airflow
> >
> > I think one solution to release approach is to check as part of automated
> > Travis build if all requirements are pinned with == (even the deep ones)
> > and fail the build in case they are not for ALL versions (including
> > dev). And of course we should document the approach of releases/upgrades
> > etc. If we do it all the time for development versions (which seems quite
> > doable), then transitively all the releases will also have pinned
> versions
> > and they will never try to upgrade any of the dependencies. In poetry
> > (similarly in pip-tools with .in file) it is done by having a .lock file
> > that specifies exact versions of each package so it can be rather easy to
> > manage (so it's worth trying it out I think  :D  - seems a bit more
> > friendly than pip-tools).
> >
> > There is a drawback - of course - with manually updating the module that
> > you want, but I really see that as an advantage rather than drawback
> > especially for users. This way you maintain the property that it will
> > always install and work the same way no matter if you installed it today
> or
> > two months ago. I think the biggest drawback for maintainers is that you
> > need some kind of monitoring of security vulnerabilities and cannot rely
> on
> > automated security upgrades. With >= requirements those security updates
> > might happen automatically without anyone noticing, but to be honest I
> > don't think such upgrades are guaranteed even in current setup for all
> > security issues for all libraries anyway.
> >
> > Finding the need to upgrade because of security issues can be quite
> > automated. Even now I noticed Github started to inform owners about
> > potential security vulnerabilities in used libraries for their project.
> > Those notifications can be sent to devlist and turned into JIRA issues
> > followed bvy  minor security-related releases (with only few library
> > dependencies upgraded).
> >
> > I think it's even easier to automate it if you have pinned dependencies -
> > because it's generally easy to find applicable vulnerabilities for
> specific
> > versions of libraries by static analysers - when you have >=, you never
> > know which version will be used until you actually perform the
> > installation.
> >
> > There is one big advantage for maintainers for "pinned" case. Your users
> > always have the same dependencies - so when issue is raised, you can
> > reproduce it more easily. It's hard to know which version user has (as
> the
> > user could install it month ago or yesterday) and even if you find out by
> > asking the user, you might not be able to reproduce the set of
> requirements
> > easily (simply because there are already newer versions of the libraries
> > released and they are used automatically). You can ask the user to run
> pip
> > --upgrade but that's dangerous and pretty lame ("check the latest
> version -
> > maybe it fixes your problem ? ") and sometimes not possible (e.g. someone
> > has pre-built docker image with dependencies from few months ago and
> cannot
> > rebuild the image easily).
> >
> > J.
> >
> > On Fri, Oct 5, 2018 at 12:35 PM Ash Berlin-Taylor <ash@xxxxxxxxxx>
> wrote:
> >
> > > One thing to point out here.
> > >
> > > Right now if you `pip install apache-airflow=1.10.0` in a clean
> > > environment it will fail.
> > >
> > > This is because we pin flask-login to 0.2.1 but flask-appbuilder is >=
> > > 1.11.1, so that pulls in 1.12.0 which requires flask-login >= 0.3.
> > >
> > > So I do think there is maybe something to be said about pinning for
> > > releases. The down side to that is that if there are updates to a
> module
> > > that we want then we have to make a point release to let people get it
> > >
> > > Both methods have draw-backs
> > >
> > > -ash
> > >
> > > > On 4 Oct 2018, at 17:13, Arthur Wiedmer <arthur.wiedmer@xxxxxxxxx>
> > > wrote:
> > > >
> > > > Hi Jarek,
> > > >
> > > > I will +1 the discussion Dan is referring to and George's advice.
> > > >
> > > > I just want to double check we are talking about pinning in
> > > > requirements.txt only.
> > > >
> > > > This offers the ability to
> > > > pip install -r requirements.txt
> > > > pip install --no-deps airflow
> > > > For a guaranteed install which works.
> > > >
> > > > Several different requirement files can be provided for specific use
> > > cases,
> > > > like a stable dev one for instance for people wanting to work on
> > > operators
> > > > and non-core functions.
> > > >
> > > > However, I think we should proactively test in CI against unpinned
> > > > dependencies (though it might be a separate case in the matrix) , so
> > that
> > > > we get advance warning if possible that things will break.
> > > > CI downtime is not a bad thing here, it actually caught a problem :)
> > > >
> > > > We should unpin as possible in setup.py to only maintain minimum
> > required
> > > > compatibility. The process of pinning in setup.py is extremely
> > > detrimental
> > > > when you have a large number of python libraries installed with
> > different
> > > > pinned versions.
> > > >
> > > > Best,
> > > > Arthur
> > > >
> > > > On Thu, Oct 4, 2018 at 8:36 AM Dan Davydov
> > <ddavydov@xxxxxxxxxxx.invalid
> > > >
> > > > wrote:
> > > >
> > > >> Relevant discussion about this:
> > > >>
> > > >>
> > >
> >
> https://emea01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgithub.com%2Fapache%2Fincubator-airflow%2Fpull%2F1809%23issuecomment-257502174&amp;data=01%7C01%7CEKC%40novozymes.com%7Cd31403917b084e3615c208d62aba4c24%7C43d5f49ee03a4d22a2285684196bb001%7C0&amp;sdata=MM%2FoNwkPYR8UtBUczXLfZD2lCp7Ig%2BI%2FL2rFszcoJi8%3D&amp;reserved=0
> > > >>
> > > >> On Thu, Oct 4, 2018 at 11:25 AM Jarek Potiuk <
> > Jarek.Potiuk@xxxxxxxxxxx>
> > > >> wrote:
> > > >>
> > > >>> TL;DR; A change is coming in the way how dependencies/requirements
> > are
> > > >>> specified for Apache Airflow - they will be fixed rather than
> > flexible
> > > >> (==
> > > >>> rather than >=).
