There was a ~1% flake in grpclb end2end tests that was reproducible in opt builds, manifesting as a hang, usually in a the SingleBalancerTest.Fallback test. Through experimentation, I found that by skipping the death test in the grpclb end2end test suite, the hang was no longer reproducible in 10,000 runs. Similarly, moving this test to the end of the suite, or making it run first (as is the case in this PR) resulted in 0 failures in 3000 runs.
It's unclear to me yet why the death test causes things to be unstable in this way. It's clear from the logs that one test does affect the rest, grpc_init is done once for all tests, so all tests utilize the same EventEngine ... until the death test completes, and a new EventEngine is created for the next test.
I think this death test is sufficiently artificial that it's fine to change the test ordering itself, and ignore the wonky intermediate state that results from it.
Reproducing the flake:
```
tools/bazel --bazelrc=tools/remote_build/linux.bazelrc test \
-c opt \
--test_env=GRPC_TRACE=event_engine \
--runs_per_test=5000 \
--test_output=summary \
test/cpp/end2end/grpclb_end2end_test@poller=epoll1
```
* WRR: port StaticStrideScheduler to OSS
* WIP
* Automated change: Fix sanity tests
* fix build
* remove unused aliases
* fix another type mismatch
* remove unnecessary include
* move benchmarks to their own file, and don't run it on windows
* Automated change: Fix sanity tests
* add OOB reporting
* generate_projects
* clang-format
* add config parser test
* clang-tidy and minimize lock contention
* add config defaults
* add oob_reporting_period config field and add basic test
* Automated change: Fix sanity tests
* fix test
* change test to use basic RR
* WIP: started exposing peer address to LB policy API
* first WRR test passing!
* small cleanup
* port RR fix to WRR
* test helper refactoring
* more test helper refactoring
* WIP: trying to fix test to have the right weights
* more WIP -- need to make pickers DualRefCounted
* fix timer ref handling and get tests working
* clang-format
* iwyu and generate_projects
* fix build
* add test for OOB reporting
* keep only READY subchannels in the picker
* add file missed in a previous commit
* fix sanity
* iwyu
* add weight expiration period
* add tests for weight update period and OOB reporting period
* Automated change: Fix sanity tests
* lower bound for timer interval
* consistently apply grpc_test_slowdown_factor()
* cache time in test
* add blackout_period tests
* avoid some unnecessary copies
* clang-format
* add field to config test
* simplify orca watcher tracking
* attempt to fix build
* iwyu
* generate_projects
* update xds proto dependency
* add xDS LB policy entry to registry
* add "_experimental" suffix to policy name
* update LB policy name and remove debug log
* add env var protection
* generate_projects
* gen_upb_api
* WRR: update tests to cover qps plumbing
* WIP
* Automated change: Fix sanity tests
* more WIP
* basic WRR e2e test working
* add OOB test
* add xDS WRR e2e test
* clang-format
* fix sanity
* ignore duplicate addresses
* Automated change: Fix sanity tests
* add new tracer to doc/environment_variables.md
* retain scheduler state across pickers
* Automated change: Fix sanity tests
* use separate mutexes for scheduler and timer
* sort addresses to avoid index churn
* remove fetch_sub for wrap around in RR case
Co-authored-by: markdroth <markdroth@users.noreply.github.com>
* WRR: port StaticStrideScheduler to OSS
* WIP
* Automated change: Fix sanity tests
* fix build
* remove unused aliases
* fix another type mismatch
* remove unnecessary include
* move benchmarks to their own file, and don't run it on windows
* Automated change: Fix sanity tests
* add OOB reporting
* generate_projects
* clang-format
* add config parser test
* clang-tidy and minimize lock contention
* add config defaults
* add oob_reporting_period config field and add basic test
* Automated change: Fix sanity tests
* fix test
* change test to use basic RR
* WIP: started exposing peer address to LB policy API
* first WRR test passing!
* small cleanup
* port RR fix to WRR
* test helper refactoring
* more test helper refactoring
* WIP: trying to fix test to have the right weights
* more WIP -- need to make pickers DualRefCounted
* fix timer ref handling and get tests working
* clang-format
* iwyu and generate_projects
* fix build
* add test for OOB reporting
* keep only READY subchannels in the picker
* add file missed in a previous commit
* fix sanity
* iwyu
* add weight expiration period
* add tests for weight update period and OOB reporting period
* Automated change: Fix sanity tests
* lower bound for timer interval
* consistently apply grpc_test_slowdown_factor()
* cache time in test
* add blackout_period tests
* avoid some unnecessary copies
* clang-format
* add field to config test
* simplify orca watcher tracking
* attempt to fix build
* iwyu
* generate_projects
* add "_experimental" suffix to policy name
* WRR: update tests to cover qps plumbing
* WIP
* more WIP
* basic WRR e2e test working
* add OOB test
* fix sanity
* ignore duplicate addresses
* Automated change: Fix sanity tests
* add new tracer to doc/environment_variables.md
* retain scheduler state across pickers
* Automated change: Fix sanity tests
* use separate mutexes for scheduler and timer
* sort addresses to avoid index churn
* remove fetch_sub for wrap around in RR case
Co-authored-by: markdroth <markdroth@users.noreply.github.com>
* Revert "Revert "xDS stateful session affinity: add config plumbing (#31827)" (#31873)"
This reverts commit 4f15d3dcf9.
* fix build for compilers too dumb to recognize the full set of enum values
* Revert "Revert "xDS RouteConfig: use ValidationErrors and add unit test (#31418)" (#31653)"
This reverts commit 335b74fea7.
* use auto instead of explicitly naming the protobuf map type
Specific changes:
- Use absl::variant<> for HashPolicy types.
- Pull validation of resulting LB policy configs out of ClusterSpecifierPlugin registry and into RouteConfig validation.
- Don't ignore missing Any fields in HTTP filter configs if is_optional is true, since is_optional should apply only to unsupported filter types, not to malformed resource protos.
- Use ExtractXdsExtension() for HttpConnectionManager config itself.
- Minor API improvements to StatusCodeSet to make it a bit more useful in tests.
- Changed StringMatcher to return the underlying error message when a regex fails to compile.
- Fix a bug whereby a ClusterSpecifierPlugin would not be returned if it was not used in a vhost, even if it was used in another vhost.
* Revert "Revert "xDS Listener: use ValidationErrors and add unit test (#31351)" (#31456)"
This reverts commit ab3d62ae8f.
* Revert "Revert "xds_http_filters_test: fix includes for import (#31454)" (#31455)"
This reverts commit 32590d110a.
* fix import
* work around internal differences in Any API (string vs. cord)
* iwyu
Eugene Ostroukhov
AJ Heller
Xuan Wang
Yousuk Seung
Craig Tiller
Mark D. Roth
Alisha Nanda
Yash Tibrewal
Vignesh Babu
Yijie Ma
Cheng-Yu Chung
Richard Belleville
Eryu Xia
Hannah Shi
Esun Kim