[
https://issues.apache.org/jira/browse/CASSANDRA-14134?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16314011#comment-16314011
]
Ariel Weisberg commented on CASSANDRA-14134:
--------------------------------------------
Linking to the github diff seems broken right now. So I will have to specify
files and line numbers.
* One thing I noticed is that it seems like it's a bit easier for the harness
to orphan a running cluster? I know that with the nosetest setup I generally
never had to worry about leaving a C* cluster behind (which is pretty
shocking), but when I killed a running test today it left behind the cluster.
* cdc_test.py line 350 is part of a broken test you added a skip annotation to.
It looks like you added some whitelisting for log output, but that didn't fix
the test. Should we remove the whitelisting since it's not the right fix for
the test?
* commitlog_test.py line 444, why do you have to use that idiom to update the
list? List appending is still in python 3? Is this to avoid the not defined
check?
* Can you elaborate on why you had to switch to opening files in binary mode?
Was it a bug originally? Looks like those files are indeed binary. I am just
wondering if it manifested differently in python 3.
* dtest.py:176, comment is out of date? Fault handler is always on now?
* dtest.py has a few commented out bits of code that eventually probably need
to be deleted
* materialized view tests line 2390 you switch from threads to processes and
added a join? What were you trying to address by switching from processes to
threads, and adding the joins and timeouts? Was it hanging?
* I see cases in asserts where constant integers were changed from say 7L to
just 7. Is that intentional? What is that about? (materialized view test,
paging test)
* paxos_tests, you removed the utf-8 encoding statement at the top? Was that
doing anything? This happens in several files.
* read_repair_test is now inlining a method manually? test_read_repair? Do we
have to have that duplication? I know this Beobal's commit so I'll probably
have to come back to it.
* incremental_repair_test:176, it's using the Latin-1 encoding?
* base_replace_address_test failed to properly handshake peer, is this just
another case of this error is generated and it's fine? Seems like you add this
to tests that use JMX. Maybe using JMX should automatically cause this to be
added to ignored log lines?
* run_dtest.py still does the fork to a separate process. Does that accomplish
anything? Can we remove it?
* snapshot_test assert_directory_not_empty, I looked at this twice, it's just a
little too confusing and needs a comment as to what the parameters are and how
it works.
* You regenerated the thrift bindings to get a python 3 supported version? You
removed pycassa but it also looks like we were hardly using it? Just want to
make sure I understand what happened.
* tools/assertions.py assert_lists_equal_ignoring_order, this seems to sort
results coming from the DB. Shouldn't the DB already be providing a consistent
sort order for results? I thought that was well defined. I am wondering if we
are papering over result ordering issues in the DB.
I am going to look at read_repair_test now as it was a pretty significant
change and I don't know exactly what went down there.
> Migrate dtests to use pytest and python3
> ----------------------------------------
>
> Key: CASSANDRA-14134
> URL: https://issues.apache.org/jira/browse/CASSANDRA-14134
> Project: Cassandra
> Issue Type: Improvement
> Components: Testing
> Reporter: Michael Kjellman
> Assignee: Michael Kjellman
>
> h4. Get the C* dtests running on the pytest framework.
> C* DTests currently run using the python test framework nosetest. This
> framework has been largely abandoned with no releases since 2015 and a
> general strong consensus in the python community that pytest is the future.
> h4. Why should we do this.
> Currently (and historically) dtests have always been difficult to run, flaky
> and unpredictable in CI environments, and almost impossible to debug.
> On November 28th, 2017, I proposed on the dev@ list that we move the dtests
> from nosetests to pytests. I got replies from Jon Haddad, Philip Thompson,
> and kurt greaves with really only "+1" like replies to the proposal.
> Since then I've been working pretty much non stop to complete the large
> refactor of dtests to pytests. As part of this effort (and due to the
> migration tools that exist require it) I also ported the code to python3
> (from the current python 2.7 based code-base).
> h4. High-level summary of key changes, improvements, and new features.
> * Migrate dtests from executing using the nosetest framework to pytest
> * Port the entire code base from Python 2.7 to Python 3.6
> * Update run_dtests.py to work with pytest
> * Add --dtest-print-tests-only option to run_dtests.py to get easily parsable
> list of all available collected tests
> * Update README.md for executing the dtests with pytest
> * Add new debugging tips section to README.md to help with some basics of
> debugging python3 and pytest
> * Migrate all existing Enviornment Variable usage as a means to control dtest
> operation modes to argparse command line options with documented help on each
> toggles intended usage
> * Migration of old unitTest and nose based test structure to modern pytest
> fixture approach
> * Automatic detection of physical system resources to automatically determine
> if @pytest.mark.resource_intensive annotated tests should be collected and
> run on the system where they are being executed
> * new pytest fixture replacements for @since and @pytest.mark.upgrade_test
> annotations
> * Migration to python logging framework
> * Upgrade thrift bindings to latest version with full python3 compatibility
> * Remove deprecated cql and pycassa dependencies and migrate any remaining
> tests to fully remove those dependencies
> * Fixed dozens of tests that would hang the pytest framework forever when run
> in CI enviornments
> * Ran code nearly 300 times in CircleCI during the migration and to find,
> identify, and fix any tests capable of hanging CI
> * Upgrade Tests do not yet run in CI and still need additional migration work
> (although all upgrade test classes compile successfully)
> I started with the *nose2pytest* [https://github.com/pytest-dev/nose2pytest]
> migration tool. As this required python 3 language support I found myself
> down the 2to3 python migration path. While painful to do this, the benefits
> of python3 over python2.7 are numerous and moving to python3 for the
> additional debugging tools now available to use when fixing dtests makes the
> effort worth it for that reason alone!
