> However, this doesn't help with the newly added tests that introduce
flakiness. For this, we need some way
to detect when a new test has been added. Still thinking through this...
Maybe we can use git + gradle develocity to address it.
1) list the files changed recently (for example: git diff --name-only "@{7
days ago}")
2) use the test-related filename to query Gradle Develocity with "7 days
ago"
3) the test cases having fewer builds are viewed as "new tests"
WDYT?
David Arthur <mum...@gmail.com> 於 2024年9月19日 週四 下午11:56寫道：
> TengYao,
>
> > These two mechanisms are independent. We could manually remove a tag from
> a
> test, but at the same time, it might still be quarantined.
> I know the above situation might sound weird, but I just want to understand
> how it would work.
>
> If we remove a tag from a test, we are signaling that we *think* it is now
> stable. However, until we have data
> to prove that, we can run the test in the quarantine. This helps with the
> situation where there are multiple
> sources of flakiness and we are making iterative progress on improving it.
>
> The alternative is to keep the fix in a PR until the developer gets enough
> signal from the PR builds to be
> convinced that the flakiness is gone. I mention in the KIP that this
> approach has issues.
>
>
> Chia-Ping,
>
> > If so, could we query the Gradle develocity to get flaky and then make
> only those flaky
> retryable in CI?
>
> This can work for existing flaky tests. We can query Develocity to find
> flaky tests in the last N days
> and run only those tests with retry. This is what I meant by "data driven"
> for the quarantine. So, no need to track
> "quarantined.txt" file separately -- we can derive this data at build time
> from Develocity.
>
> However, this doesn't help with the newly added tests that introduce
> flakiness. For this, we need some way
> to detect when a new test has been added. Still thinking through this...
>
> -David
>
> On Thu, Sep 19, 2024 at 11:33 AM Chia-Ping Tsai <chia7...@gmail.com>
> wrote:
>
> > hi David
> >
> > The two-tiered approach is interesting and I have questions similar to
> > TengYao.
> >
> > BUT, go back to the usage of quarantine and isolation. It seems to me
> they
> > are used to make our CI not be noised by the flaky, right? If so, could
> we
> > query the Gradle develocity to get flaky and then make only those flaky
> > retryable in CI? That means a non-flaky (stable) test must pass without
> > retry.
> >
> > This approach is more simple (I guess), and it can isolate the flaky (by
> > retry) from CI. If a flaky can't pass after retry, I feel it is a
> critical
> > failed test rather than just a flaky. On top of that, this approach does
> > not need an extra file ("quarantined.txt") in git control and it does not
> > need to change any code of test classes.
> >
> > Best,
> > Chia-Ping
> >
> > TengYao Chi <kiting...@gmail.com> 於 2024年9月19日 週四 下午11:19寫道：
> >
> > > Hi David,
> > >
> > > Thanks for the explanation.
> > >
> > > I like this two-tiered approach, which gives us more flexibility to
> > handle
> > > flaky tests.
> > >
> > > The following is my understanding of how it works; please correct me if
> > I'm
> > > wrong:
> > > If we adopt the two-tiered approach, the test might have two
> > > states.(Isolated by developer, Quarantined automatically).
> > > These two mechanisms are independent. We could manually remove a tag
> > from a
> > > test, but at the same time, it might still be quarantined.
> > > I know the above situation might sound weird, but I just want to
> > understand
> > > how it would work.
> > >
> > > Best Regards,
> > > TengYao
> > >
> > > David Arthur <mum...@gmail.com> 於 2024年9月19日 週四 下午10:07寫道：
> > >
> > > > Chia/TengYao/TaiJuWu, I agree that tags are a straightforward
> approach.
> > > In
> > > > fact, my initial idea was to use tags as the isolation mechanism.
> > > >
> > > > Let me try to motivate the use of a text file a bit more.
> > > >
> > > > Consider the "new tests" scenario where a developer has added a new
> > > > integration test. If we use annotations, this means someone (the
> > original
> > > > developer, or another committer) will need to raise a PR after a few
> > days
> > > > to remove the annotation (assuming the test was stable). Eventually,
> I
> > > was
> > > > hoping to automate or partially automate this aspect of the system.
> It
> > > > seems simpler to write a script that modifies a plain text file
> > compared
> > > > with removing annotations in Java code.