> > > >>>
> > > >>> This is follow up after Slack discussion we had with Ash and Kaxil
> -
> > > >>> summarising what we propose we'll do.
> > > >>>
> > > >>> *Problem:*
> > > >>> During last few weeks we experienced quite a few downtimes of
> > TravisCI
> > > >>> builds (for all PRs/branches including master) as some of the
> > > transitive
> > > >>> dependencies were automatically upgraded. This because in a number
> of
> > > >>> dependencies we have  >= rather than == dependencies.
> > > >>>
> > > >>> Whenever there is a new release of such dependency, it might cause
> > > chain
> > > >>> reaction with upgrade of transitive dependencies which might get
> into
> > > >>> conflict.
> > > >>>
> > > >>> An example was Flask-AppBuilder vs flask-login transitive
> dependency
> > > with
> > > >>> click. They started to conflict once AppBuilder has released
> version
> > > >>> 1.12.0.
> > > >>>
> > > >>> *Diagnosis:*
> > > >>> Transitive dependencies with "flexible" versions (where >= is used
> > > >> instead
> > > >>> of ==) is a reason for "dependency hell". We will sooner or later
> hit
> > > >> other
> > > >>> cases where not fixed dependencies cause similar problems with
> other
> > > >>> transitive dependencies. We need to fix-pin them. This causes
> > problems
> > > >> for
> > > >>> both - released versions (cause they stop to work!) and for
> > development
> > > >>> (cause they break master builds in TravisCI and prevent people from
> > > >>> installing development environment from the scratch.
> > > >>>
> > > >>> *Solution:*
> > > >>>
> > > >>>   - Following the old-but-good post
> > > >>>
> >
> https://emea01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fnvie.com%2Fposts%2Fpin-your-packages%2F&amp;data=01%7C01%7CEKC%40novozymes.com%7Cd31403917b084e3615c208d62aba4c24%7C43d5f49ee03a4d22a2285684196bb001%7C0&amp;sdata=PVE3S4mgki7L%2BcAe104o2cf68wRXolvYXRFmAyiX8gA%3D&amp;reserved=0
> > we are going to fix the
> > > >>> pinned
> > > >>>   dependencies to specific versions (so basically all dependencies
> > are
> > > >>>   "fixed").
> > > >>>   - We will introduce mechanism to be able to upgrade dependencies
> > with
> > > >>>   pip-tools (
> >
> https://emea01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgithub.com%2Fjazzband%2Fpip-tools&amp;data=01%7C01%7CEKC%40novozymes.com%7Cd31403917b084e3615c208d62aba4c24%7C43d5f49ee03a4d22a2285684196bb001%7C0&amp;sdata=Kt9CjWrolvpjp7MwIR2nn8EIf9CW9HW02U7GVGyOXMo%3D&amp;reserved=0
> ).
> > We might also
> > > >> take a
> > > >>>   look at pipenv:
> >
> https://emea01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fpipenv.readthedocs.io%2Fen%2Flatest%2F&amp;data=01%7C01%7CEKC%40novozymes.com%7Cd31403917b084e3615c208d62aba4c24%7C43d5f49ee03a4d22a2285684196bb001%7C0&amp;sdata=1tiY6pgX3IbRYC5W0HKr0ER2qMZ3GKYrwmWg%2BUo0tqs%3D&amp;reserved=0
> > > >>>   - People who would like to upgrade some dependencies for their
> PRs
> > > >> will
> > > >>>   still be able to do it - but such upgrades will be in their PR
> thus
> > > >> they
> > > >>>   will go through TravisCI tests and they will also have to be
> > > specified
> > > >>> with
> > > >>>   pinned fixed versions (==). This should be part of review process
> > to
> > > >>> make
> > > >>>   sure new/changed requirements are pinned.
> > > >>>   - In release process there will be a point where an upgrade will
> be
> > > >>>   attempted for all requirements (using pip-tools) so that we are
> not
> > > >>> stuck
> > > >>>   with older releases. This will be in controlled PR environment
> > where
> > > >>> there
> > > >>>   will be time to fix all dependencies without impacting others and
> > > >> likely
> > > >>>   enough time to "vet" such changes (this can be done for
> alpha/beta
> > > >>> releases
> > > >>>   for example).
> > > >>>   - As a side effect dependencies specification will become far
> > simpler
> > > >>>   and straightforward.
> > > >>>
> > > >>> Happy to hear community comments to the proposal. I am happy to
> take
> > a
> > > >> lead
> > > >>> on that, open JIRA issue and implement if this is something
> community
> > > is
> > > >>> happy with.
> > > >>>
> > > >>> J.
> > > >>>
> > > >>> --
> > > >>>
> > > >>> *Jarek Potiuk, Principal Software Engineer*
> > > >>> Mobile: +48 660 796 129
> > > >>>
> > > >>
> > >
> > >
> >
> > --
> >
> > *Jarek Potiuk, Principal Software Engineer*
> > Mobile: +48 660 796 129
> >
>
>
> --
>
> *Jarek Potiuk, Principal Software Engineer*
> Mobile: +48 660 796 129
>