> After the automated tools did their thing I began what was a much longer and
> tedious manual process than I ever could have expected due to the custom many
> ways we did things in dtests (frequently to work around nosetest limitations
> of missing features that thankfully are now all included with the pytest
> framework). I've done nearly 300 test runs of my migration branch with
> circleci.
> The latest CircleCI runs can be found at:
> (dtests without vnodes) [https://circleci.com/gh/mkjellman/cassandra/277]
> (dtests with vnodes) [https://circleci.com/gh/mkjellman/cassandra/278]
> With vnodes, there are currently only 6 remaining dtest test failures.
> Without vnodes, there are 12 remaining dtest failures.
> It turns out that after the dtests were moved to ASF Jenkins from cassci, the
> jobs were misconfigured and we actually haven't been running the dtests in
> the non-vnodes configuration. The current most recent trunk dtest job to
> complete on ASF Jenkins (with vnodes) was
> [https://builds.apache.org/view/A-D/view/Cassandra/job/Cassandra-trunk-dtest/387/].
> That test run had 36 test failures.
> There are great performance improvements so far with pytests. With a
> parallism factor of 90x in CircleCI the dtests-no-vnodes job completed all
> tests in 16 minutes and 24 seconds and the dtests-with-vnodes job completed
> all tests in 14 minutes and 22 seconds.. (Compare that to the 8+ hours ASF
> Jenkins currently takes!).
> A dtest on pytest compatible CircleCI configuration is available at
> https://github.com/mkjellman/cassandra/blob/trunk_circle/.circleci/config.yml
> A very small patch is required to ccm for 2 places that were not yet python3
> compatible. (I didn't do a full audit of ccm, but these appear to be the only
> two issues I've found even with a ton of testing when using ccmlib with
> dtests and running with python 3).
> {code}
> --- /home/cassandra/env/src/ccm/ccmlib/node.py 2017-12-13 03:11:13.000000000
> +0000-8").splitlines()))
> +++ node.py 2017-12-19 09:51:49.083186951 +0000
> @@ -57,10 +57,16 @@
> message = "Subprocess {} exited with non-zero status; exit status:
> {}".format(command, exit_status)
> if stdout:
> message += "; \nstdout: "
> - message += stdout
> + if isinstance(stdout, str):
> + message += stdout
> + else:
> + message += stdout.decode("utf-8")
> if stderr:
> message += "; \nstderr: "
> - message += stderr
> + if isinstance(stderr, str):
> + message += stderr
> + else:
> + message += stderr.decode("utf-8")
>
> Exception.__init__(self, message)
>
> @@ -2009,7 +2015,10 @@
>
> out, _, _ = handle_external_tool_process(p, ["sstableutil",
> '--type', 'final', ks, table])
>
> - return sorted(filter(lambda s: s.endswith('-Data.db'),
> out.splitlines()))
> + if isinstance(out, str):
> + return sorted(filter(lambda s: s.endswith('-Data.db'),
> out.splitlines()))
> + else:
> + return sorted(filter(lambda s: s.endswith('-Data.db'),
> out.decode("utf-8").splitlines()))
>
> def _get_load_from_info_output(info):
> {code}
> For the actual dtest work itself: I've squashed all my work down into a
> single commit available at
> [https://github.com/mkjellman/cassandra-dtest/tree/dtests_on_pytest_v2]
> And the actual commit available at
> [https://github.com/mkjellman/cassandra-dtest/commit/11201c149d1198c0d6d1a479e08bfb8695f14c9e]
> I tried to put a lot of effort into making the end user experience better for
> both bootstrapping and running dtests for the first time, but also day to
> day. I hope people like the approach! In addition to moving to argparse with
> commented command line arguments to control execution, I also updated the
> README.md to reflect the new pytest world and also added a new section with a
> few tips I learned while I was debugging hundreds of tests during this
> migration process that hopefully are helpful to the rest of the community
> going forward!
> I'm sure the first commit above isn't 100% perfect (although I really have
> put a lot of effort into it) but my one request is to hopefully get consensus
> with this first revision of changes committed to reduce any chance of further
> drift with the codebase as changes are committed into master.
--
This message was sent by Atlassian JIRA
(v6.4.14#64029)
---------------------------------------------------------------------
To unsubscribe, e-mail: [email protected]
For additional commands, e-mail: [email protected]