> > > >
> > > > > we don't need to worry that "quarantined.txt" having out-of-date
> test
> > > > names
> > > >
> > > > This could be a problem, yes.
> > > >
> > > > ---
> > > >
> > > > Maybe we can consider a two-tiered approach here:
> > > >
> > > > Isolation (manual)
> > > > * Test is marked with tag annotation
> > > > * This is a permanent state until the developers think the test is
> > > healthy
> > > > again
> > > > * These tests are run in a separate build step to not affect build
> > > > outcomes, but gather data
> > > >
> > > >
> > > > Quarantine (automated)
> > > > * Tests leaving Isolation enter the Quarantine automatically
> > > > * New integration tests enter the Quarantine automatically
> > > > * Test stays in quarantine for a few days to evaluate
> > > > * These tests are run in a separate build step to not affect build
> > > > outcomes, but gather data
> > > > * If all runs are passing, it leaves the quarantine
> > > >
> > > > I think with this approach, we can make the Quarantine fully
> > data-driven
> > > > and automated. Essentially, the build will query Develocity for flaky
> > > test
> > > > results from the last N days and run those tests separately.
> > > >
> > > >
> > > > WDYT?
> > > >
> > > > On Thu, Sep 19, 2024 at 12:49 AM 吳岱儒 <tjwu1...@gmail.com> wrote:
> > > >
> > > > > Hi David,
> > > > >
> > > > > Thank you for KIP.
> > > > >
> > > > > Could we include percentages for each flaky test in
> quarantined.txt?
> > > This
> > > > > would help us prioritize which tests to resolve first.
> > > > >
> > > > > Additionally, I would prefer to add a flaky (JUnit) tag to the
> source
> > > > code
> > > > > so we can focus on these tests during development.
> > > > >
> > > > > Thanks,
> > > > > TaiJuWu
> > > > >
> > > > >
> > > > > On Thu, Sep 19, 2024 at 11:51 AM TengYao Chi <kiting...@gmail.com>
> > > > wrote:
> > > > >
> > > > > > Hi David,
> > > > > >
> > > > > > Thanks for this great KIP.
> > > > > >
> > > > > > I really appreciate the goal of this KIP, which aims to stabilize
> > the
> > > > > build
> > > > > > and improve our confidence in CI results.
> > > > > > It addresses a real issue where we've become accustomed to seeing
> > > > failed
> > > > > > results from CI, and this is definitely not good for the Kafka
> > > > community.
> > > > > >
> > > > > > I have a question regarding this KIP:
> > > > > > It seems that we need to maintain the `quarantined.txt` files
> > > manually,
> > > > > is
> > > > > > that correct?
> > > > > > I'm thinking this could become an issue, especially with the
> > planned
> > > > > > removal of ZK in 4.0, which will undoubtedly bring many changes
> to
> > > our
> > > > > > codebase.
> > > > > > Given that, maintaining the `quarantined.txt` files might become
> a
> > > > pain.
> > > > > > It would be nice if we could maintain it programmatically.
> > > > > >
> > > > > > Best Regards,
> > > > > > TengYao
> > > > > >
> > > > > > Chia-Ping Tsai <chia7...@gmail.com> 於 2024年9月19日 週四 上午3:24寫道：
> > > > > >
> > > > > > > hi David
> > > > > > >
> > > > > > > The KIP is beautiful and I do love a rule which makes us handle
> > > those
> > > > > > flaky
> > > > > > > seriously.
> > > > > > >
> > > > > > > Regarding the "JUnit Tags", it can bring some benefits to us.
> > > > > > >
> > > > > > > 1. we can retry only the tests having "flaky" annotation. Other
> > > > > non-flaky
> > > > > > > tests should not be retryable
> > > > > > > 2. we don't need to worry that "quarantined.txt" having
> > out-of-date
> > > > > test
> > > > > > > names
> > > > > > > 3. we can require the flaky annotation must have jira link.
> That
> > > > means
> > > > > > the
> > > > > > > PR's author must create the jira link for the new flaky
> > > > > > >
> > > > > > > Also, we can add a gradle task to generate "quarantined.txt"
> file
> > > if
> > > > > > needs.
