This will give us signal about the impact of ccache on the builds in the distribution tests. The code is copied from grpc#42033.

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Closes grpc#42077

COPYBARA_INTEGRATE_REVIEW=grpc#42077 from murgatroid99:distribtest_ccache_stats ba85091
PiperOrigin-RevId: 902675367

…try to ccache download (grpc#42180)

### Description

Fix flaky tests for the log, looks like a network issue.

```
#18 [15/18] RUN curl -sSL -o ccache.tar.gz https://github.com/ccache/ccache/releases/download/v4.11.3/ccache-4.11.3.tar.gz     && tar -zxf ccache.tar.gz     && cd ccache-4.11.3     && mkdir build && cd build     && cmake -DCMAKE_BUILD_TYPE=Release -DZSTD_FROM_INTERNET=ON -DHIREDIS_FROM_INTERNET=ON ..     && make -j4 && make install     && cd ../..     && rm -rf ccache-4.11.3 ccache.tar.gz
#18 11.37
#18 11.37 gzip: stdin: not in gzip format
#18 11.37 tar: Child returned status 1
#18 11.37 tar: Error is not recoverable: exiting now
#18 ERROR: process "/bin/sh -c curl -sSL -o ccache.tar.gz https://github.com/ccache/ccache/releases/download/v4.11.3/ccache-4.11.3.tar.gz     && tar -zxf ccache.tar.gz     && cd ccache-4.11.3     && mkdir build && cd build     && cmake -DCMAKE_BUILD_TYPE=Release -DZSTD_FROM_INTERNET=ON -DHIREDIS_FROM_INTERNET=ON ..     && make -j4 && make install     && cd ../..     && rm -rf ccache-4.11.3 ccache.tar.gz" did not complete successfully: exit code: 2
------
```

Added retry to ccache install.

Closes grpc#42180

COPYBARA_INTEGRATE_REVIEW=grpc#42180 from asheshvidyut:fixit/fix-flake 33a66ed
PiperOrigin-RevId: 902683742

…pc#42150)

We enabled EventEngine for Python in the 1.80 release, making that the first time that any of these experiments were fully rolled out in open source. We plan to monitor for user issues for two full releases and then start removing the experiments. The new end date is the approximate target date for when we will do that.

Closes grpc#42150

COPYBARA_INTEGRATE_REVIEW=grpc#42150 from murgatroid99:extend_event_engine_experiments 72d2c0b
PiperOrigin-RevId: 902687984

Previously ccache wasn't properly enabled for our python builds before because setuptools has special logic to find MSVC and disregard `CC/CXX` flags https://github.com/pypa/setuptools/blob/main/setuptools/msvc.py. There's no graceful solution other than monkeypatching (which we already do with `_spawn_patch.py`).

Certain MSVC flags are not properly handled by ccache 4.8 so we need to rewrite and exclude them from hash key generation.

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Closes grpc#42171

COPYBARA_INTEGRATE_REVIEW=grpc#42171 from yuanweiz:fixit-windows-ccache 5ff00ca
PiperOrigin-RevId: 902859436

The only github.com links in `build_autogenerated.yaml` are the ones that correspond to packages that `CMakeLists.txt` downloads, so we mirror those links in GCS the same way we do bazel dependencies. The goal is to use this mirror as an alternative download target in CMake to minimize flakes from having our downloads throttled by GitHub.

I also switched from `gsutil` to `gcloud storage` because `gsutil` wasn't working for me and the command line output recommended switching.

Closes grpc#42172

COPYBARA_INTEGRATE_REVIEW=grpc#42172 from murgatroid99:cmake_deps_mirror 63468be
PiperOrigin-RevId: 903662332

…dows version bump) (grpc#42195)

In the Python Windows builds, ccache currently has a low cache hit rate and fails to populate the direct mode cache. This is an attempt to fix that.

Closes grpc#42195

COPYBARA_INTEGRATE_REVIEW=grpc#42195 from murgatroid99:python_windows_ccache_fix 2205915
PiperOrigin-RevId: 903665805

…7.x (grpc#41948)

### Description

Remove upper bound from `grpc-status` `setup.py` install requirement for
protobuf.

Fixes grpc#41933 

### Testing

`cd grpc && bash test.sh`

```bash
VENV_NAME=".venv_status_pb_test"
python3 -m venv "$VENV_NAME"
source "$VENV_NAME/bin/activate"
pip install -U "protobuf>=7.0.0"
pip install -U googleapis-common-protos coverage
pip install -e .
cd src/python/grpcio_status
pip install --no-deps -e .
cd ../../..
export PYTHONPATH=$(pwd)/src/python/grpcio_tests:$(pwd)/src/python/grpcio_status
python3 -m unittest tests.status._grpc_status_test
python3 -m unittest tests_aio.status.grpc_status_test
deactivate
```

---------

Co-authored-by: Sergii Tkachenko <sergiitk@google.com>
Co-authored-by: gemini-code-assist[bot] <176961590+gemini-code-assist[bot]@users.noreply.github.com>

…2198)

cmake/build/round_robin_test --gtest_filter=RoundRobinTest.StartsConnectingFromRandomIndex

Root Cause: we have 3 index 0,1, 2 and we query to get starting index. We expect to get a random index, so test assert we get something other than 0. the probability is 1/3 we do this 10 times , so failure probability becomes (1/3)^10 approx 0.0017%  . That is the reason we have not seen many instance of this failure.

Increasing the loop count to 30. (This will not increase test time as we will return early as soon as we get index other than 0). This will have failure probability (1/3)^30 ~ 10^ -15 (almost impossible)

Closes grpc#42198

COPYBARA_INTEGRATE_REVIEW=grpc#42198 from pawbhard:rr_flake 9a71e0b
PiperOrigin-RevId: 903699099

Closes grpc#42201

COPYBARA_INTEGRATE_REVIEW=grpc#42201 from rishesh007:p_fix d410156
PiperOrigin-RevId: 903774639

… build directory consistent across runs) (grpc#42212)

We see ccache cache misses because each python build runs in a different temporary directory, and some header file names in the cache entry's manifest appear to use the full file path, so they fail to match. This change resolves that by making the build directory consistent for each build type.

ref:
- b/501458064
- Previous change: grpc#42195

Closes grpc#42212

COPYBARA_INTEGRATE_REVIEW=grpc#42212 from murgatroid99:python_windows_ccache_basedir a29d1bb
PiperOrigin-RevId: 904139620