opentelemetry-instrumentation: teach opentelemetry-instrument about gevent

Introduce
OTEL_PYTHON_AUTO_INSTRUMENTATION_EXPERIMENTAL_GEVENT_PATCH=patch_all
environment variable that calls gevent monkey module patch_all method
before starting up the distro and sdk. The environment variable should
useful also for apps instrumented via the opentelemetry-operator.

The flag removes the following warning (and hang) when running locust:
$ opentelemetry-instrument locust
/lib/python3.10/site-packages/locust/__init__.py:16: 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 gevent/gevent#1016. Modules that had direct imports (NOT patched): ['urllib3.util (/lib/python3.10/site-packages/urllib3/util/__init__.py)', 'urllib3.util.ssl_ (/lib/python3.10/site-packages/urllib3/util/ssl_.py)'].
  monkey.patch_all()

Author: xrmx

opentelemetry-instrumentation/README.rst

@@ -104,7 +104,13 @@ check `here <https://opentelemetry-python.readthedocs.io/en/stable/index.html#in
 * ``OTEL_PYTHON_DISABLED_INSTRUMENTATIONS``
 
 If set by the user, opentelemetry-instrument will read this environment variable to disable specific instrumentations.
-e.g OTEL_PYTHON_DISABLED_INSTRUMENTATIONS = "requests,django"
+e.g OTEL_PYTHON_DISABLED_INSTRUMENTATIONS="requests,django"
+
+* ``OTEL_PYTHON_AUTO_INSTRUMENTATION_EXPERIMENTAL_GEVENT_PATCH``
+
+If set by the user to `patch_all` , opentelemetry instrument will call the gevent monkeypatching method ``patch_all``.
+This is considered experimental but can be useful to instrument gevent applications.
+e.g OTEL_PYTHON_AUTO_INSTRUMENTATION_EXPERIMENTAL_GEVENT_PATCH=patch_all
 
 
 Examples

opentelemetry-instrumentation/src/opentelemetry/instrumentation/auto_instrumentation/__init__.py

@@ -12,6 +12,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from __future__ import annotations
+
 from argparse import REMAINDER, ArgumentParser
 from logging import getLogger
 from os import environ, execl, getcwd
@@ -130,6 +132,29 @@ def initialize(*, swallow_exceptions: bool = True) -> None:
             environ["PYTHONPATH"], dirname(abspath(__file__)), pathsep
         )
 
+    # handle optional gevent monkey patching. This is done via environment variables so it may be used from the
+    # opentelemetry operator
+    gevent_patch_env_variable_name = (
+        "OTEL_PYTHON_AUTO_INSTRUMENTATION_EXPERIMENTAL_GEVENT_PATCH"
+    )
+    gevent_patch: str | None = environ.get(gevent_patch_env_variable_name)
+    if gevent_patch is not None:
+        if gevent_patch != "patch_all":
+            _logger.error(
+                "%s values must be `patch_all`", gevent_patch_env_variable_name
+            )
+        else:
+            try:
+                from gevent import monkey
+
+                getattr(monkey, gevent_patch)()
+            except ImportError:
+                _logger.error(
+                    "Requested to monkey patch with gevent but gevent is not available"
+                )
+                if not swallow_exceptions:
+                    raise
+
     try:
         distro = _load_distro()
         distro.configure()

opentelemetry-instrumentation/test-requirements.txt

@@ -1,5 +1,6 @@
 asgiref==3.8.1
 Deprecated==1.2.14
+gevent==25.5.1
 iniconfig==2.0.0
 packaging==24.0
 pluggy==1.5.0

opentelemetry-instrumentation/tests/auto_instrumentation/test_initialize.py

@@ -72,3 +72,30 @@ def test_reraises_exceptions(self, load_distro_mock, logger_mock):
             )
 
         self.assertEqual("inner exception", str(em.exception))
+
+    @patch.dict(
+        "os.environ",
+        {
+            "OTEL_PYTHON_AUTO_INSTRUMENTATION_EXPERIMENTAL_GEVENT_PATCH": "patch_foo"
+        },
+    )
+    @patch("opentelemetry.instrumentation.auto_instrumentation._logger")
+    def test_handles_invalid_gevent_monkeypatch(self, logger_mock):
+        # pylint:disable=no-self-use
+        auto_instrumentation.initialize()
+        logger_mock.error.assert_called_once_with(
+            "%s values must be `patch_all`",
+            "OTEL_PYTHON_AUTO_INSTRUMENTATION_EXPERIMENTAL_GEVENT_PATCH",
+        )
+
+    @patch.dict(
+        "os.environ",
+        {
+            "OTEL_PYTHON_AUTO_INSTRUMENTATION_EXPERIMENTAL_GEVENT_PATCH": "patch_all"
+        },
+    )
+    @patch("opentelemetry.instrumentation.auto_instrumentation._logger")
+    def test_handles_patch_all_gevent_monkeypatch(self, logger_mock):
+        # pylint:disable=no-self-use
+        auto_instrumentation.initialize()
+        logger_mock.error.assert_not_called()