> > > > > > >
> > > > > > > Best,
> > > > > > > Chia-Ping
> > > > > > >
> > > > > > > David Arthur <mum...@gmail.com> 於 2024年9月19日 週四 上午12:02寫道：
> > > > > > >
> > > > > > > > Hello, Kafka community!
> > > > > > > >
> > > > > > > > Looking at the last 7 days of GitHub, we have 59 out of 64
> > trunk
> > > > > builds
> > > > > > > > having flaky tests. Excluding timeouts (a separate issue),
> > only 4
> > > > > > builds
> > > > > > > > out of the last 7 days have failed due to excess test
> failures.
> > > > This
> > > > > is
> > > > > > > > actually a slight improvement when compared with the last 28
> > > days.
> > > > > But
> > > > > > > > still, this is obviously a bad situation to be in.
> > > > > > > >
> > > > > > > > We have previously discussed a few ideas to mitigate the
> impact
> > > > that
> > > > > > > flaky
> > > > > > > > tests have on our builds. For PRs, we are actually seeing a
> lot
> > > of
> > > > > > > > successful status checks due to our use of the Develocity
> test
> > > > retry
> > > > > > > > feature. However, the blanket use of "testRetry" is a bad
> > > practice
> > > > in
> > > > > > > > my opinion. It makes it far too easy for us to ignore tests
> > that
> > > > are
> > > > > > only
> > > > > > > > occasionally flaky. It also applies to unit tests which
> should
> > > > never
> > > > > be
> > > > > > > > flaky.
> > > > > > > >
> > > > > > > > Another problem is that we are naturally introducing flaky
> > tests
> > > as
> > > > > new
> > > > > > > > features (and tests) are introduced. Similar to feature
> > > > development,
> > > > > it
> > > > > > > > takes some time for tests to mature and stabilize -- tests
> are
> > > > code,
> > > > > > > after
> > > > > > > > all.
> > > > > > > >
> > > > > > > > I have written down a proposal for tracking and managing our
> > > flaky
> > > > > > > tests. I
> > > > > > > > have written this as a KIP even though this is an internal
> > > change.
> > > > I
> > > > > > did
> > > > > > > so
> > > > > > > > because I would like us to discuss, debate, and solidify a
> plan
> > > --
> > > > > and
> > > > > > > > ultimately vote on it. A KIP seemed like a good fit.
> > > > > > > >
> > > > > > > >
> > > > > > > >
> > > > > > >
> > > > > >
> > > > >
> > > >
> > >
> >
> https://cwiki.apache.org/confluence/display/KAFKA/KIP-1090+Flaky+Test+Management
> > > > > > > >
> > > > > > > > I have back-tested this strategy (as best as I can) to our
> > trunk
> > > > > builds
> > > > > > > > from the last month using data from Develocity (i.e.,
> > > > ge.apache.org
> > > > > ).
> > > > > > I
> > > > > > > > looked at two scenarios. The first scenario was simply
> > > quarantining
> > > > > > tests
> > > > > > > > with higher than 1% flaky failures, no test re-runs were
> > > > considered.
> > > > > > The
> > > > > > > > second scenario extends the first by allowing up to 3 total
> > flaky
> > > > > > > failures
> > > > > > > > from non-quarantined tests (tests with less than 1% total
> > > > flakiness).
> > > > > > > >
> > > > > > > > Total builds: *238*
> > > > > > > > Flaky/Failed builds: *228*
> > > > > > > > Flaky builds scenario 1 (quarantine only): *40*
> > > > > > > > Flaky builds scenario 2 (quarantine + retry): *3*
> > > > > > > >
> > > > > > > > In other words, we can tackle the worst flaky failures with
> the
> > > > > > > quarantine
> > > > > > > > strategy as described in the KIP and handle the long tail of
> > > flaky
> > > > > > > failures
> > > > > > > > with the Develocity retry plugin. If we only had 3 failing
> > trunk
> > > > > builds
> > > > > > > per
> > > > > > > > month to investigate, I'd say we were in pretty good shape :)
> > > > > > > >
> > > > > > > > Let me know what you think!
> > > > > > > >
> > > > > > > > Cheers,
> > > > > > > > David A
> > > > > > > >
> > > > > > >
> > > > > >
> > > > >
> > > >
> > > >
> > > > --
> > > > David Arthur
> > > >
> > >
> >
>
>
> --
> David Arthur
>
