Locust monkey patching leads to test cross-talking

[mreso]

🐛 Describe the bug

Some fail tests fail if locust is imported in test_benchmark.py

Error logs

>               self.pid = _posixsubprocess.fork_exec(
                        args, executable_list,
                        close_fds, tuple(sorted(map(int, fds_to_keep))),
                        cwd, env_list,
                        p2cread, p2cwrite, c2pread, c2pwrite,
                        errread, errwrite,
                        errpipe_read, errpipe_write,
                        restore_signals, start_new_session,
                        gid, gids, uid, umask,
                        preexec_fn)
E                       AttributeError: 'NoneType' object has no attribute 'fork_exec'

/home/ubuntu/miniconda3/envs/serve/lib/python3.10/subprocess.py:1796: AttributeError
----------------------------------------------------------------------------------------------------- Captured stdout setup -----------------------------------------------------------------------------------------------------
TorchServe is not currently running.
TorchServe is not currently running.
['torchserve', '--start', '--model-store', '/tmp/pytest-of-ubuntu/pytest-20/work_dir0/model_store', '--ts-config', '/tmp/pytest-of-ubuntu/pytest-20/tp_model0/config.properties', '--no-config-snapshots', '--disable-token', '--
model-api-enabled']
======================================================================================================= warnings summary ========================================================================================================
../miniconda3/envs/serve/lib/python3.10/site-packages/locust/__init__.py:15
  /home/ubuntu/miniconda3/envs/serve/lib/python3.10/site-packages/locust/__init__.py:15: MonkeyPatchWarning: Monkey-patching ssl after ssl has already been imported may lead to errors, including RecursionError on Python 3.6.
It may also silently lead to incorrect behaviour on Python 3.7. Please monkey-patch earlier. See https://github.com/gevent/gevent/issues/1016. Modules that had direct imports (NOT patched): ['urllib3.util.ssl_ (/home/ubuntu/m
iniconda3/envs/serve/lib/python3.10/site-packages/urllib3/util/ssl_.py)', 'urllib3.util (/home/ubuntu/miniconda3/envs/serve/lib/python3.10/site-packages/urllib3/util/__init__.py)'].
    monkey.patch_all()

-- Docs: https://docs.pytest.org/en/stable/how-to/capture-warnings.html
==================================================================================================== short test summary info ====================================================================================================
ERROR test/pytest/test_auto_recover.py::test_tp_inference - AttributeError: 'NoneType' object has no attribute 'fork_exec'
============================================================================================ 1 passed, 1 warning, 1 error in 12.15s =============================================================================================

Installation instructions

dev

Model Packaging

none

config.properties

none

Versions

 0.11

Repro instructions

pytest test/pytest/test_benchmark.py test/pytest/test_auto_recover.py

Possible Solution

gevent/gevent#1016 or not importing locust in test